JP2005148049A - Method and device for detecting foreign matter in tire, tire inspection device, tire molding machine, and tire uniformity machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device for detecting foreign matter in a tire capable of easily finding a magnetic metal piece buried in the vicinity of the surface layer of the tire as the foreign matter, a tire inspection device, and a tire molding machine and a tire uniformity machine provided with the inspection device. <P>SOLUTION: This device for detecting the foreign matter in a tire comprises a sensor unit 1 including a magnetic sensor 10 composed of magnetic resistance elements 11 and 12, the electric resistances of which are changed in conformation to the quantity of cross flux, and a variable resistance element 13 provided so as to form a bridge circuit with the magnetic resistance elements 11 and 12. A main unit 5 comprises a differential amplifier 2, a determination circuit 3, and a power source 4. The voltage from the power source 4 is applied to two input temrinals of the bridge circuit, and the output of the bridge circuit is inputted to a non-inverting input terminal and an inverting input terminal of the differential amplifier 2. The determination circuit 3 determines the presence of the magnetic metal piece in the vicinity of the magnetic sensor 10, when the value of the voltage outputted from the differential amplifier 2 is larger than a predetermined reference value, and outputs the determination result. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for detecting foreign matter in a tire for detecting a magnetic material such as a metal piece as a foreign matter embedded in the vicinity of a surface layer of a tire, a tire inspection apparatus, a tire molding machine including the same, and a tire uniformity machine.

  Conventionally, various inspections are performed before shipping a tire as a product. For example, as disclosed in Japanese Patent Application Laid-Open No. 7-9585, it is inspected whether there is an abnormality in the splice portion of a belt-like member embedded in a tire, or Japanese Patent Application Laid-Open No. 62-195503 or Japanese Patent Application Laid-Open No. It is inspected whether the rubber thickness on the tire surface is uniform as disclosed in Japanese Patent No. -304009.

  Further, in an apparatus as disclosed in Japanese Patent Laid-Open Nos. 9-5246 and 2003-145640, the joining state of rubber is monitored during tire molding by a tire molding machine, and beads are automatically and reliably attached. The tire quality is improved by insertion.

In addition, with respect to the completed tire, a uniformity test for measuring the variation in force generated by a rotating tire using a uniformity tester as disclosed in JP-A-2002-350273, A dynamic balance test for measuring the eccentric state is performed.
Japanese Unexamined Patent Publication No. 7-9585 JP-A-62-195503 JP-A-8-304009 Japanese Patent Laid-Open No. 9-5246 Japanese Patent Laid-Open No. 2003-145640 JP 2002-350273 A

  However, when a minute magnetic metal piece as a foreign object is embedded near the surface of the tire, it is difficult for an inspector to find the foreign object before shipping the tire as a product, and the foreign object is embedded. It may be shipped as is.

  Even if the above-described minute magnetic metal piece is embedded in the tire, it does not lead to an accident, but it may cause discomfort to the user and the quality as a product will be reduced.

  SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a method for detecting foreign matter in a tire, a device thereof, a tire inspection device, and a tire inspection device capable of easily finding a magnetic metal piece as a foreign matter embedded in the vicinity of the surface of the tire. It is to provide a tire forming machine and a tire uniformity machine.

  In order to achieve the above object, the present invention provides a foreign object detection method for detecting a magnetic metal piece, which is a foreign object existing in the vicinity of a surface layer in a tire, from the outside of the tire, and is present within a predetermined distance. An electric circuit or a computer apparatus is used based on the electric signal output from the detection unit that moves while maintaining a certain distance from the surface of the tire, using a detection unit that outputs an electric signal in response to the magnetic metal piece. A foreign object detection method in a tire is proposed in which the presence of a magnetic metal piece that is a foreign object is detected by a determination means comprising:

  In the method for detecting foreign matter in a tire according to the present invention, an electric signal is output in response to a magnetic metal piece existing in the vicinity of a surface layer in the tire within a predetermined distance by a detection unit that moves at a constant distance from the surface of the tire. The presence of the magnetic metal piece that is a foreign object is detected based on the electrical signal output from the detection unit by the determination means.

  Furthermore, in order to achieve the above object, the present invention is a foreign object detection method for detecting a magnetic metal piece, which is a foreign object existing in the vicinity of a surface layer in a tire, from the outside of the tire. Using a detection unit that outputs an electrical signal that changes in accordance with the amount and a magnet disposed at a predetermined position in the vicinity of the detection unit, the magnetic flux in one magnetic pole of the magnet intersects the surface of the tire and the detection unit In the state, based on the electric signal output from the detection unit moving at a certain distance from the surface of the tire, the determination means comprising an electric circuit or a computer device determines the presence of the magnetic metal piece as the foreign object. A method for detecting foreign matter in a tire to be detected is proposed.

  In the method for detecting foreign matter in a tire according to the present invention, a magnetic metal piece as a foreign matter is detected in the vicinity of the surface layer in the tire by moving the magnet and the detection unit while maintaining a certain distance from the surface of the tire. Since the electric signal output from the unit changes in accordance with the amount of change in the cross magnetic flux due to the magnetic metal piece, the presence of the magnetic metal piece as the foreign object is detected.

  In order to achieve the above object, the present invention provides a foreign matter detection device for a tire in a tire that detects a magnetic metal piece, which is a foreign matter embedded in the vicinity of a surface layer in the tire, from the outside of the tire, and includes a sensor unit. And a main unit, wherein the sensor unit has a detection unit that outputs an electric signal in response to the magnetic metal piece existing within a predetermined distance, and the main unit is output from the detection unit There is proposed a foreign matter detection device in a tire having a determination means for determining whether or not the magnetic metal piece is present based on an electric signal and outputting the determination result.

  In the foreign matter detection device in a tire according to the present invention, the sensor unit of the sensor unit that moves while maintaining a certain distance from the surface of the tire of the sensor unit reacts with a magnetic metal piece existing in the vicinity of the surface layer in the tire within a predetermined distance. An electric signal is output, and the presence of the magnetic metal piece that is a foreign object is detected based on the electric signal output from the detector by the determination unit of the main unit.

  In the foreign object detection device according to the present invention, the detection unit may be configured such that one of the magnetic poles is located at a predetermined distance from the surface of the tire and the magnetic flux of the one magnetic pole intersects the surface of the tire when detecting the foreign object. And a magnetic sensor that is disposed in the vicinity of the magnet and that intersects with the magnetic flux in the one magnetic pole and outputs an electrical signal corresponding to the amount of the crossed magnetic flux A foreign matter detection device is proposed.

