JP6575229B2 - Method for measuring shape of rubber laminate and method for producing pneumatic tire using the same - Google Patents

Description

  The present invention relates to a method for measuring the shape of a rubber laminate and a method for producing a pneumatic tire using the same.

  Conventionally, in a method for manufacturing a pneumatic tire, a method of forming a rubber laminate such as a tread rubber by winding a belt-like rubber strip spirally around an outer peripheral surface of a forming drum is known.

  Since the cross-sectional profile of the rubber laminate affects the appearance and uniformity of the vulcanized tire, various shape measuring methods have been proposed as methods for measuring the surface shape of the rubber laminate wound around the molding drum. Yes. In the tire manufacturing process, since the rubber laminate wound around the molding drum is in an unvulcanized state with an unstable shape, a non-contact measurement method such as laser light is used for the measurement. Is desirable.

  For example, Patent Document 1 below discloses a technique for measuring the surface shape of a rubber laminate by arranging a plurality of two-dimensional laser displacement meters in the axial direction of a molding drum so as to correspond to a wide tread rubber. Has been.

JP 2007-106090 A

  The laser displacement meter is an optical non-magnetic sensor that obtains distance data from a predetermined reference point to the surface of the rubber laminate by irradiating a measurement object with laser light and photoelectrically converting the reflected light. It is a contact sensor. A laser displacement meter can accurately measure the shape of an object, but it is difficult to be expensive. As a result, the method described in Patent Document 1 requires a plurality of laser displacement meters, and thus has a problem of increasing costs.

  The present invention has been devised in view of the actual situation as described above, and provides a shape measuring method capable of accurately measuring the surface shape of a rubber laminate with an inexpensive configuration and a method for manufacturing a pneumatic tire using the same. The main purpose is to do.

  1st invention of this application is a method for measuring the surface shape of the rubber laminated body which has the 1st width wound around the forming drum, Comprising: The laser which has a 2nd width smaller than the said 1st width A first measurement step of irradiating the rubber laminate with light to acquire distance data from a predetermined reference point to the surface of the rubber laminate, and the rubber laminate that could not be measured in the first measurement step Moving the molding drum in the axial direction so that the remaining area of the rubber laminate faces the laser beam, and irradiating the remaining area of the rubber laminate with the laser beam, and the reference point And a second measurement step of acquiring distance data from the rubber laminate to the surface of the rubber laminate.

  In the shape measuring method according to the present invention, in the first measuring step and the second measuring step, the distance data is preferably measured within a plane including a rotation axis of the forming drum.

  In the shape measuring method according to the present invention, it is desirable that the first measuring step and the second measuring step measure the distance data at 4 to 12 locations in the circumferential direction of the rubber laminate.

  In the shape measuring method according to the present invention, the rubber laminate preferably includes a tread rubber of a pneumatic tire.

  2nd invention of this application is a manufacturing method of a pneumatic tire, Comprising: Based on the cross-sectional profile of the rubber laminated body obtained by the shape measuring method of the said rubber laminated body, the quality of the molding of the said rubber laminated body is judged. Including a process.

  The shape measuring method of the first invention includes a first measuring step of irradiating the rubber laminate with laser light to obtain distance data from a predetermined reference point to the surface of the rubber laminate, and the remaining rubber laminate. A second measurement step of irradiating the region with laser light and acquiring distance data from the reference point to the surface of the rubber laminate. Furthermore, a moving step of moving the forming drum in the axial direction to irradiate the remaining area with laser light is included. Thereby, the said remaining area | region which was not able to be measured in the 1st measurement process can be made to oppose a laser beam, and a surface shape can be measured over the whole area | region of a rubber laminated body, without using several expensive laser displacement meters. .

  The manufacturing method of the second invention includes a step of judging the quality of the rubber laminate based on the cross-sectional profile of the rubber laminate obtained by the method for measuring the shape of the rubber laminate. It is possible to suppress the appearance failure of the sulfurized tire and the deterioration of uniformity.

