Abstract:
A charging and discharging control device includes a pantograph point voltage detection unit configured to detect a pantograph point voltage of a vehicle, a charging and discharging control unit configured to charge a power storage device provided in a vehicle when the pantograph point voltage is greater than or equal to a charging voltage threshold value and discharge the power storage device when the pantograph point voltage is less than a discharging voltage threshold value, a load determination unit configured to determine whether an absolute value of load power for the vehicle is less than a load power threshold value, and a charging and discharging control change unit configured to reduce any one or more of the charging voltage threshold value, the discharging voltage threshold value, and charging/discharging impedance when the absolute value of the load power is less than the load power threshold value.

Description:
RELATED APPLICATIONS 
     The present application is a National Phase of International Application Number PCT/JP2014/052891, filed Feb. 7, 2014. 
     TECHNICAL FIELD 
     The present invention relates to a mold heating device for a mold that vulcanizes a green tire, and a tire vulcanizer using the same. 
     BACKGROUND ART 
     Tire vulcanizers that vulcanize an unvulcanized green tire have been known. The tire vulcanizers heat a green tire from the outside by heating a mold having the green tire loaded therein using a heating medium. Moreover, the tire vulcanizers heat a green tire from the inside by supplying a heating medium consisting of steam with high temperature and high heat volume and a pressurizing medium consisting of non-condensable gas, such as nitrogen gas, to the internal space of the green tire. 
     As a configuration in which a mold is heated, for example, PTL 1 discloses a configuration in which an electromagnetic coil is arranged on an outer peripheral side of a mold and an outer surface of the mold is inductively heated. In this configuration, a side part heating unit including the electromagnetic coil is provided on an outer peripheral part of the mold. 
     Additionally, PTL 2 discloses a configuration in which a flexible planar heat generating element is provided on an outer peripheral side of a mold, and an outer surface of the mold is heated by the heat generating element. 
     CITATION LIST 
     Patent Literature 
     [PTL 1] Japanese Patent No. 5302804 
     [PTL 2] Japanese Unexamined Patent Application Publication No. 2011-126044 
     SUMMARY OF INVENTION 
     Technical Problem 
     Meanwhile, since tires to be valcanized have various sizes and are various types, the types of tire molds have increased. 
     For this reason, for example, in the configuration illustrated in PTL 1, the side part heating unit including the electromagnetic coil is provided on the outer peripheral part of the mold so as to be able to cope with the various molds. 
     However, in this configuration, the number of parts of the side heating unit including the electromagnetic coil increases, and substantial cost is required. 
     Additionally, in the configuration illustrated in PTL 2, induction-heating coils or the flexible planar heat generating elements should be attached to all owned tire molds, respectively. As a result, the number of induction-heating coils or flexible planar heat generating elements to be prepared has increased, and substantial cost is required. 
     An object of the invention is to provide a mold heating device and a tire vulcanizer that can achieve cost reduction. 
     Solution to Problem 
     According to a first aspect of the invention, there is provided a mold heating device for heating a mold that vulcanizes a tire. The mold heating device includes an electrothermal heater that has a heating wire disposed therein, has flexibility, and is wound around a peripheral surface of the mold; and a coupling part that couples end parts of the electrothermal heater together in a circumferential direction so that the circumferential length of the electrothermal heater can be changed. 
     According to a second aspect of the invention, in the mold heating device of the first aspect, the electrothermal heater may be configured to include a plurality of split belts that have a heating wire disposed therein and have flexibility, and end parts of the split belts may serve as the coupling parts. 
     According to a third aspect of the invention, in the mold heating device of the second aspect, the coupling part may be capable of changing the spacing between the split belts to be coupled together. 
     According to a fourth aspect of the invention, in the mold heating device of the third aspect, the coupling part may be constituted of an extendable member capable of being extended and compressed in the circumferential direction. 
     According to a fifth aspect of the invention, in the mold heating device of the third aspect, the coupling part may be constituted of a screw member that extends in the circumferential direction. 
