JP5550529B2 - Method for measuring the inner shape of tire molds - Google Patents

Description

The present invention relates to an inner surface shape measuring how the tire mold. More particularly, it relates to how reference to the reference diameter portion provided on the widthwise ends of the tire mold, for measuring the shape of the mold inner surface.

  When manufacturing a tire, a plurality of types of tire components are combined to form a so-called raw tire, and then a raw tire is formed on a tire molding mold in which a pattern such as a tread pattern provided on the vulcanizer is formed on the inner surface. Is set and vulcanized. As a mold type using a mold for molding a tire in such a vulcanization process, a two-piece mold type using a mold divided into two in the width direction of the tire, an upper mold and a lower mold arranged on both sides in the tire width direction. A sectional mold type using a mold divided into 7 to 13 pieces in the circumferential direction of the mold and the tire has been put into practical use.

  The mold for tire molding has a structure in which the design surface that forms a pattern such as a tread pattern is complicated and has a structure in which a high-strength thin-walled member (sipe blade) is fitted, so it is not manufactured by machining, but by a casting method. Often manufactured. In the casting manufacturing method, a model is first created by machining, a rubber mold and a mold are sequentially created by a casting transfer method corresponding to the created model, and a casting is produced using the created mold. By adopting the casting method, it is easy to form pin corners and protrusions that are difficult to machine, and it is easy to form R-shaped projections. it can.

  In mold manufacturing by such casting method, deterioration of dimensional accuracy that occurs in the process by casting transfer method becomes a problem, so the roundness check of the inner surface of the mold and the correction of the inner surface shape are performed in each step of the manufacturing process. There are many cases. In the case of a sectional mold type mold, the mold is divided in the circumferential direction, so it is difficult to set a standard for measuring the radial distance, roundness, etc. There was a problem that it was difficult to position and fix.

  Regarding the measurement technique of the radial distance and roundness regarding the sectional mold type mold, for example, Patent Documents 1 and 2 disclose that the divided tread segment of the tire vulcanization mold is cylindrical as in the operating state. The measuring means equipped with a non-contact sensor are attached with reference to the outer peripheral surface of the mold and the bottom of the holding body, and the center of the mold arranged in a cylindrical shape and the center of the measuring means are coaxial. It is described that the inner surface unevenness of the tread segment is measured by moving the non-contact sensor in the radial direction and the circumferential direction and measuring the radial distance from the center. Patent Document 3 describes a three-dimensional measurement method for measuring a surface shape of an object to be measured while setting the object to be measured on a measuring table and rotating the measuring table and contacting a probe. Document 4 describes a method of measuring roundness by detecting irregularities in the radial direction of the surface of the object to be measured while bringing the detector into contact with the surface of the object to be measured.

JP 2002-257537 A JP 2006-289902 A JP 2005-326344 A Japanese Patent Laid-Open No. 2007-113947

  Each of the measurement methods described in each of the above-mentioned patent documents has a problem that a measuring instrument becomes large and it takes time to position and fix the object to be measured at the start of measurement. Also, when measuring the inner surface shape of a mold for molding a tire, part or all of the outer peripheral surface of the mold must be machined to improve accuracy, and the inner surface shape must be measured based on the machined surface. However, there is a problem that it takes time and effort. In other words, when a casting mold is used as a tire molding mold, the inner surface shape cannot be measured in a so-called “as-cast” (cast-up state), so it is necessary to perform measurement by forming a reference surface by machining. is there.

  In the tire molding die, the required dimensional accuracy is about 0.1 mm. Therefore, the resolution required for measurement with that accuracy may be about 0.01 mm. This has a large tolerance for accuracy compared to general accuracy finishing (μm order), but there is currently no simple measurement method corresponding to the level of finishing accuracy of such a mold for tire molding.

  Accordingly, an object of the present invention is to provide a measurement method that can accurately measure the inner surface shape of a tire molding die using a simple measurement jig.