  In the foreign matter detection device in a tire according to the present invention, there is a magnetic metal piece that is a foreign matter in the vicinity of the surface layer in the tire by moving the magnet and the magnetic sensor of the sensor unit at a certain distance from the surface of the tire. Then, since the electrical signal output from the magnetic sensor changes in accordance with the amount of change in the cross magnetic flux due to the magnetic metal piece, the presence of the magnetic metal piece as the foreign object is detected by the main unit.

  Further, the present invention proposes a foreign matter detection device in a tire in which the magnet has a cylindrical shape and the magnetic sensor is arranged in the cylinder of the magnet so as to be surrounded by the magnet. To do.

  In the foreign matter detection device in a tire according to the present invention, a magnetic sensor is arranged in a cylinder of a magnet so as to be surrounded by a cylindrical magnet. Since the incident light is centered on the sensor, it is possible to detect a magnetic metal piece that exists at least at a position intersecting with the magnetic flux in the ring.

  In the foreign object detection device according to the present invention, the magnet may be a DC electromagnet, and the main unit may change a DC power source that supplies a DC current to the DC electromagnet and a DC current amount that is supplied to the DC magnet. A device for detecting a foreign matter in a tire having current varying means for causing a current to be caused is proposed.

  In the tire foreign matter detection device of the present invention, the reach of magnetic flux radiated from the DC electromagnet is changed by changing the amount of current supplied to the DC electromagnet by the current varying means. The detection depth of the magnetic metal piece can be changed.

  According to the present invention, in the foreign object detection device, the magnetic sensor is disposed so as to intersect with the magnetic flux in the one magnetic pole, and the first and second electric resistance values change according to the amount of the intersecting magnetic flux. The sensor unit includes at least one variable resistance element provided to form a bridge circuit together with the first and second magnetoresistance elements, and the main unit includes the bridge circuit A power supply circuit for applying a voltage to the two input terminals of the bridge circuit, and the determining means outputs the magnetic signal when a voltage value output from the two output terminals of the bridge circuit is greater than a predetermined reference value. A foreign object detection device in a tire having means for determining that a body metal piece is present and outputting a determination result is proposed.

  In the foreign matter detection device in a tire according to the present invention, the presence or absence of the magnetic metal piece is determined based on the output voltage of the bridge circuit including the first and second magnetoresistive elements. Variations can be detected.

  In the foreign object detection device according to the present invention, the sensor unit rotates in contact with the surface of the tire and moves the one magnetic pole or the detection unit while maintaining a certain distance from the surface of the tire. A foreign object detection device in a tire having possible wheels is proposed.

  In the foreign matter detection device in a tire according to the present invention, the one magnetic pole or the detection unit is movable in a state where a certain distance is maintained from the surface of the tire by a wheel.

  In the foreign object detection apparatus according to the present invention, the sensor unit includes two wheels having a rotation axis on the same straight line and being rotatable separately from each other and having a circumferential surface width equal to or greater than a predetermined value. A foreign object detection device in a tire is proposed.

  In the foreign matter detection device in a tire according to the present invention, the magnet or the detection unit is moved in a state of maintaining a certain distance from the surface of the tire by two parallel wheels.

  In the foreign object detection device according to the present invention, the sensor unit includes a foreign object detection device in a tire provided with two wheels whose rotation centers are located on the same straight line and whose rotation axes are parallel to each other. suggest.

  In the foreign matter detection device in a tire according to the present invention, the magnet or the detection unit is moved in a state of maintaining a certain distance from the surface of the tire by two wheels moving on the same straight line.

  Further, the present invention is a foreign matter detection device in a tire for detecting a magnetic metal piece that is a foreign matter embedded in the vicinity of the surface layer in the tire from the outside of the tire, comprising a sensor unit and a main unit, The sensor unit reacts with the magnetic metal piece existing within a predetermined distance and outputs an electric signal, and has a rotation axis on the same straight line and is rotatable separately from each other, and is attached to the surface of the tire. Two wheels having a circumferential surface width greater than or equal to a predetermined value that can move while abutting and rotating while maintaining a predetermined distance from the surface of the tire, and perpendicular to the rotational axis of the wheel and on the tire surface A swing mechanism having a parallel pivot shaft and pivotally supporting a wheel support portion supporting the two wheels about the pivot shaft, and the main unit detects the detection Electricity output from the unit It determines whether there is the magnetic metal pieces propose foreign object detection device in a tire having a judging means for outputting the determination result based on the item.

  In the tire foreign matter detection device according to the present invention, the wheel support portion can be rotated around the rotation axis by the swing mechanism portion. The portion can be rotated, and the two wheels can be always kept in contact with the tire surface. As a result, even if the curve or uneven state of the tire surface changes, the tire can move in a state in which the distance between the magnet or the detection unit and the tire surface is kept constant.

  Further, the present invention provides the foreign object detection device described above, wherein the foreign object in the tire is provided with a holding means for holding the wheel support portion at a predetermined position in the rotation direction about the rotation shaft in a rotatable state. A detection device is proposed.

  In the foreign matter detection device in a tire according to the present invention, the wheel support portion is held at a predetermined position in the rotation direction about the rotation shaft while the wheel support portion is rotatable by the holding means. When the wheel is turned and deviated from the predetermined position in the rotational direction and no external force is applied to the wheel support portion in the rotational direction, the holding means causes the wheel support portion to move to the predetermined position in the rotational direction. Returned to

  In the foreign object detection device according to the present invention, the sensor unit has a second rotation axis that is perpendicular to the rotation axis of the wheel and perpendicular to the tire surface, and supports the two wheels. A foreign object detection device in a tire is provided that includes a swing mechanism that rotatably supports a portion about the rotation axis as a central axis.

  In the tire foreign matter detecting device according to the present invention, the wheel support portion can be rotated about the second rotation axis by the swing mechanism portion, so that the wheel surface support portion can be turned according to the curve or uneven state of the tire surface. The wheel support portion can be rotated, and the two wheels can always be kept in contact with the tire surface. As a result, even if the curve or uneven state of the tire surface changes, the tire can move in a state in which the distance between the magnet or the detection unit and the tire surface is kept constant.

  In the foreign object detection apparatus according to the present invention, a second holding unit is provided that holds the wheel support portion at a predetermined position in a rotation direction around the second rotation shaft in a state where the wheel support portion is rotatable. A foreign object detection device in a tire is proposed.

  In the tire foreign matter detection device according to the present invention, the second holding means holds the wheel support portion at a predetermined position in the rotation direction around the second rotation axis in a state where the wheel support portion is rotatable. When the wheel support portion is rotated to be in a state of being deviated from the predetermined position in the rotation direction and the external force applied to the wheel support portion in the rotation direction is lost, the wheel support portion is moved by the second holding means. The rotation direction is returned to a predetermined position.