It is a side view which shows schematic structure of the shape measuring apparatus for enforcing the shape measuring method which is one Embodiment of this invention. It is a flowchart which shows the procedure of this shape measuring method. It is sectional drawing of the shape measuring apparatus of FIG. It is the graph which plotted the distance data measured by the shape measuring method of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a shape measuring apparatus 1 for carrying out a shape measuring method according to an embodiment of the present invention.

  The shape measuring apparatus 1 moves the cylindrical forming drum 2, the rotating shaft 3 of the forming drum 2, the laser displacement meter 4 for measuring the surface shape of the rubber laminate 10, and the rotating shaft 3 in the direction of the axis 3A. Moving means 5 and the like. The shape measuring apparatus 1 is included in a part of a pneumatic tire molding apparatus, for example. When a green tire is formed, if a mechanism for moving the forming drum 2 in the direction of the axis 3 </ b> A already exists, this mechanism can be used as the moving means 5.

  A rubber laminate 10 is wound around the outer peripheral surface of the molding drum 2. In the present embodiment, the rubber laminate 10 constitutes a tread rubber of a pneumatic tire, for example. That is, the shape measuring device 1 measures the surface shape of the tread rubber wound around the forming drum 2. The rubber laminate 10 to be measured is not limited to the tread rubber, and may be, for example, a sidewall rubber or an inner runner rubber.

  The rotating shaft 3 supports the forming drum 2 to be rotatable. As the molding drum 2 rotates, the rubber laminate 10 is wound around the outer peripheral surface of the molding drum 2 to form tread rubber. The rubber laminate 10 may have a form in which a rubber strip constituting the base layer and a rubber strip constituting the cap layer are wound separately.

  The laser displacement meter 4 irradiates the surface of the rubber laminate 10 as a measurement object with the laser light L1 and photoelectrically converts the reflected light L2 from the predetermined reference point to the surface of the rubber laminate 10. It is an optical non-contact sensor that acquires the distance data. The laser displacement meter 4 of the present embodiment is fixed to the installation surface 20 of the shape measuring device 1.

  The moving means 5 supports the rotating shaft 3 and moves the forming drum 2 and the rotating shaft 3 in the direction of the axis 3A. For this reason, the moving means 5 is configured to be movable in the direction of the axis 3 </ b> A of the rotary shaft 3 with respect to the installation surface 20. For example, the moving means 5 is mounted on a slide unit 6 that can move on a rail 21 that is laid in parallel on the installation surface 20 along the axis 3 </ b> A of the rotary shaft 3.

  FIG. 2 is a flowchart showing the procedure of the shape measuring method of the present invention. The shape measuring method includes a first measuring step S1, a moving step S2, and a second measuring step S3.

  In the first measurement step S1, the rubber laminate 10 is irradiated with the laser beam L1, and distance data from a predetermined reference point to the surface 10A of the rubber laminate 10 is acquired. The reference point is an origin for distance measurement defined in the laser displacement meter 4, for example, a position of a laser light source provided in the laser displacement meter 4.

  FIG. 3 shows how the surface shape of the rubber laminate 10 is measured in the first measurement step S1. In the present embodiment, the belt reinforcing layer 11 and the jointless band reinforcing layer 12 are sequentially wound around the outer peripheral surface of the forming drum 2, and the rubber laminate 10 is wound around the radially outer side thereof.

  The rubber laminate 10 can be formed, for example, by winding a belt-shaped rubber strip 10B in a spiral shape. The width of the rubber laminate 10 is the first width W1, for example, 200 mm or more. On the other hand, the irradiation width of the laser light L1 varies depending on the specifications of the laser displacement meter 4, and the laser displacement meter 4 capable of measuring the distance with a large irradiation width (measurement region) with high accuracy is generally expensive. Therefore, in this embodiment, the laser displacement meter 4 that irradiates the laser beam L1 whose measurement region is the second width W2 smaller than the first width W1 is applied. Thereby, the cost reduction of the shape measuring apparatus 1 can be aimed at.

