JP2020197487A - Method for measuring thickness of bet-like rubber member - Google Patents

Abstract

To provide a method for measuring the thickness of a belt-like rubber member 2 capable of contributing to improvement in productivity of a tire.SOLUTION: This method for measuring the thickness includes the steps of: (1) immersing at least one plane 8 out of two planes 8 of a belt-like rubber member 2 into liquid 12 put in a liquid tank 10; (2) transmitting, in the liquid 12, an ultrasonic wave toward one plane 8 of the belt-like rubber member 2 immersed in the liquid 12 and receiving the reflected wave of the ultrasonic wave; and (3) calculating the thickness of each of sheets 6 constituting the belt-like rubber member 2 based on the propagation time from the transmission of the ultrasonic wave until the reception of the reflected wave, and the propagation speed of the ultrasonic wave.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for measuring the thickness of a strip-shaped rubber member.

For example, a tire tread has a cap layer that includes a tread surface and a base layer that is located radially inside the cap layer and covers the belt. Since the cap layer comes into contact with the road surface, a rubber composition in consideration of grip force is used for this cap layer. For the base layer, a rubber composition in which heat generation is suppressed is used in consideration of the influence on rolling resistance.

In the manufacture of tires, the rubber composition for the base layer and the rubber composition for the cap layer are simultaneously extruded in the extruder, so that the sheet for the base layer is laminated with the sheet for the cap layer. In addition, a strip-shaped rubber member is prepared.

A method of forming a strip-shaped rubber member by extruding a plurality of rubber compositions at the same time is disclosed in, for example, Patent Document 1 below.

Japanese Unexamined Patent Publication No. 2016-7721

The strip-shaped rubber member includes a plurality of laminated sheets. In the molding of the strip-shaped rubber member, the thickness of each sheet is confirmed in order to produce a high quality tire. In checking the thickness of this sheet, for example, a strip-shaped rubber member is cut to prepare a cross section of the strip-shaped rubber member. The thickness of each sheet is measured by the operator visually observing this cross section using a magnifying glass.

In the above-mentioned conventional measurement method, the band-shaped rubber member used for checking the thickness is not used for the tire part. Depending on the cutting position, there is a concern that scraping may occur. In the thickness measuring method involving cutting of the strip-shaped rubber member, loss of the strip-shaped rubber member occurs. The loss of the band-shaped rubber member hinders the improvement of tire productivity.

According to the measuring device using X-rays, it is possible to grasp the thickness of the sheet without cutting the strip-shaped rubber member. However, measuring devices using X-rays are expensive, and care must be taken when handling X-rays.

From the viewpoint of improving tire productivity, it is required to establish a technique for measuring the thickness of the strip-shaped rubber member, which is safe and does not involve loss of the strip-shaped rubber member.

The present invention has been made in view of such an actual situation, and an object of the present invention is to provide a method for measuring the thickness of a strip-shaped rubber member, which can contribute to the improvement of tire productivity.

The method for measuring the thickness of a strip-shaped rubber member according to one aspect of the present invention is a method for measuring the thickness of a strip-shaped rubber member obtained by laminating a sheet made of a plurality of unvulcanized rubbers in the thickness direction. hand,
(1) A step of immersing at least one of the two flat surfaces of the strip-shaped rubber member in the liquid contained in the liquid tank.
(2) A step of transmitting ultrasonic waves toward one plane of the strip-shaped rubber member immersed in the liquid in the liquid and receiving the reflected waves, and (3) transmitting the ultrasonic waves. The step of calculating the thickness of each sheet constituting the strip-shaped rubber member is included based on the propagation time from the time of receiving the reflected wave to the reception of the reflected wave and the propagation velocity of the ultrasonic wave.

Preferably, in the method for measuring the thickness of the strip-shaped rubber member, the strip-shaped rubber member is in a conveyed state.

Preferably, in this method of measuring the thickness of the strip-shaped rubber member, the plurality of sheets constituting the strip-shaped rubber member have different specific gravities.

According to the method for measuring the thickness of the strip-shaped rubber member of the present invention, the thickness of each sheet constituting the strip-shaped rubber member can be measured safely and without loss of the strip-shaped rubber member. This method of measuring the thickness of the strip-shaped rubber member can contribute to the improvement of tire productivity.

FIG. 1 is a schematic view showing a measuring device used in the method for measuring the thickness of a strip-shaped rubber member according to an embodiment of the present invention. FIG. 2 is an explanatory diagram illustrating the measurement of the thickness by the measuring device. FIG. 3 is a schematic view showing another measuring device.

Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the drawings as appropriate.