  Further, according to the present invention, in the foreign object detection device, the sensor unit includes a fixing portion that fixes the entire unit to another member, and the fixing portion is applied to the tire surface with a predetermined pressure against the tire surface. The present invention proposes a foreign matter detecting device in a tire provided with a return mechanism portion that presses the swing mechanism portion in a direction perpendicular to the surface of the tire so as to come into contact therewith.

  In the tire foreign matter detecting device according to the present invention, the swinging mechanism portion is pressed in the vertical direction against the tire surface so that the wheel comes into contact with the tire surface with a predetermined pressure by the pull-back mechanism portion. Therefore, the two wheels can always be kept in contact with the tire surface in accordance with the curved or uneven state of the tire surface. As a result, even if the curve or uneven state of the tire surface changes, the tire can move in a state in which the distance between the magnet or the detection unit and the tire surface is kept constant.

  In order to achieve the above object, the present invention is a tire inspection apparatus for detecting unnecessary magnetic metal pieces embedded in the vicinity of a surface layer in a tire to be inspected, wherein the tire to be inspected is Rotating means for rotating, and a foreign matter detecting device in a tire according to any one of claims 3 to 15, wherein the detection unit of the magnetic material detecting device is disposed at a predetermined distance from the surface in the inspection region of the tire. A tire inspection apparatus having means for holding in position is proposed.

  In the tire inspection apparatus of the present invention, since the foreign object is detected by the foreign object detection device while rotating the tire, the foreign object can be detected at high speed over the entire tire.

  In order to achieve the above object, the present invention proposes a tire molding machine provided with the tire inspection apparatus according to claim 16.

  In the tire molding machine of the present invention, foreign matter detection over the entire tire can be performed at high speed while molding the tire or subsequent to molding.

  In order to achieve the above object, the present invention proposes a tire uniformity machine provided with the tire inspection apparatus according to claim 16.

  In the tire uniformity machine of the present invention, it is possible to detect foreign matter over the entire tire at a high speed while measuring the tire uniformity or after the measurement.

  According to the foreign matter detection method in a tire of the present invention, it is possible to easily find a magnetic metal piece as a foreign matter embedded in the vicinity of the surface layer of a tire that is difficult to find by an inspector's visual observation. Since it is possible to avoid the shipping of the embedded tire as a product, the quality of the shipped product can be improved.

  Further, according to the foreign matter detecting device in a tire of the present invention, it is possible to easily find a magnetic metal piece as a foreign matter embedded in the vicinity of the surface layer of the tire which is difficult to find by visual inspection by an inspector. Since it is possible to avoid shipping as a tire product in which various foreign substances are embedded, the quality of the shipped product can be improved.

  Furthermore, according to the foreign matter detection device in a tire of the present invention, in addition to the above-described effect, the detection unit is configured by a magnet that supplies a magnetic bias and a magnetic sensor that outputs an electrical signal corresponding to the crossed magnetic flux. The presence of a minute magnetic metal piece can be easily detected.

  Furthermore, according to the foreign matter detection device in a tire of the present invention, in addition to the above effects, a magnetic sensor is arranged in the cylinder of the cylindrical magnet, so that a minute magnetic field change due to the magnetic metal piece in the tire can be detected. It can be easily detected.

  Furthermore, according to the foreign matter detection device in a tire of the present invention, in addition to the above-described effect, the magnet is constituted by a DC electromagnet, thereby detecting the tire surface from the tire surface by changing the energization amount to the DC electromagnet. The possible depth can be adjusted.

  Furthermore, according to the foreign matter detection device in a tire of the present invention, in addition to the above-described effect, the detection unit is configured by first and second magnetoresistive elements, and the first and second magnetoresistive elements and the variable resistance are configured. Since the bridge circuit is configured by the resistor, the noise mixed in the output of the first and second magnetoresistive elements and the noise mixed in the output of the variable resistor cancel each other, so that the influence of external noise can be reduced. More accurate detection can be performed.

  Furthermore, according to the foreign matter detection device in a tire of the present invention, in addition to the above-described effect, the distance between the tire surface, the magnet and the detection unit can be kept constant by the wheel. Detection malfunction due to position fluctuations can be suppressed.

  Further, according to the tire inspection apparatus of the present invention, it is possible to easily find a magnetic metal piece as a foreign object embedded in the vicinity of the surface layer of the tire that is difficult to be detected by the inspector's visual observation, and such a foreign object is embedded. Since it is possible to avoid the shipping of tires that are used as products, the quality of shipped products can be improved.

  Further, according to the tire molding machine and the tire uniformity machine of the present invention, the tire inspection can be performed following or simultaneously with the molding of the tire and the uniformity measurement, so that the inspection process can be simplified. .

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram illustrating a foreign matter detection device in a tire according to a first embodiment of the present invention. In the figure, 1 is a sensor unit, 2 is a differential amplifier, 3 is a determination circuit, 4 is a power supply, and the differential amplifier 2, determination circuit 3 and power supply 4 are provided in the main unit 5.

  The differential amplifier 2 receives an electrical signal output from the sensor unit 1 and outputs a voltage obtained by differentially amplifying the electrical signal to the determination circuit 3.

  The determination circuit 3 is composed of an electric circuit such as a comparator or a computer device, and detects a magnetic metal piece as a foreign object when the voltage output from the differential amplifier 2 falls within a predetermined detection range. We will inform you as having done.

  The power supply 4 inputs a commercial power supply 100V, supplies a voltage of + 5V to the sensor unit 1 and supplies a voltage of + 12V and −12V to the differential amplifier 2.

  The sensor unit 1 includes a magnetic sensor 10 in which two semiconductor magnetoresistive elements (hereinafter referred to as magnetoresistive elements) 11 and 12 are connected in series, and a three-terminal variable resistive element 13, and a bridge circuit is formed by these. . Here, the magnetoresistive element is an element whose electric resistance value changes depending on the amount of magnetic flux intersecting the element.

  In the bridge circuit configuration, one end of the variable resistance element 13 is connected to one end of the magnetoresistive element 11 and a voltage of +5 V supplied from the power source 4 is applied. The other end of the magnetoresistive element 11 is connected to one end of the magnetoresistive element 12 and the non-inverting input terminal (+) of the differential amplifier 2. The other end of the magnetoresistive element 12 is connected to the other end of the variable resistance element 13 and to the ground terminal (GND) of the power supply 4. Furthermore, the variable terminal of the variable resistance element 13 is connected to the inverting input terminal (−) of the differential amplifier 2.

  The sensor unit 1 has a configuration shown in FIGS. 2 is a side view of the sensor unit 1, FIG. 3 is a front view in the direction of arrows AA in FIG. 2, and FIG. 4 is a sectional view in the direction of arrows BB in FIG.