  As already described, the second width W <b> 2 that is the measurement region of the laser displacement meter 4 is smaller than the first width W <b> 1 that is the width of the rubber laminate 10. For this reason, the remaining area | region R of the rubber laminated body 10 which was not able to be measured in 1st measurement process S1 arises.

  Thereafter, in the moving step S2, the forming drum 2 is moved in the axial direction 3X so that the remaining region R faces the laser beam L1. Thereby, it is possible to irradiate the laser beam L1 over the entire region of the rubber laminate 10 in the axial direction 3X.

  In the second measurement step S3, the remaining region R of the rubber laminate 10 is irradiated with the laser light L1, and distance data from the reference point to the surface 10A of the rubber laminate 10 is acquired. Through the first measurement step S1 and the second measurement step S3, the shape of the surface 10A can be measured over the entire region in the axial direction 3X of the rubber laminate 10.

  FIG. 4 is a graph plotting the distance data measured in the first measurement step S1 and the second measurement step S3. In FIG. 4, the horizontal axis represents the distance in the axial direction 3X (the width of the rubber laminate 10), and the vertical axis represents the radial distance (the thickness of the rubber laminate 10).

  The movement process S2 and the second measurement process S3 may be performed simultaneously. In this case, distance data of the remaining region R of the rubber laminate 10 is acquired in the second measurement step S3 while the molding drum 2 is moved in the axial direction 3X in the movement step S2. Therefore, it is possible to measure the shape of the surface 10A of the rubber laminate 10 in a short time.

  In the first measurement step S1 and the second measurement step S3, it is desirable that the rotation of the molding drum 2 is stopped and the laser beam L1 is irradiated in a plane including the axis 3A of the rotation shaft 3 of the molding drum 2. . Thereby, the distance data from the reference point to the surface 10A of the rubber laminate 10 can be acquired in the plane including the axis 3A. Thereby, the cross-sectional profile along the axial center 3A of the rubber laminate 10 can be accurately measured in a short time.

  According to this shape measuring method, the remaining region R that could not be measured in the first measuring step S1 can be made to face the laser beam L1, and the rubber laminate 10 can be used without using a plurality of expensive laser displacement meters 4. The surface shape can be measured over the entire area.

  It is also possible to acquire distance data by irradiating the remaining region R with the laser light L1 by moving the laser displacement meter 4 in the axial direction 3X. However, in this case, as the laser displacement meter 4 moves, the laser displacement meter 4 may vibrate and affect the distance data. In the present embodiment, since the molding drum 2 is moved in the axial direction 3X and the laser displacement meter 4 is fixed to the installation surface 20, the laser light L1 is moved relative to the rubber laminate 10. The vibration of the laser displacement meter 4 can be suppressed. Thereby, it becomes possible to further improve the measurement accuracy of the surface shape.

  In the present embodiment, the molding drum 2 is configured to be rotatable around the rotation shaft 3 in order to easily wrap the rubber laminate 10 around the outer peripheral surface of the molding drum 2. Therefore, by rotating the molding drum 2 around which the rubber laminate 10 is wound by a predetermined angle and repeating the first measurement step S1 to the second measurement step S3, at a plurality of locations in the circumferential direction of the rubber laminate 10, Distance data can be measured. By measuring the distance data of a plurality of locations, it is possible to calculate the average value and standard deviation, and to statistically determine whether the rubber laminate 10 is molded.

  As for the measurement location of the circumferential direction of the rubber laminated body 10, 4-12 locations are desirable. When the number of measurement locations is less than 4, the average value of the measurement values is likely to vary due to the level difference between the adjacent rubber strips 10B, and it may be difficult to accurately determine whether the rubber laminate 10 is molded. On the other hand, when the number of measurement points exceeds 12, the time required for shape measurement becomes long and the productivity is lowered.