     According to a sixth aspect of the invention, in the mold heating device of any one of the second aspect to the fifth aspect, the electrothermal heater may include a plurality of stages of the split belts in a height direction of the mold. 
     According to a seventh aspect of the invention, in the mold heating device of the sixth aspect, the electrothermal heater may be adapted such that arrangements, in the circumferential direction, of the split belts that are adjacent to each other in the height direction different from each other. 
     According to an eighth aspect of the invention, in the mold heating device of any one of the first aspect to the seventh aspect, the electrothermal heater may be capable of changing a range in which an electric current is made to flow in the circumferential direction. 
     According to a ninth aspect of the invention, in the mold heating device of any one of the first aspect to the eighth aspect, the density distribution of the heating wire in the electrothermal heater may be changed such that the amount of heat generation on an end part side in the circumferential direction becomes larger than the amount of heat generation on a middle side in the circumferential direction. 
     According to a tenth aspect of the invention, in the mold heating device of any one of the first aspect to the ninth aspect, a heat insulating material may be provided on an outer peripheral side of the electrothermal heater. 
     According to an eleventh aspect of the invention, in the mold heating device of any one of the first aspect to the tenth aspect, a fixing part that fixes the electrothermal heater to a peripheral surface of the mold may be included. 
     According to a twelfth aspect of the invention, in the mold heating device of the eleventh aspect, the fixing part may fix the electrothermal heater to the peripheral surface of the mold so as to cover the electrothermal heater. 
     According to a thirteenth aspect of the invention, there is a tire vulcanizer including a mold that vulcanizes a tire; and the mold heating device of any one of the first aspect to the twelfth aspect. 
     Advantageous Effects of Invention 
     According to the above-described mold heating device and tire vulcanizer, even in a case where the external diameter dimension of the mold varies, the electrothermal heater can be shared and used, and cost reduction can be achieved. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an elevational sectional view illustrating the configuration of a mold heating device and a tire vulcanizer in a first embodiment of the invention. 
         FIG. 2  is a cross-sectional view, taken along line A-A of  FIG. 1 , of the mold heating device and the tire vulcanizer in the first embodiment of the invention. 
         FIG. 3  is a view illustrating the configuration of the mold heating device in the first embodiment of the invention, and is a view when part of the mold heating device is seen from an outer peripheral side of the mold. 
         FIG. 4A  is a view illustrating the configuration of a coupling part between split belts in a first modification example of the first embodiment of the invention. 
         FIG. 4B  is a view illustrating the configuration of a coupling part between the split belts in another aspect of the first modification example of the first embodiment of the invention. 
         FIG. 5  is a view illustrating the configuration of a coupling part between the split belts in a second modification example of the first embodiment of the invention. 
         FIG. 6  is a view illustrating the configuration of a coupling part between the split belts in a third modification example of the first embodiment of the invention. 
         FIG. 7  is a view illustrating the configuration of a coupling part between the split belts in a fourth modification example of the first embodiment of the invention. 
         FIG. 8  is a view illustrating split belts in a fifth modification example of the first embodiment of the invention. 
         FIG. 9  is a view illustrating split belts in a sixth modification example of the first embodiment of the invention. 
         FIG. 10  is a view illustrating split belts in an eighth modification example of the first embodiment of the invention. 
         FIG. 11  is a view illustrating split belts in a ninth modification example of the first embodiment of the invention. 
         FIG. 12  is a view illustrating fixing parts of the split belts in a tenth modification example of the first embodiment of the invention. 
         FIG. 13  is a view illustrating the configuration of a mold heating device in a second embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     First Embodiment 
       FIG. 1  is a sectional view of a container section of a tire vulcanizer in a first embodiment of the invention.  FIG. 2  is a plan cross-sectional view of the container section of the tire vulcanizer in the first embodiment of the invention. 