  As shown in these figures, the sensor unit 1 is mounted on a rotating shaft 116 fixedly supported on a support 111, and two wheels 112 that can be rotated separately from each other by bearings 112a provided on each of them, Insulator substrates (hereinafter simply referred to as substrates) 113 and 115 arranged between the wheels 112 and fixed horizontally to the rotation shaft 116 with the rotation shaft 116 interposed therebetween, and two spacers 114 for connecting the substrates 113 and 115 to each other. And are provided. Further, the sensor head 14 and the variable resistance element 13 are fixed to the lower surface side of the lower substrate 115. Further, the width of each peripheral surface of the wheel 112 is set to a predetermined width W. In this embodiment, the width W of the wheel 112 is set to 3 mm as an example.

  As shown in FIG. 5, the sensor head 14 has a magnetic sensor 10 fixed to the center of a cylindrical permanent magnet 15, and the substrate connecting the magnetic poles of the permanent magnet 15 perpendicular to the substrate 115. It is fixed to 115. The permanent magnet 15 is set so that the upper side is an N pole and the lower side is an S pole in the figure. Further, a gap D is formed between the lower end surface of the sensor head 14 fixed in this way and the lowermost end of the wheel 112. In this embodiment, the gap D is set to 0.5 mm as an example.

  In this embodiment, for example, an InSb (indium antimonide) magnetoresistive element is used as the magnetic sensor 10. The permanent magnet 15 is used for a magnetic bias, and its detection surface magnetic flux density is 850 G (Gauss) (S pole).

  When using the foreign matter detection device in a tire having the above-described configuration, the balance of the variable resistor 13 is adjusted before use, and the bridge circuit formed by the magnetoresistive elements 11 and 12 and the variable resistance element 13 is used. The output, that is, the differential voltage input to the differential amplifier 2 is set to be substantially zero.

  Next, by moving the sensor unit 1 with the lower end of the wheel 112 of the sensor unit 1 in contact with the tire to be inspected, a magnetic metal piece as a foreign object embedded near the surface layer of the tire can be easily obtained. Can be detected.

  That is, as shown in FIG. 6, when there is no magnetic metal piece in the vicinity of the sensor head 14, the magnetic flux entering and exiting both poles of the permanent magnet 15 passes through the magnetic sensor 10, and in this state, the bridge circuit is in an equilibrium state. The output voltage is 0. For this reason, since the output voltage of the differential amplifier 2 becomes substantially equal to 0, the determination circuit 3 determines that there is no magnetic metal piece. In this state, even if noise is mixed into the bridge circuit from the outside, this noise affects both the magnetoresistive elements 11 and 12 and the variable resistance element 13, so that they cancel each other and the noise from the bridge circuit. Since the output of the component is extremely small, the determination malfunction due to noise is extremely small. Therefore, the influence of external noise can be reduced, and more accurate detection can be performed.

  On the other hand, as shown in FIG. 7, when the magnetic metal piece 21 as a foreign object is embedded in the surface layer portion in the tire, when the magnetic metal piece 21 exists near the lower surface of the sensor head 14, the sensor head 14. Since the magnetic flux density inputted to the south pole of the permanent magnet 15 is reduced on the lower surface side of the magnet, the balanced state of the bridge circuit is lost and a voltage is generated at the output of the bridge circuit. This voltage is input to the differential amplifier 2 and amplified, and a voltage within the detection range is generated at the output of the differential amplifier 2. For this reason, the determination circuit 3 determines that the magnetic metal piece 21 is present, and notifies this.

  Further, in the foreign matter detection device having the above configuration, since the peripheral surface of the wheel 112 has a predetermined width W, even if foreign matter is detected in the green tire before vulcanization, the surface of the green tire is not damaged by the wheel. Foreign matter detection can be performed.

  Further, since each of the two wheels 112 can be individually rotated by the bearing 112a, the sensor unit 1 can be easily moved in a desired direction even if the tire surface has irregularities or inclinations.

  In addition, since the wheel 112 can move while keeping the distance (= gap D) between the tire surface and the sensor head 14 constant, it is possible to suppress a detection malfunction due to a change in the relative position between them. .

  Therefore, according to the foreign matter detection apparatus, it is possible to easily find a magnetic metal piece as a foreign matter embedded in the vicinity of the surface layer of the tire that is difficult to find by visual inspection by an inspector. Since it is possible to avoid the shipping of tires that are used as products, the quality of shipped products can be improved.

  In the above embodiment, the cylindrical permanent magnet 15 is disposed so as to surround the magnetic sensor 10 so that a minute magnetic field change due to the magnetic metal piece in the tire can be easily detected. However, a permanent magnet having a shape other than a cylindrical shape may be disposed in the vicinity of the magnetic sensor 10. In addition, if a DC electromagnet is provided instead of the permanent magnet 15 and this DC electromagnet is energized from the main unit 5 and the main unit 5 is provided with a means for changing the energization amount, the amount of current flowing through the electromagnet can be changed from the electromagnet. By changing the amount of magnetic flux generated, the depth at which foreign matter can be detected from the tire surface can be adjusted.

  Next, a foreign matter detection device in a tire according to Embodiment 2 of the present invention will be described. The electric circuit of the foreign object detection device in the second embodiment is the same as that in the first embodiment. In the second embodiment, the foreign object detection using the sensor unit 1A shown in FIGS. 8 to 10 in place of the sensor unit 1 in the first embodiment. Configured the device. 8 is a side view showing the sensor unit 1A, FIG. 9 is a plan view showing the sensor unit 1A, and FIG. 10 is a front view in the direction of arrows CC in FIG. In the figure, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the figure, reference numeral 1A denotes a sensor unit, which includes wheels 321 and 322 rotatably supported by support members 312 and 313 on the lower surface side of a substantially cross-shaped support substrate 311. These wheels 321 and 322 are provided such that their centers are located on a straight line that intersects with the rotation axes 323 and 324 at right angles. The support bodies 312 and 313 are fixed to the support substrate 311 with mounting screws 311c. In the present embodiment, the peripheral portions of the wheels 321 and 322 are substantially tapered.

  Further, a substrate 332 fixed to the support substrate 311 by two sets of mounting screws 311b and spacers 331 is provided between the two wheels 321 and 322, and the same magnetic sensor as in the first embodiment is provided on the lower surface side of the substrate 332. 14 is fixed, and the variable resistor 13 is fixed on the upper surface side of the substrate 332. Here, a gap D is formed between the lower end of the magnetic sensor 14 and the lowermost ends of the wheels 321 and 322.