  In the method for measuring the inner surface shape of a tire molding die according to the present invention, a support pin that is positioned based on a reference radius along a radial direction from an axis shaft that is a measurement central axis is set on the inner surface of the tire molding die. Contacting the reference diameter portion to support the shaft shaft, contacting a measuring tool positioned on the basis of a set radius along the radial direction from the shaft shaft, and contacting the measurement surface of the tire molding die, The shape of the surface to be measured is measured by moving the measuring tool in the axial direction and / or circumferential direction of the measurement center axis. Furthermore, the measuring tool measures a difference between a measurement radius to the contact point of the surface to be measured and the set radius. Further, the support pin is positioned based on a temporary reference radius and brought into contact with the reference diameter portion to support the shaft shaft, and the measuring tool positioned based on the set radius is brought into contact with the surface to be measured. A difference value between a measurement radius to a contact point and the set radius is measured, and the reference radius is set based on the measured difference value and the temporary reference radius.

  The present invention uses a support pin and a measurement tool that are positioned with respect to an axis shaft that is a measurement center axis, and the support pin is brought into contact with a reference diameter portion to support the shaft shaft so that the measurement tool is used for a tire molding die. Since the shape of the surface to be measured is measured by bringing the measuring tool into contact with the surface to be measured and moving the measuring tool in the axial direction and / or the circumferential direction of the measurement center axis, measurement can be performed with a simple measurement jig. Even in the case of a cast product or an as-cast semi-processed product, the measurement surface of the mold can be easily measured. Therefore, it is possible to evaluate the dimensional accuracy of the processed product before finishing and to optimize the positioning specifications when performing machining, which can contribute to improving the dimensional accuracy of the tire molding die.

FIG. 1A is a front view and FIG. 1B is a side view of a measuring jig used in the method for measuring the inner surface shape of a tire molding die according to the present invention. It is explanatory drawing regarding the inner surface shape measuring method of the metal mold | die for tire shaping | molding. It is explanatory drawing regarding the measurement procedure using a measuring jig, FIG. 3A is a front view, FIG. 3B is a side view. It is explanatory drawing regarding the measurement procedure using a measuring jig, FIG. 4A is a front view, FIG. 4B is a side view. It is explanatory drawing regarding the measurement procedure using a measuring jig, FIG. 5A is a front view, FIG. 5B is a side view. It is explanatory drawing regarding the measurement procedure using a measurement jig. It is explanatory drawing regarding the measurement procedure using a measurement jig. It is explanatory drawing regarding the setting procedure of the measurement jig | tool when the reference | standard radius of a metal mold | die is unknown, FIG. 8A is a front view, FIG. 8B is a side view. It is explanatory drawing regarding the setting procedure of the measurement jig | tool when the reference | standard radius of a metal mold | die is unknown, FIG. 9A is a front view, FIG. 9B is a side view. FIG. 10A is a front view and FIG. 10B is a side view illustrating a procedure for setting a measurement jig when the reference radius of a mold is unknown. FIG. 11A is a front view and FIG. 11B is a side view illustrating a procedure for setting a measuring jig when the reference radius of a mold is unknown. It is explanatory drawing regarding the setting procedure of the measurement jig | tool when the reference | standard radius of a metal mold | die is unknown, FIG. 12A is a front view, FIG. 12B is a side view. It is a perspective view regarding the example which the deformation | transformation of the width direction of the tire produced in the to-be-measured surface of the metal mold | die. It is a perspective view regarding the example which the deformation | transformation of the circumferential direction produced in the to-be-measured surface of the metal mold | die. It is a perspective view regarding the example which the twist generate | occur | produced in the metal mold | die. It is a dimension figure about the shape of a metallic mold. It is a graph which shows a measurement result. It is a graph which shows a measurement result.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view (FIG. 1A) and a side view (FIG. 1B) relating to a measuring jig used in the method for measuring the inner surface shape of a tire molding die according to the present invention. The measurement jig is rotated around the shaft shaft 1 between the shaft shaft 1 serving as a measurement center axis, a pair of support frames 2 (not necessarily limited to a pair) that are rotatably attached to the shaft shaft 1, and the support frame 2. And a rotatable arm 3 that is movably attached.