  In the manufacturing method of a pneumatic tire including this shape measuring method, the quality of the rubber laminate 10 is determined based on the cross-sectional profile of the rubber laminate 10 measured as described above, and only good products are transferred to the downstream process. Can be made. That is, the method for manufacturing a pneumatic tire according to the present invention includes a determination step of determining whether or not the rubber laminate 10 is molded based on the cross-sectional profile of the rubber laminate 10. In this determination step, it is possible to determine whether the rubber laminate 10 is molded or not by comparing the measured cross-sectional profile of the rubber laminate 10 with a target cross-sectional profile. The rubber laminate 10 in which molding failure has occurred can be transferred only to non-defective products to the next step by performing an operation such as peeling the rubber strip 10B from the molding drum 2 or the like and winding it again. According to such a method for manufacturing a pneumatic tire, it is possible to suppress vulcanization or the like of a raw tire in which a molding failure has occurred, and to improve productivity, and to suppress deterioration in appearance and uniformity of the vulcanized tire. sell.

  As mentioned above, although embodiment of this invention was described in detail, this invention is changed and implemented in various aspects, without being limited to said specific embodiment.

   100 pneumatic tires of size 235 / 45R18 were manufactured for each example according to the specifications in Table 1 and produced by the pneumatic tire manufacturing method including the shape measuring method shown in FIGS. , Appearance performance and uniformity performance were evaluated. As a result of measuring the surface shape of the tread portion, the rubber strip was peeled off from the molding drum or the like when the average value of the cross-sectional profile was more than the reference value (0.6 mm) from the target cross-sectional profile. Then, another rubber strip was wound again, so that only non-defective products satisfying the reference value were transferred to the next step. The test method is as follows.

<Productivity>
For each case, the time required to form the green tire was measured. A result is represented by the index | exponent which makes Example 1 100, and shows that the productivity of a green tire is excellent, so that a numerical value is small.

<Appearance performance>
The appearance of the tread portion of the vulcanized tire was visually confirmed, and the bear occurrence rate was calculated. A result is represented by the index | exponent which makes Example 1 100, and shows that external appearance performance is excellent, so that a numerical value is small.

<Uniformity performance>
The RFV of the vulcanized tire was measured and the standard deviation of its primary component was calculated. The smaller the value, the better the uniformity performance.

  As is apparent from Table 1, it was confirmed that the shape measurement method of the example significantly improved the appearance performance and uniformity performance without hindering the productivity as compared with the comparative example.

2 Molding drum 10 Rubber laminate 10A Surface L1 Laser light S1 First measurement step S2 Moving step S3 Second measurement step

Claims (5)

A method for measuring a surface shape of a rubber laminate having a first width wound around a molding drum,
The rubber laminate is irradiated with laser light having a second width smaller than the first width within a plane along the axial direction of the molding drum, and the rubber laminate is irradiated from a predetermined reference point. A first measurement step for obtaining distance data to the surface;
A moving step of moving the molding drum in the axial direction so that the remaining region of the rubber laminate that could not be measured in the first measuring step faces the laser beam;
A second measurement step of irradiating the remaining region of the rubber laminate with the laser beam to obtain distance data from the reference point to the surface of the rubber laminate. Body shape measurement method.   The method for measuring a shape of a rubber laminate according to claim 1, wherein in the first measurement step and the second measurement step, the distance data is measured within a plane including a rotation axis of the molding drum.   The shape measurement method for a rubber laminate according to claim 1 or 2, wherein the first measurement step and the second measurement step measure the distance data at 4 to 12 locations in the circumferential direction of the rubber laminate. 4. The method of measuring a shape of a rubber laminate according to claim 1, wherein the rubber laminate is formed by winding a belt-like rubber strip spirally while shifting in the axial direction of the molding drum. 5. . A pneumatic tire manufacturing method comprising:
A pneumatic tire comprising a step of judging whether or not the rubber laminate is molded based on a cross-sectional profile of the rubber laminate obtained by the method for measuring a shape of a rubber laminate according to claim 4. Manufacturing method.

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