  The support substrate 311 is provided with a wire drawing hole 311a, and a mounting plate 314 is fixed to the rear portion of the support substrate 311 by a fixing member 315 so as to protrude above the support substrate 311.

  As with the first embodiment, the foreign object detection device in the tire having the above configuration can easily find a magnetic metal piece as a foreign object embedded in the vicinity of the surface layer of the tire, which is difficult to find by visual inspection by an inspector. This makes it possible to avoid shipping as a tire product in which such foreign matter is embedded, so that the quality of the shipped product can be improved.

  In the sensor unit 1A, the two wheels 321 and 322 are provided so that their centers are located on a straight line that intersects with the rotation shafts 323 and 324 at right angles, and the peripheral portions of the wheels 321 and 322 are substantially tapered. Therefore, even if there are irregularities such as characters and marks formed on the surface like a vulcanized tire, it is easy to move the sensor unit 1A so as to avoid these irregularities. For this reason, the distance fluctuation | variation between the tire surface and the magnetic sensor 14 by such an unevenness | corrugation can be reduced, and a detection malfunction can be suppressed.

  Further, since the distance between the tire surface and the sensor head 14 (= gap D) can be kept constant by the wheels 321 and 322, it is possible to suppress a detection malfunction due to a change in the relative position between them.

  Therefore, even with the above foreign matter detection device, it is possible to easily find magnetic metal pieces as foreign matter embedded in the vicinity of the surface layer of the tire that are difficult to find by visual inspection by an inspector, and such foreign matter is embedded. Since it is possible to avoid shipping the tire as a product, the quality of the shipped product can be improved.

  Next, a foreign matter detection device in a tire according to Embodiment 3 of the present invention will be described. FIG. 11 is a configuration diagram illustrating a foreign matter detection device in a tire according to a third embodiment of the present invention. In the figure, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The difference between the third embodiment and the first embodiment is that in the third embodiment, a sensor unit 1B is provided instead of the sensor unit 1 in the first embodiment.

  The sensor unit 1B is provided with a magnetic sensor 40. The magnetic sensor 40 outputs a voltage of a predetermined value or more when a magnetic metal piece is present in the vicinity thereof. In this embodiment, an electromagnetic pickup is used as the magnetic sensor 40. Since this electromagnetic pickup is a self-power generation type, a driving power source is unnecessary, and the circuit configuration can be simplified. Each of the two output terminals of the magnetic sensor 40 is connected to the non-inverting input terminal and the inverting input terminal of the differential amplifier 2.

  The sensor unit 1B has a configuration shown in FIGS. Here, FIG. 12 is a front view of the sensor unit 1B, and FIG. 14 is a side view of the sensor unit 1B.

  As shown in these drawings, the sensor unit 1B has a vertical support plate 511, and a rotating shaft 512 protruding in the horizontal direction on one side is fixed to the lower end portion of the supporting plate 511. The wheel 513 is mounted so as to be rotatable by a bearing 514. Further, the magnetic sensor 40 is vertically fixed to the other surface side of the support plate 511 by an L-type support member 515, and a gap D is formed between the detection surface which is the lower end of the magnetic sensor 40 and the lowermost end of the wheel 513. Has been. In addition, two attachment holes 511a are provided in the upper end portion of the support plate 511. Further, the width of the peripheral surface of the wheel 513 is set to a predetermined width W as in the first embodiment.

  When using the foreign matter detection device in a tire having the above-described configuration, the sensor unit 1 is moved while the lower end of the wheel 513 of the sensor unit 1B is in contact with the tire to be inspected. A magnetic metal piece as a foreign substance embedded in the vicinity can be easily detected.

  That is, when there is no magnetic metal piece in the vicinity of the magnetic sensor 40, the output voltage of the magnetic sensor 40 is zero. For this reason, since the output voltage of the differential amplifier 2 becomes substantially equal to 0, the determination circuit 3 determines that there is no magnetic metal piece.

  On the other hand, when a magnetic metal piece is present near the magnetic sensor 40, a voltage is generated at the output of the magnetic sensor 40. This voltage is input to the differential amplifier 2 and amplified, and a voltage within the detection range is generated at the output of the differential amplifier 2. For this reason, the determination circuit 3 determines that the magnetic metal piece is present, and notifies this.

  In addition, since the wheel 513 can move while keeping the distance (= gap D) between the tire surface and the magnetic sensor 40 constant, it is possible to suppress a detection malfunction due to a change in the relative position between them. .

  Therefore, even with the above foreign matter detection device, it is possible to easily find magnetic metal pieces as foreign matter embedded in the vicinity of the surface layer of the tire that are difficult to find by visual inspection by an inspector, and such foreign matter is embedded. Since it is possible to avoid shipping the tire as a product, the quality of the shipped product can be improved.

  Next, a tire inspection apparatus according to Embodiment 4 of the present invention will be described. FIG. 14 is a configuration diagram illustrating a tire inspection apparatus according to the fourth embodiment. The tire inspection apparatus according to the present embodiment uses the foreign matter detection apparatus according to the first embodiment described above. In FIG. 14, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the tire inspection apparatus of this embodiment, the tire 70 to be inspected is rotated by the motor 61, and the rotation speed of the motor 61 is controlled by the rotation controller 62. Further, the sensor unit 1 has a movement controller 63 via a support member 63 a so that the wheel 112 rotates in the circumferential direction of the tire 70 with the lowermost end of the wheel 112 in contact with the surface of the tire 70. Is supported by

  The movement controller 63 moves the sensor unit 1 in the width direction of the tire 70 in a state where the lowermost end of the wheel 112 of the sensor unit 1 is in contact with the surface of the tire 70 in synchronization with the rotation of the tire by the rotation controller 62. Moving.

  In this embodiment, the determination circuit 3 is composed of a comparator and a counter circuit, and the frequency of the operation clock of the counter circuit is 40 KHz. Here, the comparator outputs a pulse signal when the output voltage of the differential amplifier 2 becomes a voltage within the detection range, and the counter circuit operates by the clock signal and inputs the pulse signal from the comparator. Count up.

  Thereby, when the outer peripheral length (measurement peripheral length) of the tire 70 is, for example, 2000 mm, when the strand having a diameter of 0.8 mm is embedded in the surface layer portion of the tire as a magnetic metal piece that is a foreign object, By setting the number of revolutions calculated from the equation (1), that is, the number of revolutions of the tire 70 to 1.0 rps, the presence of a buried strand can be detected.

0.8mm ÷ 2000mm × 40KHz × 0.6 ≒ 1.0rps (1)
Here, the constant 0.6 is a safety factor set in order to make it possible to reliably detect the twisted line.