FIG. 1 schematically shows an example of a measuring device 4 used in the method for measuring the thickness of a strip-shaped rubber member 2 according to an embodiment of the present invention. The measuring device 4 is a device that measures the thickness of the strip-shaped rubber member 2.

The band-shaped rubber member 2 includes a plurality of sheets 6 laminated in the thickness direction thereof. Each sheet 6 is made of unvulcanized rubber. Although not described in detail, the strip-shaped rubber member 2 can be obtained, for example, by simultaneously extruding a plurality of unvulcanized rubbers with an extruder. The band-shaped rubber member 2 may be formed by preparing a plurality of sheets 6 and laminating these sheets 6.

The unvulcanized rubber is a rubber composition in an unvulcanized state. The unvulcanized rubber is obtained by mixing the base rubber and chemicals using a kneader such as a Banbury mixer. The base rubber includes natural rubber (NR), butadiene rubber (BR), styrene butadiene rubber (SBR), isoprene rubber (IR), ethylene propylene rubber (EPDM), chloroprene rubber (CR), and acrylonitrile butadiene rubber (NBR). ) And butyl rubber (IIR) are exemplified. Chemicals include reinforcing agents such as carbon black and silica, plasticizers such as aromatic oils, fillers such as zinc oxide, lubricants such as stearic acid, antiaging agents, processing aids, sulfur and A vulcanization accelerator is exemplified. The selection of the base rubber and the chemicals, the content of the selected chemicals, etc. are appropriately determined according to the specifications of the components to which this rubber is applied.

In this strip-shaped rubber member 2, the composition of the unvulcanized rubber constituting one sheet 6 is different from the composition of the unvulcanized rubber constituting the other sheet 6 laminated on the one sheet 6. The plurality of sheets 6 constituting the strip-shaped rubber member 2 have different compositions from each other.

For example, if the composition of the two unvulcanized rubbers is different, the specific gravity of the vulcanized rubber obtained by vulcanizing the unvulcanized rubber is generally different. Here, the specific gravity is measured in accordance with JIS K6268 (vulcanized rubber-density measurement) using a rubber piece made of vulcanized rubber obtained by vulcanizing unvulcanized rubber.

In this measuring method, the difference in the composition of the unvulcanized rubber is represented by the specific gravity of the vulcanized rubber obtained by vulcanizing the unvulcanized rubber. That is, the specific gravity of the vulcanized rubber obtained by vulcanizing the unvulcanized rubber for one sheet 6 is the specific gravity of the vulcanized rubber obtained by vulcanizing the unvulcanized rubber for the other sheet 6. If it is different from, it is judged that the composition of the unvulcanized rubber for one sheet 6 and the composition of the unvulcanized rubber for the other sheet 6 are different.

As described above, the plurality of sheets 6 constituting the strip-shaped rubber member 2 have different compositions from each other. Therefore, the plurality of sheets 6 constituting the band-shaped rubber member 2 have different specific gravities from each other.

The band-shaped rubber member 2 shown in FIG. 1 is a tread component. The band-shaped rubber member 2 includes two sheets 6 laminated in the thickness direction. One sheet 6a is made of unvulcanized rubber for the cap layer in contact with the road surface. The other sheet 6b consists of unvulcanized rubber for the base layer located inside the cap layer.

The band-shaped rubber member 2 has two flat surfaces 8. These planes 8 extend in the width direction and the length direction of the band-shaped rubber member 2. In the band-shaped rubber member 2, one flat surface 8a (hereinafter, also referred to as a first flat surface 8a) is a sheet 6a made of unvulcanized rubber for the cap layer (hereinafter, also referred to as a cap sheet 6a). ). The other plane 8b (hereinafter, also referred to as a second plane 8b) is composed of a sheet 6b (hereinafter, also referred to as a base sheet 6b) made of unvulcanized rubber for the base layer.

In the tread, the composition of the base layer and the composition of the cap layer are different. Specifically, the specific gravity of the base layer is smaller than the specific gravity of the cap layer. Specifically, the ratio of the difference between the specific gravity of the cap layer and the specific gravity of the base layer to the specific gravity of the cap layer is in the range of 5% or more and 15% or less. The specific gravity of the base layer is in the range of 1.05 or more and 1.15 or less, and the specific gravity of the cap layer is in the range of 1.15 or more and 1.25 or less.

Although not described in detail, in the manufacture of tires, the strip-shaped rubber member 2 is formed by simultaneously extruding the unvulcanized rubber for the cap layer and the unvulcanized rubber for the base layer in an extruder (not shown). can get. By cutting the strip-shaped rubber member 2 to a predetermined length using a cutting machine (not shown), tread rubber as a tread component can be obtained. By combining the tread rubber with other parts, an unvulcanized tire, that is, a raw tire can be obtained. The raw tire is pressurized and heated to obtain a tire.

