JP2009020081A - Deformation measuring method and deformation measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply improve the measurement precision and reproducibility at the time of measuring deformation. <P>SOLUTION: On a supporting sheet 18 fixed on a tire 11, a first support 21 provided with magnets 22 and 23, and a second support 26 provided with Hall elements 30 and 31 are fixed separately, and also a cushion layer 35 is interposed between the second support 26 and a support sheet 18 so as to enlarge the size, therefore, the fixing location or direction can be easily changed into a specified location and direction. Thereby, the measurement precision and the reproducibility can be easily improved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

    The present invention relates to a deformation measuring method and a deformation measuring device for measuring deformation of a measured object, for example, a pneumatic tire.

As a conventional deformation measuring method and deformation measuring apparatus, for example, those described in Patent Document 1 below are known.
JP 2002-002472 A

  This is a resistance wire strain gauge affixed to the inner periphery of the tread portion of a pneumatic tire, and the resistance change of the metal wire when the resistance wire of the strain gauge expands and contracts following the deformation (strain) of the tread portion. And a measurement unit for determining the deformation of the tread portion, and measuring the deformation of the tread portion based on the wiping deformation of the pneumatic tire.

    However, in such a conventional deformation measuring method and deformation measuring instrument, since the strain gauge is thin and small, about several mm square, the position and orientation of the strain gauge are attached to the specified position and orientation. As a result, there is a problem that the accuracy and reproducibility of the measurement results are lowered.

  An object of this invention is to provide the deformation | transformation measuring method and deformation | transformation measuring device which can improve a measurement precision and reproducibility easily.

    The first object is to provide a first support body provided with a magnet and a second support body provided with a Hall element for detecting a distance between the magnet and a position separated from the first support body. Is fixed, and a cushion layer made of a material having a smaller elastic coefficient than itself is interposed between the first support body and the second support body, and expands and contracts following the deformation of the measured object. It can be achieved by a deformation measuring method comprising a step of fixing a support sheet that can be deformed to a deformed object to be deformed, and a step of obtaining deformation of the object to be measured based on a detection result from the Hall element. .

  Secondly, a support sheet that is fixed to the measurement object at the time of measuring deformation of the measurement object and that can expand and contract following the deformation of the measurement object, and a magnet that is fixed to the support sheet and provided with a magnet are provided. A first support member, a second support member fixed to a support sheet at a position spaced from the first support member, and provided with a Hall element for detecting a distance between the first support member and the first support member; Or a cushion layer made of a material having a smaller elastic coefficient than that of the support sheet, interposed between either one of the second supports and the support sheet, and based on the detection result from the Hall element, This can be achieved by a deformation measuring device adapted to determine the deformation.

  In this invention, the first support body provided with the magnet on the support sheet and the second support body provided with the hall element are separated and fixed, and a cushion layer is provided between any one of these and the support sheet. As a whole, it becomes larger than the conventional strain gauge, and as a result, the fixing position and orientation can be easily set to the specified position and orientation, and the accuracy and reproducibility of measurement results can be improved easily. it can.

  In the present invention, when the support sheet expands and contracts following the deformation of the measured object, the first or second support without the cushion layer is displaced by the same amount as the support sheet. The remaining first or second support provided with the cushion layer has a displacement amount approaching zero because the cushion layer absorbs deformation. As a result, the distance between the first and second supports, specifically the distance between the magnet and the Hall element, changes. The distance detected by the Hall element at this time, that is, the deformation of the measured object based on the detection result. Ask for.

  In addition, if the Hall element and the measurement part are both provided on the second support body as described in claim 3, a situation in which the signal line connecting the two is disconnected due to the deformation of the tire is suppressed, whereby the measurement is performed. The interruption of work can be effectively suppressed. Furthermore, if configured as described in claim 4, the deformation of the measured object in a desired direction can be easily measured with high accuracy, and if configured as described in claim 5, Measurement can be easily performed in a state where the deformation of the measuring body is disassembled in two orthogonal directions. Further, if configured as described in claim 6, the support sheet can be manufactured easily and inexpensively, and if configured as described in claim 7, it is inexpensive but sufficiently absorbs deformation. can do.