  Further, when the strand having a diameter of 0.3 mm is embedded in the surface layer portion of the tire as a magnetic metal piece as a foreign object, the rotational speed calculated from the following equation (2), that is, the rotational speed of the tire 70 is set to 0. By setting the speed to .4 rps, it is possible to detect the presence of the buried strand.

0.3mm ÷ 2000mm × 40KHz × 0.6 ≒ 0.4rps (2)
Here, the constant 0.6 is the same safety factor as described above.

  By using the tire inspection apparatus described above, it is possible to automatically detect a magnetic metal piece as a foreign substance embedded in the surface layer portion in the tire.

  Therefore, according to the tire inspection apparatus described above, it is possible to automatically and easily find a magnetic metal piece as a foreign object embedded in the vicinity of the surface layer of a tire that is difficult to find by visual inspection by an inspector. Since it is possible to avoid shipping as a tire product in which foreign matter is embedded, the quality of the shipped product can be improved.

Next, a foreign matter detecting device in a tire in Example 5 of the present invention will be described. 15 is a side view showing a foreign matter detecting device in a tire according to Embodiment 5 of the present invention, FIG. 16 is a top view thereof, FIG. 17 is a plan view in the direction of arrows EE in FIG. 15, and FIG. FIG. 19 is a rear view thereof. In the figure, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Further, the difference between Example 5 and Example 1 is that Example 5 is provided with a mechanism capable of properly contacting the wheel with the tire surface in accordance with the state of the tire surface being curved or uneven. In the drawing, reference numeral 1C denotes a foreign matter detection device in the tire, which includes a wheel support portion 701, a swing mechanism portion 702, a swing mechanism portion 703, and a return mechanism portion 704.

  The wheel support portion 701 has an L-shaped member 630 made of two flat plates whose surfaces are connected at right angles, and has a vertical piece extending downward from the rear end of the horizontal piece of the L-shaped member 630. Further, the wheel support portion 701 is attached to the rotary shaft 116 fixedly supported on the support plates 629 fixed to both side surfaces of the flat plate arranged vertically on the L-shaped member 630, and attached to each of the rotary shafts 116. Two wheels 112 that can be rotated separately from each other by provided bearings, and an insulating substrate (hereinafter simply referred to as a substrate) that is disposed between these wheels 112 and is horizontally fixed to the rotating shaft 116 with the rotating shaft 116 interposed therebetween. 113, 115, two spacers 114 for connecting the substrates 113, 115, and a fixing pin 621 erected upward from the center of the front end of the horizontal piece of the L-shaped member 630.

  Further, the sensor head 14 and the variable resistance element 13 are fixed to the lower surface side of the lower substrate 115. Further, the width of each peripheral surface of the wheel 112 is set to a predetermined width W as in the first embodiment. In this embodiment, the width W of the wheel 112 is set to 3 mm as an example.

  As shown in FIG. 5, the sensor head 14 has the magnetic sensor 10 fixed to the center of the cylindrical permanent magnet 15 so that the straight line connecting the magnetic poles of the permanent magnet 15 is perpendicular to the substrate 115. It is fixed to the substrate 115. The permanent magnet 15 is set so that the upper side is an N pole and the lower side is an S pole in the figure. Further, a gap D is formed between the lower end surface of the sensor head 14 fixed in this way and the lowermost end of the wheel 112. In the present embodiment, like the first embodiment, the gap D is set to 0.5 mm as an example.

  The swing mechanism unit 702 includes the wheel support unit 701 described above and an L-shaped member 615 composed of two flat plates whose surfaces are connected to each other at a right angle, and downward from the rear end of the horizontal piece of the L-shaped member 615. It has a vertical piece that is extended. Further, the swing mechanism 702 has a long hole 624 that is curved at the front end of the horizontal piece of the L-shaped member 615, and the fixing pin 621 passes through the long hole 624. The springs 623 are connected to pins 622 erected on both ends. By these springs 623, the fixing pin 621 is maintained at the center of the long hole 624 in a steady state.

  Further, a rotation shaft 616 penetrating the horizontal piece is provided at the center of the horizontal piece of the L-shaped member 615, and the lower end portion thereof is fixed to the horizontal piece of the L-shaped member 630 of the wheel support portion 701. . Incidentally, a bearing or the like provided in the horizontal piece is covered with a lid 625 provided at the center of the upper surface of the horizontal piece of the L-shaped member 615, and the L-shaped member 615 and the L-shaped member 630 are rotated between the L-shaped member 615 and the L-shaped member 630. An annular washer 617 is provided so as to surround the periphery of the moving shaft 616. As a result, the wheel support portion 701 can rotate about the rotation axis 616 in the left-right direction by an angle corresponding to the elongated hole 624.

  The swing mechanism unit 703 has the above-described swing mechanism unit 702, a horizontal connecting plate 607, a bearing member 608 fixed to the lower surface of the connecting plate 607, and a rotating shaft 612 penetrating the bearing member 608. . A front end portion of the rotation shaft 612 is fixed to a vertical piece of the L-shaped member 615, and a vertical plate 614 is fixed to the rear end portion.

  In addition, a fixing pin 609 is provided at the upper back of the bearing member 608 so as to extend rearward. Further, the swinging mechanism portion 703 has an elongated hole 613 curved at the upper end of the vertical plate 614, and the fixing pin 609 passes through the elongated hole 613, and the fixing pin 609 is provided at each of both end portions of the elongated hole 613. It is connected to a pin 610 erected by a spring 611. By these springs 611, the fixing pin 609 is maintained at the center of the long hole 613 in a steady state.

  The return mechanism 704 includes the swing mechanism 703, a fixing member 601, a pair of support shafts 602, a bearing member 603, a cylinder 604, and the like.

  The fixing member 601 includes a horizontal bottom plate 601a, a vertical side plate 601b connected to the horizontal bottom plate 601a, and a pair of support plates 601c provided so as to support them. A cylinder 604 having a cylinder rod 605 is vertically fixed. Note that the cylinder 604 is a general one in which the cylinder rod 605 can be inserted and removed by a spring, air pressure, hydraulic pressure, or the like.

  Further, a bearing member 603 fixed to the horizontal bottom plate 601a of the fixing member 601 is provided on each of the front and rear sides of the cylinder rod 604, and a support shaft 602 that slides through the bearing member 603 and the horizontal bottom plate 601a. Is fixed to the connecting plate 607 by a fixing member 607a. The lower end of the cylinder rod 605 is fixed to the connecting plate 607 by a nut 606 and a boss 627.