  The support frame 2 is formed in a sector shape, and a pair of radius portions 20 are extended from the center of the sector shape at a predetermined center angle, and the tips thereof are connected by an arc portion 21. A mounting hole 22 is formed at the center of the sector, and a set screw 23 for fixing the shaft 1 to the mounting hole 22 is screwed. The end portion of the shaft shaft 1 can be inserted into the mounting hole 22 and fixed with a set screw 23 at an appropriate position in the axial direction and circumferential direction of the shaft shaft 1. In a state where the support frame 2 is fixed to the shaft shaft 1, the radius portion 20 of the support frame 2 is set along the radial direction so as to be orthogonal to the center axis T of the shaft shaft 1, and the arc portion 21 is the center axis T. It is set to match the circumferential direction.

  The arc portion 21 of the support frame 2 is formed to be thicker than the radius portion 20 and has a shape protruding inwardly in a step shape. A plurality of support holes 21 a for inserting the support pins 4 are formed in the projecting portion of the arc portion 21 in a step shape, and the support holes 2 are fixed to the shaft shaft 1 in the state where the support frame 2 is fixed to the shaft shaft 1. The support hole 21a is precisely drilled so that the axial direction of the support pin 4 inserted into 21a matches the radial direction of the central axis T. The support holes 21a are provided at positions where the center lines that bisect the fan-shaped central angle of the support frame 2 intersect, and a plurality of pairs of support holes 21a that are paired at positions that are symmetrical with respect to the center line. Is provided.

  The support pin 4 is formed in a round bar shape with a tip end pointed in a conical shape. The support pin 4 is inserted into a hole of the bush 40 inserted in the support hole 21a in advance, and the tip end portion is directed outward in the radial direction. And are attached so as to protrude from the arc portion 21. The bush 40 is inserted into a hole formed inside the portion of the arc portion 21 where the support hole 21a is formed, and is set in the support hole 21a. Then, a set screw 41 screwed into the support hole 21a from the opposite side to the bush 40 is pressed against the bush 40, and the support pin 4 is fixed at a predetermined position. A compression spring 42 is inserted into the tip portion protruding outward from the arc portion 21, and a retaining member 43 of the compression spring 42 is fixed to the tip portion by a set screw on the further outside of the compression spring 42. ing. Since the compression spring 42 acts to press the retaining member 43 outward, the support pin 4 is pulled outward. As will be described later, when the support pin 4 is positioned, the tip of the support pin 4 comes into contact with the positioning jig. At this time, the support pin 4 is pushed into the support hole 21 a by the pressing force of the compression spring 42. It can be in a stable state so as not to move inadvertently.

  The rotating arm 3 is an elongated frame body in which a narrow linear groove 3 a is formed over the entire length, and a central portion is fixed to a rotating portion of the rotor 30 by a pair of mounting bolts 31. The rotor 30 includes a rotating portion attached to a fixed portion fixed to the shaft shaft 1 with a set screw 32 via a ball bearing, and the rotating portion is rotatable about the central axis T. Yes. With the rotor 30 attached to the shaft 1, the longitudinal direction of the linear groove 3 a of the rotary arm 3 is set to a direction orthogonal to the central axis T of the shaft 1. And by loosening the attachment bolt 31, it becomes movable in the orthogonal direction and can be positioned at an appropriate position.