     The tire vulcanizer  10  vulcanizes and molds an unvulcanized tire T. The tire vulcanizer  10  in this embodiment vulcanizes the tire T in a posture in which an axis thereof faces an upward-downward direction. 
     As illustrated in  FIGS. 1 and 2 , the tire vulcanizer  10  includes a mold  20 , a container  30  that encapsulates the mold  20 , and a mold heating device  100 . 
     The mold  20  includes a tread mold part  21  and a sidewall mold part  22 . 
     The tread mold part  21  forms a tread part and a shoulder part of the tire T. The tread mold part  21  is split into a plurality of pieces in a circumferential direction of the tire T. 
     The sidewall mold part  22  forms a sidewall part of the tire T. The sidewall mold parts  22  are respectively provided at the positions of both end edges of the tread mold part  21  in an upward-downward direction. 
     The container  30  is provided on a lower heating plate  11  of the tire vulcanizer  10 . The lower heating plate  11  forms an annular plate shape. The container  30  includes a bottom plate  32 , an upper disk  34 , a segment  36 , and an outer ring  37 . 
     The bottom plate  32  is fixed to the lower heating plate  11 . The bottom plate  32  is formed in an annular plate shape. The bottom plate  32  integrally has a lower sidewall mold part  22  on an upper surface thereof. 
     The center mechanism including a bladder  25  (rubber bag) into which a pressurizing heating medium for vulcanizing a green tire is introduced is installed in respective central openings  38  of the annular plate-shaped lower heating plate  11  and the bottom plate  32 . 
     The upper disk  34  is formed in an annular plate shape. The upper sidewall mold part  22  is integrally provided on a lower surface of the upper disk  34 . 
     The upper disk  34  is integrally provided on a lower surface of an upper heating plate  12  of the tire vulcanizer  10 . The upper heating plate  12  is driven so as to be lifted and lowered in the upward-downward direction by a lifting device (not illustrated). The upper heating plate  12  is also formed in an annular shape. Accordingly, the upper sidewall mold part  22  provided integrally with the upper disk  34  is lifted and lowered by the lifting device (not illustrated). 
     A plurality of the segments  36  are provided at intervals in the circumferential direction on an outer peripheral side of the tread mold part  21 . Each segment  36  is integrally fixed to an outer peripheral surface of each tread mold part  21  with a bolt (not illustrated). 
     The plurality of segments  36  are respectively provided on a guide plate  39  fixed on the bottom plate  32  so as to be movable in a radial direction. 
     An outer peripheral surface  36   s  of each segment  36  is formed so as to gradually spread downward to the outer peripheral side from above. The outer peripheral surface  36   s  of each segment  36  includes a groove  36   m  that is continuous in the upward-downward direction and has a T-shaped section. 
     The outer ring  37  is formed in an annular shape. The outer ring  37  is provided on outer peripheral sides of the plurality of segments  36  provided in the circumferential direction. The outer ring  37  is fixed to the lower surface of the upper disk  34 . Accordingly, the outer ring  37  is lifted and lowered integrally with the upper heating plate  12  by a lifting mechanism (not illustrated). 
     The outer ring  37  has, on an inner peripheral surface thereof, an inner-peripheral-side inclined surface  37   s  that gradually spreads downward to the outer peripheral side from above. A T-type guide  37   g  is formed at a position corresponding to each segment  36  on the inner-peripheral-side inclined surface  37   s . The T-type guide  37   g  is inserted into the groove  36   m  of each segment  36 . 
     If the outer ring  37  is lowered, the inner-peripheral-side inclined surface  37   s  and the outer peripheral surfaces  36   s  of the respective segments  36  are slidable on each other. Then, the outer peripheral surfaces  36   s  of the respective segments  36  are pressed to a radial inner peripheral side by the inner-peripheral-side inclined surface  37   s . Accordingly, the respective segments  36  move to the radial inner peripheral side. Additionally, if the outer ring  37  is lifted, the T-type guides  37   g  move upward while meshing with the grooves  36   m  of the segments  36 . Then, the respective segments  36  are pulled to a radial outer peripheral side by the T-type guides  37   g . Accordingly, the respective segments  36  move to the radial outer peripheral side. 