The measuring device 4 shown in FIG. 1 constitutes a part of the tread rubber production line. The band-shaped rubber member 2 is transferred to the measuring device 4 from the right side of the paper surface. The band-shaped rubber member 2 is transferred from the measuring device 4 to the left side of the paper surface. In FIG. 1, the right side of the paper is the upstream side of the production line, and the left side is the downstream side of the production line.

Although not shown, the measuring device 4 is located on the downstream side of the extruder that forms the band-shaped rubber member 2. The measuring device 4 is located on the upstream side of the cutting machine that cuts the strip-shaped rubber member 2 to form the tread rubber.

The measuring device 4 includes a liquid tank 10, a liquid 12, and an ultrasonic sensor 14. The liquid tank 10 is filled with the liquid 12. Water is preferably used as the liquid 12.

In this measuring device 4, the strip-shaped rubber member 2 is set so that the back surface side thereof comes into contact with the liquid 12 stretched in the liquid tank 10. The band-shaped rubber member 2 is set in the measuring device 4 shown in FIG. 1 with the second plane 8b on the back side. Therefore, in this measuring device 4, the base sheet 6b forming the second plane 8b comes into contact with the liquid 12. When the strip-shaped rubber member 2 is set on the measuring device 4 with the first plane 8a on the back side, the cap sheet 6a forming the first plane 8a comes into contact with the liquid 12.

In this measuring device 4, the band-shaped rubber member 2 is supported by a pair of holding rollers 16. As a result, in the measuring device 4, the contact state of the band-shaped rubber member 2 with the liquid 12 is maintained. The measuring device 4 includes a pair of holding rollers 16 that maintain the contact state of the band-shaped rubber member 2 with the liquid 12.

The pair of holding rollers 16 extend in the width direction of the band-shaped rubber member 2. These holding rollers 16 are arranged at intervals in the length direction of the strip-shaped rubber member 2. Each holding roller 16 is rotatably supported by the liquid tank 10 by a supporting means (for example, a bearing) (not shown). In FIG. 1, the symbol AL is the axis of the holding roller 16. In the liquid tank 10, the holding roller 16 can rotate about the axis AL.

In this measuring device 4, a commercially available ultrasonic sensor is used as the ultrasonic sensor 14. The ultrasonic sensor 14 includes a probe 18 and a controller 20. The probe 18 and the controller 20 are connected by a communication cable 22. The probe 18 is set in the liquid 12 stretched in the liquid tank 10. The controller 20 is arranged at an arbitrary position outside the liquid tank 10.

The probe 18 is arranged between the holding roller 16 on the upstream side and the holding roller 16 on the downstream side at a position facing the back surface of the band-shaped rubber member 2. The probe 18 includes a piezoelectric element 24. The piezoelectric element 24 emits ultrasonic waves toward the back surface of the band-shaped rubber member 2 and receives the reflected waves. That is, the probe 18 includes a transmitting unit 26 that emits ultrasonic waves and a receiving unit 28 that receives reflected waves.

The controller 20 is composed of, for example, a microcomputer having a calculation unit such as a CPU, a storage unit including a RAM and a ROM, and the like. The controller 20 exerts a predetermined function when the arithmetic unit executes the program stored in the storage unit.

FIG. 2 schematically shows a situation in which ultrasonic waves transmitted toward the band-shaped rubber member 2 propagate in the band-shaped rubber member 2. In FIG. 2, the double-headed arrow T1 represents the distance from the probe 18 to the boundary 30 between the liquid 12 and the base sheet 6b (hereinafter, also referred to as the first boundary 30a). The double-headed arrow T2 represents the distance from the probe 18 to the boundary 30 between the base sheet 6b and the cap sheet 6a (hereinafter, also referred to as the second boundary 30b). The double-headed arrow T3 represents the distance from the probe 18 to the boundary 30 (hereinafter, also referred to as the third boundary 30c) between the cap sheet 6a and the atmosphere 32 located outside the cap sheet 6a. The double-headed arrow TB is the thickness of the base sheet 6b. This thickness TB is represented by the difference between the distance T2 and the distance T1. The double-headed arrow TC is the thickness of the cap sheet 6a. This thickness TC is represented by the difference between the distance T3 and the distance T2.

In this measuring device 4, there is a difference in specific gravity between water as the liquid 12 and the base sheet 6b. There is also a difference in specific gravity between the base sheet 6b and the cap sheet 6a. There is also a difference in specific gravity between the cap sheet 6a and the air as the atmosphere 32. Therefore, reflection of ultrasonic waves transmitted from the probe 18 occurs at the first boundary 30a, the second boundary 30b, and the third boundary 30c.