  A dial gauge 5 as a measuring tool is attached to the tip of the rotary arm 3 on the same side as the support frame 2. In the dial gauge 5, a mounting bolt 51 having a sleeve 50 inserted in a mounting hole on the back surface is inserted, and the tip of the mounting bolt 51 is inserted into the linear groove 3 a of the rotating arm 3 and fixed by a mounting nut 52. Yes. The dial gauge 5 is adjusted between the rotary arm 3 by adjusting the length of the sleeve 50 so that the operation direction of the measuring spindle 5 a provided so as to protrude outward matches the radial direction of the central axis T. An interval is set. Since the dial gauge 5 is attached as described above, when the rotary arm 3 rotates around the shaft shaft 1, the dial gauge 5 rotates along the circumferential direction of the central axis T of the shaft shaft 1. Further, by loosening the mounting bolt 31, the rotary arm 3 can be moved along the linear groove 3 a, and the dial gauge 5 can be positioned at an appropriate position in the radial direction of the central axis T. Then, by loosening the set screw 32 for fixing the rotor 30, the rotor 30 can move on the shaft 1 along the central axis T, and can be positioned at an appropriate position along the central axis T. .

  FIG. 2 is an explanatory diagram related to a method for measuring the inner surface shape of a mold M for molding a tire. In this example, the mold M is one of sectional molds of the sectional mold type. The inner surface of the mold M corresponding to the outer periphery of the tire has both side portions in the width direction of the tire projecting inwardly in a step shape, and the central portion is shaped as a design surface that forms a pattern such as a tread pattern. . In this measurement method, both side portions are set as reference diameter portions S1 and S2, and the design surface is set as a measured surface S3. In the reference diameter portion S1, a reference line is set so as to draw a circular arc in the circumferential direction with a radius Rs centered on the measurement center axis O, and reference points P1 and P2 separated by a center angle θ on the reference line are provided at both end portions. Set to each. Reference points P3 and P4 are set for the reference diameter portion S2 as well as the reference diameter portion S1.

  FIG. 2A shows the measurement line L1 set on the measurement surface S3 along the circumferential direction of the measurement center axis O, and the entire measurement surface S3 is shifted by shifting the measurement line L1 by a predetermined interval in the tire width direction. Can be measured. 2B shows a measurement line L2 set on the measurement surface S3 along the width direction of the tire parallel to the measurement center axis O. The measurement line L2 is shifted by a predetermined interval in the circumferential direction. The entire measurement surface S3 can be measured. In any case, the inner shape of the mold M is measured by measuring the measurement radius, which is the distance from the measurement center axis O set by the reference radius Rs to the measurement point of the measurement line, from the reference diameter portions S1 and S2. Can be measured. Also, the inner surface shape can be measured by setting a preset radius Rc in advance as a radius from the measurement center axis O with respect to the measured surface S3 and measuring a difference from the set radius Rc.

3 to 7 are explanatory diagrams relating to the measurement procedure.
The support frame 2 is fixed to each side end portion of the shaft 1 by screws, and the rotor 30 is fixed to the center portion by screws. For positioning the support frame 2 and the rotor 30 around the shaft shaft 1, marks such as a groove along the central axis T are provided around the shaft shaft 1, and screws are attached so as to match the marks. A support pin 4 (FIG. 1) is attached to a predetermined support hole in advance on the fixed support frame 2. Then, the set screw 41 for fixing the support pin 4 to the support hole is loosened so that the support pin 4 can move in the support hole, and as shown in FIG. 3, the peripheral surface of the shaft shaft 1 and the tip of the support pin 4 A positioning jig 100 such as a caliper is brought into contact therewith. The distance between the two is set by the positioning jig 100 to a value obtained by adding the radius of the shaft shaft 1 to the reference radius Rs, and the set screw 41 for fixing the support pin 4 is tightened so that the support pin 4 does not move. Fix it. Thus, the tip position of the support pin 4 is accurately positioned from the central axis T of the shaft 1 to the reference radius Rs. Similarly, the tip positions of the remaining support pins 4 are positioned from the central axis T to the reference radius Rs.