     That is, the tread mold parts  21  supported by the respective segments  36  are reciprocated in the radial direction by lifting and lowering the outer ring  37  using the lifting mechanism (not illustrated). In other words, the plurality of tread mold parts  21  that are arranged in the circumferential direction are expanded and compressed in the radial direction by lifting and lowering the outer ring  37  using the lifting mechanism (not illustrated). 
       FIG. 3  is a view illustrating the configuration of the mold heating device, and is a view when part of the mold heating device is seen from an outer peripheral side of the mold. 
     As illustrated in  FIG. 3 , the mold heating device  100  includes an electrothermal heater  101  wound around a peripheral surface of the mold  20 . The electrothermal heater  101  includes a plurality of split belts  110  and a coupling part  120 . 
     Each split belt  110  is formed in a belt shape with a predetermined width. The split belt  110  is made of materials within which a heating wire  111  is disposed and that have flexibility, for example, rubber-based materials, glass fabrics, or the like. 
     As such a split belt  110 , for example, rubber heaters, ceramic heaters, element heaters, glass fabric heaters, or the like can be used. Such a split belt  110  is provided for the peripheral surface of the mold  20 , and specifically, is provided along the outer peripheral surface of the outer ring  37  of the container  30 . The plurality of split belts  110  are arranged over the whole circumference of the mold  20 . That is, at least two split belts  110  may be provided. In this state, a spacing S is formed between the split belts  110  and  110  that are adjacent to each other in the circumferential direction. 
     Here, for example, the same number of split belts  110  as the number of the segments  36  may be provided, and the split belts  110  may be provided at positions that face the respective segments  36 . Additionally, a greater number of split belts  110  than the number of the segments  36  or a smaller number of split belts  110  than the number of the segments  36  may be provided. 
     The external diameter of the mold  20  varies according to the size of the tire T to be vulcanized. Therefore, the dimension of the spacing S between the split belts  110  and  110  varies according to the circumferential length of the outer peripheral surface of the outer ring  37  of the mold  20 . Accordingly, the electrothermal heater  101  can be fixed to the peripheral surface of the mold  20  by changing the circumferential length of the electrothermal heater  101 . 
     The coupling parts  120  are provided at the both end parts of the split belt  110 . The coupling part  120  couples together the split belts  110  and  110  that are adjacent to each other in the circumferential direction. Additionally, the coupling part  120  is able to change the spacing S between the split belts  110  and  110  to be coupled. As such a coupling part  120 , extendable members capable of being extended and compressed in the circumferential direction are used. This embodiment includes spring members  122  as the coupling part  120 . The spring members  122  are locked to latching parts  121  that are respectively formed at end parts of the split belts  110  and  110  that are adjacent to each other. The latching part  121  is formed so as to be perpendicular to the surface of the split belt  110 . 
     The circumferential length of the electrothermal heater  101  including the plurality of split belts  110  can be changed by the coupling part  120  consisting of such spring members  122 . 
     As illustrated in  FIGS. 1 and 2 , the mold heating device  100  has a heat insulating material  130  on an outer peripheral side of the electrothermal heater  101 . The heat insulating material  130  is formed in a cylindrical shape. 
     The heat insulating material  130  has metallic tubular bodies  131  and  132  on an inner peripheral part and an outer peripheral part thereof. The heat insulating material  130  between the tubular bodies  131  and  132  is filled with a heat insulating material  133  consisting of glass wool or the like. 
     Here, the heat insulating material  130  may be provided so as to directly come into contact with an outer peripheral surface of the electrothermal heater  101 . In this case, the heat insulating material  130  can be made to function as a fixing member that fixes the electrothermal heater  101 . 