Embodiment 1 of the present invention will be described below with reference to the drawings.
In FIG. 1, reference numeral 11 denotes a pneumatic radial tire as a body to be measured that is mounted on, for example, a passenger car, a truck, a bus, and the like. The tire 11 has a tread portion 13 that contacts a road surface 12 during traveling. A plurality of main grooves 14 that are wide and continuously extend in the circumferential direction, and wide lateral grooves 15 that extend in the width direction and intersect the main grooves 14 are formed on the outer periphery of the portion 13. In some cases, only one of the main groove 14 and the lateral groove 15 is formed on the outer periphery of the tread portion 13. When such a tire 11 is run under a load, various external forces act on the tread portion 13 in the ground contact region to expand and contract in at least one of the width direction and the circumferential direction, and deformation occurs.

  17 is a deformation measuring device installed on the inner periphery of the tire 11 (tread portion 13). The deformation measuring device 17 is a deformation in the width direction and the circumferential direction on the inner periphery of the tread portion 13 based on the external force as described above. Is disposed on the inner periphery of the tread portion 13. The deformation measuring instrument 17 has a rectangular sheet-like support sheet 18 that is detachably fixed to the tire 11 (inner periphery of the tread portion 13) with an adhesive or the like, as shown in FIGS. The support sheet 18 is thin and has a constant thickness, and can expand and contract by the same amount in the same direction following the deformation of the tire 11 (tread portion 13).

  As a result, the support sheet 18 expands and contracts in the width direction and the circumferential direction following the deformation of the tire 11 (tread portion 13) every time the deformation measuring instrument 17 reaches the ground contact region by the rotation of the tire 11. When the external force is no longer applied away from the ground contact area, the original shape (length) is restored. Here, since the support sheet 18 described above is made of vulcanized rubber, it can be easily and inexpensively manufactured.

  Reference numeral 21 denotes a first support body whose base end (outer end) is directly fixed to the central portion of the support sheet 18 and extends in the radial direction toward the rotation axis of the tire 11, and the first support body 21 is substantially cylindrical. And is made of a rigid body such as plastic. A plurality of, in this case, two magnets 22 and 23 used for measuring the deformation in the width direction and the circumferential direction described above are embedded in the first support 21, and the magnets 22 are embedded in the width direction of the tire 11. On the other hand, the magnet 23 extends in the circumferential direction of the tire 11. The magnets 22 and 23 may be provided on the first support 21 by being fixed to the surface of the first support 21 or by being partially embedded in the first support 21.

  Here, the magnet 22 described above is disposed on the distal end side (radially inside) of the magnet 23 and is orthogonal to the magnet 23. It should be noted that only one magnet may be provided when measuring only one direction of deformation of the tire 11, but only one is possible when measuring deformation in a plurality of directions. As described above, it is preferable to provide two or three or more. And when providing a some magnet in this way, it is preferable to arrange | position these magnets, making them cross | intersect at equal angles. Further, as the magnets 22 and 23, permanent magnets such as ferrite magnets can be used.

  Reference numeral 26 denotes a second support body made of a rigid body, for example, plastic, and fixed to the support sheet 18. The first support body 21 coaxial with the first support body 21 is provided at the center of the second support body 26. A larger-diameter through hole 27 extending in the radial direction is formed. The first support 21 is inserted into the through-hole 27. As a result, the second support 26 is located at a position where the inner periphery of the through-hole 27 is separated from the first support 21 by an equal distance. This means that the first support 21 can be displaced independently of the second support 26 by being fixed to the support sheet 18.

  30 and 31 are rectangular plate-shaped hall elements embedded in the second support body 26 in the vicinity of the through-hole 27, and the hall element 30 is disposed on the extension line of the magnet 22 so as to be orthogonal thereto, The hall elements 31 are arranged on the extension line of the magnet 23 so as to be orthogonal thereto, and as a result, the hall elements 30, 31 are arranged 90 degrees apart in the circumferential direction with the first support 21 as the center. It will be. The Hall elements may be provided in the same number on one side corresponding to the magnets as described above, or may be provided on both sides in a double number. It is preferable to arrange on the extension line of the magnet so as to be orthogonal thereto.