  Next, as shown in FIG. 4, the origin pin 6 is inserted into the support hole formed at the position where the center line that bisects the center angle of the support frame 2 intersects the arc portion, The positioning jig 100 is brought into contact with the peripheral surface and the tip of the origin pin 6. The distance between the two is set by the positioning jig 100 to a value obtained by adding the radius of the shaft shaft 1 to the set radius Rc, and the set pin 61 for fixing the origin pin 6 is tightened so that the origin pin 6 does not move. Fix it. Thus, the tip position of the origin pin 6 is accurately positioned from the center axis T of the shaft 1 to the set radius Rc.

  Next, as shown in FIG. 5, the rotary arm 3 with the dial gauge 5 fixed to the tip is attached to the rotor 30, and the measurement spindle 5 a of the dial gauge 5 is set in the same direction as the radial direction of the origin pin 6. The position of the rotary arm 3 is adjusted so that Then, the tip of the origin pin 6 is inserted and fixed to the upright support base 201 of the surface plate 200 having a flat upper surface, and the origin pin 6 is set to stand vertically on the upper surface of the surface plate 200. . With the origin pin 6 standing upright, the rotary arm 3 is moved up and down to adjust the position of the dial gauge 5 in the radial direction so that the measuring spindle 5a is in contact with the upper surface of the surface plate 200. Fix to 30. Then, by setting the scale of the dial gauge 5 to the zero point, the scale of the dial gauge 5 is set to the zero point while the tip of the measuring spindle 5a is accurately positioned at the same set radius Rc as the tip of the origin pin 6. Come to instruct. After the zero point setting of the dial gauge 5 is completed, the origin pin 6 is removed from the upright support base 201, and the origin pin 6 is removed from the support frame 2 to complete the preparation of the measurement jig.

  When setting the measurement jig on the mold M, the reference points P1 and P2 are set by setting the tip of the support pin 4 attached to one support frame 2 to the reference diameter portion S1 shown in FIG. The reference points P3 and P4 are set by installing the tip of the support pin 4 attached to the other support frame 2 in the reference diameter portion S2. Therefore, the measurement jig is set so that the center axis T of the shaft 1 corresponds to the measurement center axis O. FIG. 6A shows a state in which the measurement jig is set in the mold M. In this state, the dial gauge 5 attached to the distal end portion of the rotary arm 3 disposed between the support frames 2 is disposed so as to face the measurement surface S3 of the mold M, and the distal end of the measurement spindle 5a of the dial gauge 5 is By contacting the surface to be measured S3, the difference between the set radius Rc set to zero and the measurement radius R is displayed on the measurement scale of the dial gauge 5 and measured (see FIG. 6B). In FIG. 6A, the rotor 30 is rotationally driven to rotate the rotary arm 3 in the circumferential direction of the shaft shaft 1, and the dial gauge 5 is rotated along the circumferential measurement line L1 shown in FIG. . FIG. 6C shows an example of the measurement result. By displaying the difference between the set radius and the measurement radius in a graph, the inner surface shape along the measurement line can be accurately displayed. Moreover, the curvature of the circumferential direction of a to-be-measured surface is obtained by calculating the curvature of an inner surface shape based on the measured measurement radius.

  FIG. 7 is an explanatory diagram of measurement in the tire width direction using the measurement jig set as shown in FIG. In this case, the dial 30 is moved along the measurement line L2 in the width direction shown in FIG. 2 by moving the rotor 30 itself to which the rotary arm 3 is attached along the shaft 1 (see FIG. 7A). (See FIG. 7B). FIG. 7C shows an example of the measurement result. By displaying the difference between the set radius and the measurement radius in a graph, the inner shape of the tire in the width direction can be accurately displayed. Moreover, the curvature of the width direction of a to-be-measured surface is obtained by calculating the curvature of an inner surface shape based on the measured measurement radius.