     Additionally, the heat insulating material  130  may be provided with a gap from the outer peripheral surface of the electrothermal heater  101  on an outer peripheral side of the outer peripheral surface of the electrothermal heater  101 . 
     According to the mold heating device  100  and the tire vulcanizer  10  of the above-described embodiment, end parts of the electrothermal heater  101  are coupled together in the circumferential direction by the coupling part  120  so that the circumferential length of the electrothermal heater  101  with flexibility can be changed. Accordingly, even in a case where the external diameter dimension of the mold  20  varies according to the size of the tire T to be vulcanized, the electrothermal heater  101  can be shared and used. Accordingly, even in a case where a number of molds  20  are present, the number of electrothermal heaters  101  can be suppressed, and cost reduction can be achieved. 
     Moreover, since the mold  20  is directly heated by the electrothermal heater  101 , there is no heat dissipation caused by a supply pipe and a recovery pipe for a heating medium unlike cases where heating media, such as steam, are used. Therefore, heating efficiency can improve and energy saving can be achieved. 
     Additionally, the electrothermal heater  101  is constituted of the plurality of split belts  110 , and end parts of the plurality of split belts  110  serve as the coupling parts  120 . 
     Accordingly, the electrothermal heater  101  can be easily attached to and detached from the peripheral surface of the mold  20 . 
     Moreover, the coupling part  120  can change the spacing S between the split belts  110  to be coupled. Accordingly, the circumferential length of the electrothermal heater  101  can be easily adjusted according to the external diameter dimension of the mold  20 . 
     Additionally, the coupling part  120  is constituted of the spring members  122  capable of being extended and compressed in the circumferential direction. Accordingly, as the spring members  122  are extended and compressed, the circumferential length of the electrothermal heater  101  can be easily adjusted. Additionally, the respective split belts  110  can be brought into close contact with the peripheral surface of the mold  20  by the pulling forces of the spring members  122 . Therefore, heating using the split belts  110  can be efficiently performed. 
     In addition, the heat insulating material  130  is provided on the outer peripheral side of the electrothermal heater  101 . Accordingly, heating using the electrothermal heater  101  can be more efficiently performed. 
     Meanwhile, if the electrothermal heater  101  is too close to the tire T, unevenness easily occurs in the temperature distribution in the surface of the tire T. In contrast, in this embodiment, the electrothermal heater  101  is provided on the outer peripheral side of the outer ring  37 . For this reason, the tread mold parts  21 , the segments  36 , and the outer ring  37  are interposed between the tread parts of the tire T. Therefore, heat using the electrothermal heater  101  is uniformly radiated, and the tire T can be vulcanized with excellent quality. 
     MODIFICATION EXAMPLE OF FIRST EMBODIMENT 
     In the first embodiment, the spring members  122  are provided as the coupling part  120 . However, the invention is not limited to this. 
     First Modification Example 
       FIGS. 4A and 4B  are views illustrating the configuration of a coupling part between the split belts in the first modification example of the first embodiment of the invention. 
     As illustrated in  FIG. 4A , bolts (screw members)  123  and nuts (screw members)  124  that extend in the circumferential direction can also be used as the coupling part  120 . 
     The spacing S between the split belts  110  and  110  can be changed by changing the screwing positions of the nuts  124  to the bolts  123 . 
     Additionally, as illustrated in  FIG. 4B , it is not necessary to directly couple the end parts of the split belts  110  and  110  together with the bolts  123  and the nuts  124 . Split belts  119  may be wound the outer peripheral sides of the split belts  110 , and both ends thereof may be coupled together by the bolts  123  and the nuts  124 . In this case, seat surface parts  115  orthogonal to the surfaces of the split belt  119  are formed at end parts of the split belt  119 . The seat surface parts  115  of the split belts  119  are fastened to each other with the bolts  123  and the nuts  124  in a state where the seat surface parts  115  and  115  are separated from each other. 