  The electric foreign matter detection operation of the foreign matter detection device 1C in the tire having the above-described configuration is the same as that of the first embodiment. Further, as shown in FIGS. 20 and 21, in the foreign object detection device 1C of the present embodiment, the wheel support portion 701 can be rotated around the rotation shaft 616 by the swing mechanism portion 702, so that the surface of the tire The wheel support portion 701 can be rotated in accordance with the curved or uneven state, so that the two wheels 112 can always be kept in contact with the tire surface. As a result, even if the curvature or unevenness of the tire surface changes, the distance D between the sensor head 14 and the tire surface can be kept constant.

  Further, since the wheel support portion 701 can be rotated by the spring 623 and is held at a predetermined position in the rotation direction about the rotation axis 616, the wheel support portion 701 rotates and moves from the predetermined position in the rotation direction. When the external force applied to the wheel support portion 701 in the rotational direction is lost and the wheel support portion 701 is removed, the orientation of the wheel support portion 701 is steady so that the fixing pin 612 is positioned at the center of the elongated hole 623 by the spring 623. Return to position.

  Further, as shown in FIGS. 22 to 25, since the swing mechanism 702 including the wheel support 701 can be rotated around the rotation shaft 612 by the swing mechanism 703, the tire surface can be curved or The wheel support portion 701 can be rotated in accordance with the uneven state, and the two wheels 112 can always be kept in contact with the tire surface. As a result, even if the curvature or unevenness of the tire surface changes, the distance D between the sensor head 14 and the tire surface can be kept constant.

  Further, since the swing mechanism 702 including the wheel support 701 is rotatable by the spring 611, the wheel support 701 is rotated at a predetermined position in the rotation direction around the rotation shaft 612. When the external force applied to the wheel support portion 701 in the rotation direction is lost, the spring 611 swings the fixing pin 609 so that it is positioned at the center of the long hole 613. The mechanism unit 702 is returned to the steady position.

  Further, as shown in FIGS. 26 and 27, the swinging mechanism portion 703 is pressed in the vertical direction against the tire surface so that the wheel 112 is brought into contact with the tire surface with a predetermined pressure by the return / return mechanism portion 704. Therefore, the two wheels 112 can always be kept in contact with the tire surface corresponding to the curved or uneven state of the tire surface. As a result, even if the curvature or unevenness of the tire surface changes, the distance D between the sensor head 14 and the tire surface can be kept constant.

  As shown in FIG. 28, the foreign object detection device 1C fixes a fixing member 601 to a stitcher arm 801 or the like of a tire forming machine and uses the wheel 112 so as to contact the tire profile 802, thereby forming a tire. Since the tire inspection related to the foreign object detection can be performed subsequently or simultaneously, the inspection process can be simplified. Further, by attaching the foreign matter detection device 1C to the tire uniformity machine, the tire inspection related to the foreign matter detection can be performed following or simultaneously with the measurement of the tire uniformity, thereby simplifying the inspection process. Can be planned.

  The configurations of the first to fourth embodiments are specific examples of the present invention, and the present invention is not limited to the configurations of the above embodiments. For example, a magnetic sensor using a coil wound around an iron core or a known Hall element may be configured.

  Further, by adding a tire inspection device using the foreign matter detection device of each of the above embodiments to a well-known tire molding machine or tire uniformity machine, foreign matter in the tire can be inspected at the time of tire molding or testing. The inspection process can be simplified.

The block diagram which shows the foreign material detection apparatus in the tire in Example 1 of this invention The side view which shows the sensor unit in Example 1 of this invention AA arrow direction front view in FIG. BB sectional view taken along line BB in FIG. 1 is an external perspective view showing a magnetic sensor in Embodiment 1 of the present invention. The figure explaining operation | movement of the foreign material detection apparatus in Example 1 of this invention. The figure explaining operation | movement of the foreign material detection apparatus in Example 1 of this invention. The side view which shows the sensor unit in Example 2 of this invention The top view which shows the sensor unit in Example 2 of this invention The front view of the CC line arrow direction in FIG. The block diagram which shows the foreign material detection apparatus in the tire in Example 3 of this invention The front view which shows the sensor unit in Example 3 of this invention The side view which shows the sensor unit in Example 3 of this invention. The block diagram which shows the tire inspection apparatus in Example 4 of this invention The side view which shows the sensor unit in Example 5 of this invention. The top view which shows the sensor unit in Example 5 of this invention Plan view in the direction of arrows EE in FIG. The front view which shows the sensor unit in Example 5 of this invention The rear view which shows the sensor unit in Example 5 of this invention The top view explaining operation | movement of the swing mechanism part in Example 5 of this invention. The top view explaining operation | movement of the swing mechanism part in Example 5 of this invention. The front view explaining operation | movement of the rocking | fluctuation mechanism part in Example 5 of this invention. The rear view explaining operation | movement of the rocking | fluctuation mechanism part in Example 5 of this invention. The front view explaining operation | movement of the rocking | fluctuation mechanism part in Example 5 of this invention. The rear view explaining operation | movement of the rocking | fluctuation mechanism part in Example 5 of this invention. The side view explaining operation | movement of the withdrawal mechanism part in Example 5 of this invention. The side view explaining operation | movement of the withdrawal mechanism part in Example 5 of this invention. The figure which shows the example of mounting | wearing with the tire molding machine of the foreign material detection apparatus in Example 5 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,1A, 1B, 1C ... Sensor unit, 2 ... Differential amplifier, 3 ... Determination circuit, 4 ... Power supply, 10 ... Magnetic sensor, 11, 12 ... Semiconductor magnetoresistive element, 13 ... Variable resistance element, 14 ... Sensor head 15 ... Permanent magnet, 111 ... Support, 112 ... Wheel, 112a ... Bearing, 113, 115 ... Substrate, 114 ... Spacer, 116 ... Rotating shaft, 21 ... Magnetic metal piece, 311 ... Support substrate, 311a ... Wire extraction hole, 311b ... Mounting screw, 312,313 ... Support, 314 ... Mounting plate, 315 ... Fixing member, 321,322 ... Wheel, 323,324 ... Rotating shaft, 331 ... Spacer, 332 ... Substrate, 40 ... Magnetic sensor, 511 ... Support plate, 511a ... Attachment Hole, 512 ... rotating shaft, 513 ... wheel, 514 ... bearing, 61 ... motor, 62 ... rotation controller, 63 ... movement controller, 63a ... support member, 70 ... tire, 601 ... fixing member, 601a ... horizontal bottom plate, 601b ... Vertical side plate, 601c ... Support plate, 602 ... Support shaft, 60 4 ... Cylinder, 605 ... Cylinder rod, 606 ... Nut, 607 ... Connecting plate, 608 ... Bearing member, 609 ... Fixing pin, 610 ... Pin, 611 ... Spring, 612 ... Rotating shaft, 613 ... Long hole, 615 ... L Mold member, 616 ... Rotating shaft, 617 ... Washer, 621 ... Fixing pin, 623 ... Spring, 624 ... Long hole, 625 ... Lid, 627 ... Boss, 629 ... Support plate, 630 ... L-shaped member, 641 ... Vertical plate 701: Wheel support portion, 702: Swing mechanism portion, 703 ... Swing mechanism portion, 704 ... Retraction mechanism portion 704, 801 ... Stitcher arm, 802 ... Tire profile.