  Here, the Hall elements 30, 31 are made of a semiconductor material such as Ge, Si, and the magnitude of the magnetic field acting in a direction perpendicular to the Hall elements 30, 31 when a constant current is passed through the input terminals thereof. Can be output from the output terminal. Then, following the deformation in the width direction and the circumferential direction of the tire 11 (tread portion 13), the support sheet 18 expands and contracts by the same amount in the same direction, whereby the Hall elements 30, 31 and the magnets 22, 23 When the distance between them changes as will be described later, the magnitude of the magnetic field acting on the Hall elements 30 and 31 changes in accordance with the change in the distance, and the output voltage (detection result) changes. The deformation in the width direction and the circumferential direction of the (tread portion 13) is measured.

  Further, as described above, if a plurality (two) of the Hall elements 30 and 31 are arranged 90 degrees apart in the circumferential direction, the deformation of the tire 11 (tread portion 13) is orthogonal without performing complicated calculations. It can be easily measured in a state of being decomposed in two directions. In addition, when installing a plurality of Hall elements, these Hall elements can be arranged apart from each other in the circumferential direction by an angle other than 90 degrees. In this case, the outputs from the plurality of Hall elements (detection results) ), The deformation of the tire 11 (tread portion 13) in a desired direction can be easily measured with high accuracy, and the effect becomes more prominent as the number of Hall elements increases.

  Reference numeral 35 denotes a cushion layer interposed between the second support 26 and the support sheet 18, and the second support 26 is indirectly fixed to the support sheet 18 by interposing this cushion layer 35. Will be. The cushion layer 35 is made of a material having a smaller elastic coefficient than the support sheet 18. As a result, when the support sheet 18 expands and contracts following the tire 11 (tread portion 13), the cushion layer 35 is supported by the support sheet 18. As a result, the amount of displacement of the second support 26 approaches zero. Here, it is preferable that the cushion layer 35 is made of a synthetic sponge such as a urethane foam that is porous, because the deformation can be sufficiently absorbed while being inexpensive.

  Reference numeral 38 denotes a measurement unit embedded in the base end portion of the second support 26, and the measurement unit 38 is configured by a control board such as an IC chip. The measurement unit 38 and the Hall elements 30, 31 are connected by signal lines 39, 40 embedded in the second support 26, and outputs (detection) from the Hall elements 30, 31 through these signal lines 39, 40. Result) is sent to the measuring unit 38. When the outputs from the Hall elements 30 and 31 are sent to the measurement unit 38 in this way, the measurement unit 38 performs a calculation based on the detection result from the Hall element 30 to deform the tire 11 (tread portion 13) in the width direction. Further, calculation is performed based on the detection result from the Hall element 31 to obtain the deformation in the circumferential direction.

  Specifically, the average value of the distance between the Hall elements 30, 31 and the magnets 22, 23 when the deformation measuring instrument 17 is located outside the grounding area is obtained and stored as a reference value in the measuring unit 38. When the distance between the Hall elements 30, 31 and the magnets 22, 23 changes when the deformation measuring instrument 17 reaches the grounding region, the changed distance is detected and compared with the reference value, Thereby, the deformation in the width direction and the circumferential direction in the tire 11 (tread portion 13) is measured.

    As described above, the first support 21 provided with the magnets 22 and 23 on the support sheet 18 and the second support 26 provided with the Hall elements 30 and 31 are separated and fixed, and the second support 26 is provided. Since the cushion layer 35 is interposed between the support sheet 18 and the support sheet 18, the overall size is larger than the conventional strain gauge. As a result, the fixing position and orientation can be easily set to the specified position and orientation, and the measurement results Accuracy and reproducibility can be easily improved. In addition, since the Hall elements 30, 31, and the measurement unit 38 are both provided on the second support 26, the situation where the signal lines 39, 40 connecting both are disconnected due to deformation of the tire 11, is suppressed. The interruption of the measurement work can be effectively suppressed.

Next, the operation of the first embodiment will be described.
When measuring the deformation of the tire 11 (tread portion 13) using the deformation measuring instrument 17 described above, an adhesive or the like is used on the inner periphery of the tire 11 (tread section 13) to support the deformation measuring instrument 17. Removably fix 18 Next, after the tire 11 is mounted on the rim and filled with the internal pressure, the tire 11 is run on the road surface 12 while being loaded with a predetermined load, and is rotated a plurality of times. At this time, based on the measurement results from the Hall elements 30, 31, the Hall element 30, 31 when the deformation measuring instrument 17 is located outside the grounding region using the measuring unit 38 (when no external force is applied) An average value of distances between the magnets 22 and 23 is obtained and stored in the measurement unit 38 as a reference value. The reference value may be stored in the measurement unit 38 as a preset value.