     Second Modification Example 
       FIG. 5  is a view illustrating the configuration of a coupling part between the split belts in a second modification example of the first embodiment of the invention. 
     As illustrated in  FIG. 5 , a hook-and-loop fastener  125  may be used as the coupling part  120 . In this case, the end parts of the first split belt  110  and the second split belt  110  overlap each other and are coupled together by the hook-and-loop fastener  125 . 
     The end parts of the first split belt  110  and the second split belt  110  may not be directly coupled together by the hook-and-loop fastener  125 , but a belt or the like may be wound around the outer peripheral sides of the split belts  110  and both end parts of the belt may be coupled together by the hook-and-loop fastener  125 . 
     Third Modification Example 
       FIG. 6  is a view illustrating the configuration of a coupling part between the split belts in a third modification example of the first embodiment of the invention. 
     As illustrated in  FIG. 6 , a belt  126  that couples the split belts  110  together and a buckle  127  that adjusts the length of the belt  126  may be provided as the coupling part  120 . 
     The belt  126  may be wound around the plurality of split belts  110 , and the end parts of the first split belt  110  and the second split belt  110  may be respectively attached to the belt. 
     Fourth Modification Example 
       FIG. 7  is a view illustrating the configuration of a coupling part between the split belts in a fourth modification example of the first embodiment of the invention. 
     As illustrated in  FIG. 7 , as the coupling part  120 , a hook  129   f  may be provided at a first end part  128   a  of a belt  128  that couples the split belts  110  together, and a locking hole  129   h  to which the hook  129   f  is locked may be provided at a second end part  128   b . The belt  128  may be wound around the plurality of split belts  110 , and the end parts of the first split belt  110  and the second split belt  110  may be respectively attached to the belt. 
     Although the electrothermal heater  101  is provided in the first embodiment, the configuration thereof may be provided as illustrated below, in a plurality of modification examples. 
     Fifth Modification Example 
       FIG. 8  is a view illustrating the configuration of split belts in a fifth modification example of the first embodiment of the invention. 
     The width dimension, in the up-down direction, of the split belts  110  that constitute the electrothermal heater  101  is not necessarily equal to the height of the outer ring  37  of the mold  20 . For example, as illustrated in  FIG. 8 , the split belts  110  having a width dimension smaller than the height of the outer ring  37  may be provided. 
     Moreover, in the electrothermal heater  101 , the narrow split belts  110  may be arranged in a plurality of stages in a height direction of the mold  20 . The number of installed stages of the split belts  110  in the upward-downward direction (height direction) can be changed according to the mold  20  with various heights, and the electrothermal heater  101  can be installed in an optimal arrangement. 
     Sixth Modification Example 
       FIG. 9  is a view illustrating the configuration of split belts in a sixth modification example of the first embodiment of the invention. 
     As illustrated in  FIG. 9 , the split belts  110  that constitute the electrothermal heater  101  are installed in a plurality of stages in the upward-downward direction (height direction). Additionally, the split belts  110  that are adjacent to each other in the upward-downward direction (height direction) may have an alternate arrangement in which the arrangements thereof in the circumferential direction are different from each other. 
     Accordingly, the distribution of heating performance in the circumferential direction can be made uniform. 
     In the first embodiment, the electrothermal heater  101  includes the heating wires  111 . However, this configuration may be an arbitrary configuration. 
     Seventh Modification Example 
     For example, each split belt  110  may have a plurality of sets of the heating wires  111  having different electric capacities. Accordingly, when heating properties are different in a preheating step of the container  30  and a vulcanizing step of the tire T, energization can be performed to perform heating after switching is made between the heating wires  111  having different electric capacities. 
     Eighth Modification Example 
       FIG. 10  is a view illustrating the configuration of split belts in an eighth modification example of the first embodiment of the invention. 