  In the example described above, the reference radius Rs is set in advance, but the measurement can be performed even when the reference radius Rs is unknown. That is, FIGS. 8 to 12 show the procedure for setting the measuring jig when the reference radius of the mold is unknown. First, as shown in FIG. 8A, the origin pin 6 is attached to the support frame 2 in the same manner as in FIG. 4, and the distance between the peripheral surface of the shaft shaft 1 and the tip of the origin pin 6 is set by the positioning jig 100. The origin pin 6 is fixed by setting to a value obtained by adding the radius of the shaft shaft 1 to Rc. Thus, the tip of the origin pin 6 can be positioned at a distance of the set radius Rc from the central axis of the shaft 1. Next, as shown in FIGS. 9A and 9B, as in FIG. 5, the rotary arm 3 is attached to the roller 30, and the tip of the origin pin 6 is inserted and fixed to the upright support base 201 of the surface plate 200. Set the zero point of gauge 5. Thus, the dial gauge 5 is set to indicate the zero point with the set radius Rc.

  Next, as shown in FIGS. 10A and 10B, the origin pin 6 is removed from the support frame 2 and the support pin 4 is attached instead. The positioning jig 100 is used to place the shaft pin 1 between the peripheral surface of the shaft shaft 1 and the tip of the support pin 4. The support pin 4 is fixed by setting the distance to a provisional reference radius Ra which is provisionally determined and adding the radius of the shaft shaft 1. Thus, the tip of the support pin 4 is positioned at a distance of the temporary reference radius Ra from the center axis of the shaft 1. Next, as shown in FIGS. 11A and 11B, the upright support 300 is installed in each of the reference diameter portions S <b> 1 and S <b> 2 (see FIG. 2) of the mold M, and the support pins 4 are inserted into the positioning holes of the upright support 300. The support pin 4 is set in an upright state. In this state, the measurement is performed by bringing the measuring spindle of the dial gauge 5 into contact with the surface to be measured S3. Then, a difference value Δ which is a difference between the set radius Rc and the measurement radius is measured, and a value obtained by adding the difference value Δ to the temporary reference radius Ra is set as the reference radius Rs. Next, as shown in FIGS. 12A and 12B, with the two support pins 4 attached to the support frame 2, the positioning jig 100 and the peripheral surface of the shaft shaft 1 and the support pins 4 are mounted as in FIG. 3. The support pin 4 is fixed by setting the distance from the tip to a value obtained by adding the radius of the shaft shaft 1 to the reference radius Rs. After setting the reference radius in this way, the measurement operation described above is performed to measure the inner shape of the surface to be measured.

  In this way, after setting the zero point of the dial gauge based on the set radius Rc set for the surface to be measured, the relative positional relationship between the reference diameter portion and the surface to be measured is measured to determine the reference radius. Therefore, accurate measurement can be performed with a simple method even when the reference radius is unknown. Therefore, the inner surface shape can be accurately measured with a simple measuring jig even when the reference diameter portion is not clear as in the “cast-up state” or “intermediate processing state” mold.

  In addition, in the case of a mold in the “casting state” or “intermediate processing state”, the surface to be measured may be cast and deformed. For example, FIG. 13 is a perspective view of an example in which deformation in the width direction of the tire occurs on the measurement target surface S3 of the mold. In FIG. 13A, the surface to be measured S3 is deformed in a convex shape toward the inside, and bulges inward by the difference value X at the center portion. In FIG. 13B, the surface to be measured S3 is deformed in a concave shape toward the outside, and is recessed outward by the difference value Y in the central portion. The difference values X and Y can be measured by moving the dial gauge in the width direction when measuring the difference value Δ shown in FIG. In the case of FIG. 13A, the reference radius Rs = Ra + Δ−X is set, and in the case of FIG. 13B, the reference radius Rs = Ra + Δ + Y is set and the support pin is positioned to perform measurement.