  Next, when the tire 11 is run again and the deformation measuring instrument 17 reaches the ground contact area, the inner periphery of the tread portion 13 and the support sheet 18 expand and contract in the width direction and the circumferential direction following the expansion and contraction of the tire 11. At this time, since the cushion layer is not provided between the first support 21 and the support sheet 18, the first support 21 is displaced by the same amount as the support sheet 18, but the second support 26 and the support sheet 18 are supported. Since the cushion layer 35 is interposed between the seat 18 and the seat 18, the cushion layer 35 absorbs the deformation of the support sheet 18, and the displacement amount of the second support 26 approaches zero.

  Due to such displacement of the first and second supports 21 and 26, the distance between the first and second supports 21 and 26, specifically, the distance between the magnets 22 and 23 and the Hall elements 30 and 31 changes. However, the changed distances are detected by the Hall elements 30 and 31 and output to the measurement unit 38 as a detection result (output voltage). At this time, the measurement unit 38 compares the detection result (distance) with a reference value, and determines the deformation in the width direction and the circumferential direction of the tire 11 (tread portion 13) from these comparison results. The deformation of the tire 11 (tread portion 13) measured in this way is read from the measurement portion 38 by, for example, a reader installed outside the tire 11 by wireless communication. Further, based on the detection results from the Hall elements 30 and 31 described above, an input value to the tire 11 or an integrated rotation speed of the tire 11 can be obtained.

    In the above-described embodiment, the deformation measuring device 17 is installed on the inner periphery of the tire 11 (tread portion 13). However, in the present invention, it may be installed on the sidewall portion of the tire, or It may be installed on a member other than a tire, such as a conveyor belt or a seismic isolation rubber, and the deformation may be measured. In the above-described embodiment, the cushion layer 35 is interposed only between the support sheet 18 and the second support body 26. However, in the present invention, the support sheet 18, the first support body 21, Even if the cushion layer is interposed only between the two, deformation can be measured in the same manner.

  The present invention can be applied to the industrial field for measuring deformation of a measured object, for example, a tire.

It is sectional drawing of the tread part in the width direction which shows Embodiment 1 of this invention. It is a perspective view of a deformation measuring instrument vicinity. FIG. FIG. 4 is a cross-sectional view taken along the line II in FIG. 3.

Explanation of symbols

11 ... Measured object 18 ... Support sheet
21 ... 1st support body 22, 23 ... Magnet
26 ... Second support 30, 31 ... Hall element
35… Cushion layer 38… Measurement part

Claims (7)

    A first support provided with a magnet and a second support provided with a Hall element for detecting a distance between the magnet and a position spaced apart from the first support are fixed, and the first support Alternatively, a cushion layer made of a material having a smaller elastic modulus than that of the second support body is interposed between the second support body and the support sheet that can expand and contract following the deformation of the measured body. A deformation measuring method comprising: a step of fixing to a measuring body; and a step of obtaining a deformation of the body to be measured based on a detection result from the Hall element.     A support sheet that is fixed to the measurement object at the time of deformation measurement of the measurement object and that can expand and contract following the deformation of the measurement object; a first support sheet that is fixed to the support sheet and provided with a magnet A second support provided with a Hall element for detecting a distance between the support and a support sheet at a position separated from the first support and detecting a distance between the magnet and the first support or the second support; A cushion layer made of a material having a smaller elastic coefficient than that of the support sheet and interposed between any one of the bodies and the support sheet, and determining deformation of the measured object based on the detection result from the Hall element Deformation measuring device characterized by that.     The deformation measuring instrument according to claim 2, wherein a measuring unit for obtaining deformation of the measured object based on a detection result from the Hall element is provided on the second support.     The deformation measuring instrument according to claim 2 or 3, wherein a plurality of the hall elements are arranged circumferentially around the magnet.     The deformation measuring instrument according to claim 4, wherein the plurality of hall elements are arranged 90 degrees apart in the circumferential direction.     The deformation measuring instrument according to claim 1, wherein the support sheet is made of vulcanized rubber.     The deformation measuring instrument according to claim 1, wherein the cushion layer is made of a synthetic sponge.

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