     The heating performance of the mold heating device  100  is inferior in a joining part between the split belts  110  and  110  as compared to the parts covered with the split belts  110 . Thus, the electrothermal heater  101  may be adapted to be able to change the range in which an electric current is made to flow to the heating wire  111  in the circumferential direction. For example, in the electrothermal heater  101 , the density distribution of the heating wire  111  may be changed such that the amount of heat generation becomes larger on an end part side in the circumferential direction than on a middle side in the circumferential direction. 
     As illustrated in  FIG. 10 , the density of the heating wire  111  is increased in an end part  110   s  of the split belt  110 . Accordingly, heating performance becomes high in the vicinity of the end part  110   s  of the split belt  110 , and the heating performance at the joining part of the split belts  110  and  110  can be compensated for. 
     Ninth Modification Example 
       FIG. 11  is a view illustrating the configuration of split belts in a ninth modification example of the first embodiment of the invention. 
     As illustrated in  FIG. 11 , a plurality of sets of heating wires  111  may be provided in the circumferential direction in the split belt  110 . In this case, the respective heating wires  111  are adapted to be able to individually control ON/OFF for energization and an increase or decrease in the amount of energization. Accordingly, the electrothermal heater  101  is able to change a range in which an electric current is made to flow to the heating wires  111  in the circumferential direction. Moreover, the electrothermal heater  101  is able to perform heating with suitable temperature distribution in accordance with the mold  20  on which the electrothermal heater  101  is mounted. Moreover, when the circumferential length of the mold  20  becomes short, energization to unnecessary parts of the electrothermal heater  101  may be suppressed. 
     Additionally, in the configurations illustrated in  FIGS. 3 and 4A , the spring members  122 , the bolts  123 , and the nuts  124  may be electrically connected to the heating wires  111 . By energizing the heating wire  111 , the spring members  122 , the bolts  123 , and the nuts  124  can be made to generate heat to compensate for the heating performance in the joining part between the split belts  110  and  110 . 
     Moreover, in the first embodiment, the circumferential length of the electrothermal heater  101  is changed by adjusting the circumferential length of the coupling part  120 . However, the invention is not limited to this. For example, the circumferential length may be changed by changing the number of couplings between the split belts  110  that constitute the electrothermal heater  101 . 
     In the first embodiment, the electrothermal heater  101  is configured by coupling the plurality of split belts  110 . However, the invention is not limited to this. One split belt  110  that is elongated in a belt shape may be wound around the peripheral surface of the mold  20 , and this split belt may be used as the electrothermal heater  101 . In this case, the circumferential length of the electrothermal heater  101  is changed by changing the spacing S between end parts of the one split belt  110  using the coupling part  120 . 
     Tenth Modification Example 
       FIG. 12  is a view illustrating fixing parts of the split belts in a tenth modification example of the first embodiment of the invention. 
     For example, as illustrated in  FIG. 12 , the electrothermal heater  101  may be fixed to the peripheral surface of the mold  20  by fixing parts  112 A so as to cover the electrothermal heater  101 . In this case, the fixing parts  112 A are fixed to the mold  20  with fixing bolts  112   b.    
     Additionally, the electrothermal heater  101  itself may be directly fixed to the peripheral surface of the mold  20  with the fixing bolts  112   b  without using the fixing parts  112 A. 
     Second Embodiment 
     Next, a second embodiment of the mold heating device and the tire vulcanizer related to the invention will be described. The mold heating device illustrated in the second embodiment is different from the mold heating device of the first embodiment only in terms of including actuators for providing the split belts  110  along the peripheral surface of the mold  20 . Therefore, in the description of the second embodiment, description will be made with the same reference numerals given to the same parts as those of the first embodiment, and duplicate descriptions will be omitted. That is, the description of the overall configuration of the tire vulcanizer  10  or the mold heating device  100  that is the same as the configuration described in the first embodiment will be omitted. 
       FIG. 13  is a view illustrating the configuration of the mold heating device in the second embodiment. 