Claims (18)

A method for detecting foreign matter in a tire for detecting a magnetic metal piece that is a foreign matter in the vicinity of a surface layer in a tire from the outside of the tire,
Using a detection unit that outputs an electric signal in response to the magnetic metal piece present within a predetermined distance,
Detecting the presence of the magnetic metal piece, which is the foreign material, by a determination means comprising an electric circuit or a computer device based on the electric signal output from the detection unit moving at a certain distance from the surface of the tire. A method for detecting foreign matter in a tire, characterized by A method for detecting foreign matter in a tire for detecting a magnetic metal piece that is a foreign matter in the vicinity of a surface layer in a tire from the outside of the tire,
Using a detection unit that outputs an electrical signal that changes in accordance with the amount of change in the crossing magnetic flux, and a magnet that is disposed at a predetermined position in the vicinity of the detection unit,
On the basis of the electrical signal output from the detection unit moving at a certain distance from the tire surface in a state where the magnetic flux in one magnetic pole of the magnet intersects the tire surface and the detection unit, an electric circuit or A method for detecting a foreign matter in a tire, wherein the presence of the magnetic metal piece as the foreign matter is detected by a determination unit comprising a computer device. A foreign matter detection device in a tire that detects a magnetic metal piece that is a foreign matter embedded in the vicinity of a surface layer in a tire from the outside of the tire,
It has a sensor unit and a main unit,
The sensor unit is
A detector that outputs an electrical signal in response to the magnetic metal piece present within a predetermined distance;
The main unit is
An apparatus for detecting foreign matter in a tire, comprising: determination means for determining whether or not the magnetic metal piece is present based on an electric signal output from the detection unit and outputting the determination result. The detector is
A magnet disposed so that one magnetic pole is located at a predetermined distance from the surface of the tire and the magnetic flux in the one magnetic pole intersects the surface of the tire at the time of foreign object detection;
The magnetic sensor which is arrange | positioned so that it may cross | intersect the magnetic flux in said one magnetic pole while being arrange | positioned in the vicinity of the said magnet, and outputs the electrical signal corresponding to the quantity of crossing magnetic flux. Foreign matter detection device in tires. The foreign matter detection device in a tire according to claim 4, wherein the magnet has a cylindrical shape, and the magnetic sensor is disposed in the cylinder of the magnet so as to be surrounded by the magnet. The magnet is a DC electromagnet;
The said main unit has a direct current power source which supplies a direct current to the said direct current electromagnet, and a current variable means which changes the direct current amount supplied to the said direct current electromagnet. 6 or Claim 5 characterized by the above-mentioned. Foreign matter detection device in tires. The magnetic sensor includes first and second magnetoresistive elements that are arranged so as to intersect with the magnetic flux in the one magnetic pole, and the electric resistance value changes in accordance with the amount of the intersecting magnetic flux,
The sensor unit has at least one variable resistance element provided so as to form a bridge circuit together with the first and second magnetoresistance elements,
The main unit is
A power supply circuit for applying a voltage to two input terminals of the bridge circuit;
The determining means determines that the magnetic metal piece is present when the value of the voltage output from the two output terminals of the bridge circuit is greater than a predetermined reference value, and outputs a determination result. The foreign matter detection device in a tire according to any one of claims 4 to 6, wherein the foreign matter detection device in a tire is provided. The said sensor unit has a wheel which abuts on the surface of the said tire, rotates, and can move the said one magnetic pole or the said detection part at a fixed distance from the surface of the said tire. The foreign matter detection device in a tire according to any one of claims 7 to 9. The tire according to claim 8, wherein the sensor unit includes two wheels having a rotation axis on the same straight line and capable of rotating separately from each other and having a circumferential surface width equal to or greater than a predetermined value. Inside foreign matter detection device. The foreign matter detection device in a tire according to claim 8, wherein the sensor unit includes two wheels whose rotation centers are located on the same straight line and whose rotation axes are parallel to each other. A foreign matter detection device in a tire that detects a magnetic metal piece that is a foreign matter embedded in the vicinity of a surface layer in a tire from the outside of the tire,
It has a sensor unit and a main unit,
The sensor unit is
A detector that outputs an electrical signal in response to the magnetic metal piece present within a predetermined distance;
It has a rotation axis on the same straight line and can be rotated separately from each other, rotate in contact with the surface of the tire, and move the detection unit at a predetermined distance above the tire surface while maintaining a certain distance. Two wheels having a circumferential width;
A swing mechanism that has a rotation axis that is orthogonal to the rotation axis of the wheel and that is parallel to the tire surface, and that supports a wheel support portion that supports the two wheels so as to be rotatable about the rotation axis. And
The main unit is
An apparatus for detecting foreign matter in a tire, comprising: determination means for determining whether or not the magnetic metal piece is present based on an electric signal output from the detection unit and outputting the determination result. The foreign matter detection device in a tire according to claim 11, further comprising holding means for holding the wheel support portion at a predetermined position in a rotation direction centering on the rotation axis in a rotatable state. . The sensor unit has a second rotation axis that is perpendicular to the rotation axis of the wheel and perpendicular to the tire surface, and a wheel support portion that supports the two wheels can rotate about the rotation axis. The apparatus for detecting foreign matter in a tire according to claim 11, further comprising: The inside of the tire according to claim 13, further comprising second holding means for holding the wheel support portion at a predetermined position in a rotation direction around the second rotation axis in a state where the wheel support portion is rotatable. Foreign object detection device. The sensor unit has a fixing portion that fixes the entire unit to another member, and the fixing portion moves the swing mechanism portion to the surface of the tire so that the wheel contacts the surface of the tire with a predetermined pressure. A foreign matter detecting device in a tire according to any one of claims 11 to 14, further comprising a return-and-return mechanism portion that presses in a vertical direction relative to the tire. A tire inspection device for detecting unnecessary magnetic metal pieces embedded in the vicinity of a surface layer in a tire to be inspected,
Rotating means for rotating the tire to be inspected;
A foreign matter detecting device in a tire according to any one of claims 3 to 15,
A tire inspection apparatus comprising means for holding the detection unit of the magnetic body detection apparatus at a position at a predetermined distance from the surface in the inspection region of the tire.   A tire molding machine comprising the tire inspection device according to claim 16.   A tire uniformity machine comprising the tire inspection device according to claim 16.

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