  FIG. 14 is a perspective view of an example in which deformation in the circumferential direction occurs on the measurement target surface S3 of the mold. In FIG. 14A, the surface to be measured S3 is deformed so as to become shallower inward, and is shallower by the difference value X in the central portion. In FIG. 14B, the surface to be measured S3 is deformed so as to become deeper toward the outside, and is deepened by the difference value Y at the central portion. The difference values X and Y can be measured by moving the dial gauge in the circumferential direction when measuring the difference value Δ shown in FIG. Then, in the case of FIG. 14A, the reference radius Rs = Ra + Δ + X is set, and in the case of FIG. 14B, the reference radius Rs = Ra + Δ−Y is set and the support pin is positioned to perform measurement.

  As shown in FIG. 15, when the entire mold is twisted, if the measurement jig is set on the mold after the measurement jig is set, the rattling between the four support pins will occur. Occurs. Therefore, first, a gap (amount of rattling) between the reference diameter portion and the support pin is measured with a gap gauge or the like (in FIG. 15, the gaps A to D are measured). It is necessary to adjust the position of the support pin. Since the cases described with reference to FIGS. 13 to 15 often occur in combination, when performing measurement in an intermediate processing state like a cast product, provisional measurement for position correction of the support pin is performed before measurement, If the main measurement is performed after correcting the position of the support pin based on the measurement result, the inner surface shape of the mold can be accurately measured.

The inner surface shape was measured with the above-described measurement jig using a sectional mold type division mold having nine segment divisions. The mold used was an as-cast state made of aluminum and cast by segment gravity casting using a gypsum mold. FIG. 16 is a dimensional diagram related to the shape of the mold, and the dimensions of each part are as follows.
Length A in the width direction of the tire to be measured A = 215 mm
Length B between the reference diameter part and the outer peripheral surface B = 143 mm
Length of mold tire in width direction C = 290mm
Length D between measured surface and outer peripheral surface D = 100mm
Reference radius R = 317mm
Each of the nine divided molds was measured with five measurement points set in the circumferential direction and five measurement points in the tire width direction. The measurement results are shown in FIGS. In FIG. 17, the measurement data in the circumferential direction of the nine divided molds are arranged in a straight line, and are displayed in a graph in plan with a predetermined interval in the width direction. The surface where the difference from the set radius is 0 is the designed set radius. In FIG. 18, the measurement data in the circumferential direction of the nine divided dies are arranged in a circle and displayed in a graph. The measurement results obtained in this way can be used to determine the dimensional accuracy before machining and to set the position reference when machining the outer peripheral surface of the mold. The final dimensional accuracy of the mold for tire molding It greatly contributed to the improvement.

  The measurement work of the nine divided molds was about 3 hours, and the inner surface shape could be measured easily and accurately even in the as-cast mold. Moreover, although it tried to measure about the same division | segmentation metal mold | die by the prior art described in patent document 1, the positioning and fixation of the mold in an as-cast state were not able to be performed correctly, but the inner surface shape could not be measured. .

  1 .... shaft shaft, 2 .... support frame, 3 .... rotating arm, 4 .... support pin, 5 .... dial gauge, 6 .... origin pin.

Claims (3)

A support pin positioned based on a reference radius along the radial direction from the shaft shaft serving as a measurement center axis is brought into contact with a reference diameter portion set on the inner surface of the tire molding die, and the shaft shaft is supported.
A measuring tool positioned based on a set radius along a radial direction from the shaft shaft is brought into contact with a measurement target surface of the tire molding die, and the measuring tool is axially and / or circumferentially measured with respect to the measurement central axis. A method for measuring the shape of the inner surface of a mold for molding a tire, which is moved to a position to measure the shape of the surface to be measured.   The method for measuring an inner surface shape of a tire molding die according to claim 1, wherein the measuring tool measures a difference between a measurement radius up to a contact point of the surface to be measured and the set radius.   The support pin is positioned based on a temporary reference radius and brought into contact with the reference diameter portion to support the shaft shaft, and the measuring tool positioned based on the set radius is brought into contact with the surface to be measured to make a contact point. 3. The tire molding die according to claim 1, wherein a difference value between the measured radius and the set radius is measured, and the reference radius is set based on the measured difference value and the temporary reference radius. Internal shape measurement method.

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