     As illustrated in  FIG. 13 , each of the split belts  110  that constitute the electrothermal heater  101  includes actuators  200  for arranging the split belt on the peripheral surface of the mold  20 . 
     The actuators  200  consist of air cylinders, hydraulic cylinders, or the like. Tip parts of the actuator  200  are coupled to each split belt  110 . 
     The split belt  110  supported by such actuators  200  and  200  is arranged at positions apart from the peripheral surface of the mold  20  towards the outer peripheral side. 
     When the split belt  110  is arranged along the peripheral surface of the mold  20 , the actuators  200  and  200  are extended. Then, the split belt  110  with flexibility is deformed so as to run along the peripheral surface of the mold  20 . Accordingly, the inner periphery of the split belt  110  becomes a circular-arc with the same curvature as that of the peripheral surface of the mold  20 . The electrothermal heater  101  heats the mold  20  in this state. Accordingly, replacement or mounting work of the split belt  110  can be easily and reliably performed. For example, in the electrothermal heater  101 , each split belt  110  may be fixed to the peripheral surface of the mold  20  by a worker after the split belt  110  is pressed against the mold  20  by the actuators  200  and  200 . 
     Other Embodiments 
     In addition, the invention is not limited to the above-described respective embodiments, and design changes can be made without departing from the concept of the invention. 
     For example, the heating of the mold  20  may be used in combination with a technique using heating media, such as steam. 
     Additionally, the heating from the upper and lower surfaces of the mold  20  may be performed using an electrothermal heater or may be performed using heating media, such as steam. 
     Moreover, according to the configuration of the above respective embodiments, it is possible to heat the mold  20  from the outer peripheral side surface, using the electrothermal heater  101 . However, the invention is not limited to the configurations of the mold  20  as illustrated in the above respective embodiments. For example, the above configuration can also be applied to a case where a mold split into two upper and lower parts is used. 
     INDUSTRIAL APPLICABILITY 
     By changing the circumferential length of the electrothermal heater with flexibility to fix the electrothermal heater to the peripheral surface of a mold, even in a case where the external diameter dimensions of the mold varies, the electrothermal heater can be shared and used, and cost reduction can be achieved. 
     REFERENCE SIGNS LIST 
     
         
         
           
               10 : TIRE VULCANIZER 
               11 : LOWER HEATING PLATE 
               12 : UPPER HEATING PLATE 
               20 : MOLD 
               21 : TREAD MOLD PART 
               22 : SIDEWALL MOLD PART 
               25 : BLADDER 
               30 : CONTAINER 
               32 : BOTTOM PLATE 
               33 : LOWER DISK 
               34 : UPPER DISK 
               36 : SEGMENT 
               36   m : GROOVE 
               36   s : OUTER PERIPHERAL SURFACE 
               37 : OUTER RING 
               37   g : T-TYPE GUIDE 
               37   s : INNER-PERIPHERAL-SIDE INCLINED SURFACE 
               38 : OPENING 
               39 : GUIDE PLATE 
               100 : MOLD HEATING DEVICE 
               101 : ELECTROTHERMAL HEATER 
               110 : SPLIT BELT 
               110   s : END PART 
               111 : HEATING WIRE 
               112 A: FIXING PART 
               112 B: FIXING BOLT 
               115 : SEAT SURFACE PART 
               119 : BELT 
               120 : COUPLING PART 
               121 : LATCHING PART 
               122 : SPRING MEMBER 
               123 : BOLT (SCREW MEMBER) 
               124 : NUT (SCREW MEMBER) 
               125 : HOOK-AND-LOOP FASTENER 
               126 : BELT 
               127 : BUCKLE 
               128 : BELT 
               128   a : END PART 
               128   b : END PART 
               129   f : HOOK 
               129 H: LOCKING HOLE 
               130 : HEAT INSULATING MATERIAL 
               131 : TUBULAR BODY 
               133 : HEAT INSULATING MATERIAL 
               200 : ACTUATOR 
             S: SPACING 
             T: TIRE