The controller 20 of the ultrasonic sensor 14 has a function of instructing the probe 18 to transmit ultrasonic waves at a predetermined propagation speed. In this measuring device 4, when the controller 20 instructs the probe 18 to transmit ultrasonic waves, the probe 18, that is, the transmitting portion 26 transmits ultrasonic waves toward the band-shaped rubber member 2 at a predetermined propagation speed. The probe 18, that is, the receiving unit 28 receives the reflected wave, and the reception information of the reflected wave is input to the controller 20.

The controller 20 has a function of measuring the time from when the probe 18 emits an ultrasonic wave to when it receives a reflected wave (hereinafter, also referred to as a propagation time). In this measuring device 4, the controller 20 takes time for the ultrasonic wave to reciprocate between the probe 18 and the first boundary 30a based on the ultrasonic wave transmission time and the reflected wave reception time, that is, the first. Calculate the propagation time. The controller 20 further calculates the time required for the ultrasonic waves to reciprocate between the probe 18 and the second boundary 30b, that is, the second propagation time. Then, the controller 20 calculates the time required for the ultrasonic wave to reciprocate between the probe 18 and the third boundary 30c, that is, the third propagation time.

The controller 20 has a function of analyzing the thickness of the strip-shaped rubber member 2 based on the propagation speed and the propagation time. In the measuring device 4, the controller 20 calculates the distance T1 from the probe 18 to the first boundary 30a by using the first propagation time and the propagation speed of the ultrasonic wave. The distance T2 from the probe 18 to the second boundary 30b is calculated using the second propagation time and the propagation velocity. By subtracting the distance T1 from the distance T2, the thickness TB of the base sheet 6b is calculated. The distance T3 from the probe 18 to the third boundary 30c is calculated using the third propagation time and the propagation velocity. By subtracting the distance T2 from the distance T3, the thickness TC of the cap sheet 6a is calculated.

Next, a method for measuring the strip-shaped rubber member 2 using the measuring device 4 described above will be described. This measuring method is a method for measuring the thickness of the strip-shaped rubber member 2 obtained by laminating a sheet 6 made of a plurality of unvulcanized rubbers in the thickness direction.

This measuring method includes a step of immersing at least one of the two flat surfaces 8 of the band-shaped rubber member 2 in the liquid 12 contained in the liquid tank 10 (hereinafter, also referred to as a setting step).

In this measuring method, the strip-shaped rubber member 2 is transferred to the measuring device 4 by a transfer means (not shown). In the setting step, the strip-shaped rubber member 2 is set in the measuring device 4 so that the second plane 8b is immersed in the liquid 12 (here, water) put in the liquid tank 10.

This measuring method is a step of transmitting ultrasonic waves toward one flat surface 8 of the band-shaped rubber member 2 immersed in the liquid 12 in the liquid 12 and receiving the reflected waves (hereinafter, also referred to as a measuring step). ) Is included.

In this measuring method, when the strip-shaped rubber member 2 is set in the measuring device 4, the measuring step is started. In this measurement step, in the liquid 12, the probe 18 arranged so as to face the band-shaped rubber member 2 is directed toward the second plane 8b of the band-shaped rubber member 2 immersed in the liquid 12 at a predetermined propagation speed. Ultrasonic waves are transmitted. As described above, in this measuring device 4, the reflection of the ultrasonic wave transmitted from the probe 18 occurs at the first boundary 30a, the second boundary 30b, and the third boundary 30c. Therefore, the ultrasonic waves reflected at the first boundary 30a, the ultrasonic waves reflected at the second boundary 30b, and the ultrasonic waves reflected at the third boundary 30c are received by the probe 18 as reflected waves.

In the measurement step, ultrasonic waves are transmitted toward the second plane 8b of the band-shaped rubber member 2 immersed in the liquid 12 in the liquid 12, and the reflected waves are received. As a result, the propagation time of ultrasonic waves is measured in the controller 20. Specifically, the first propagation time required for the ultrasonic wave to reciprocate between the probe 18 and the first boundary 30a, and the ultrasonic wave reciprocating between the probe 18 and the second boundary 30b. The second propagation time and the third propagation time required for the ultrasonic wave to reciprocate between the probe 18 and the third boundary 30c are measured.

In this measuring method, the thickness of each sheet 6 constituting the band-shaped rubber member 2 is calculated based on the propagation time from the transmission of the ultrasonic wave to the reception of the reflected wave and the propagation speed of the ultrasonic wave. Including a step (hereinafter, also referred to as an analysis step).

In this measurement method, when the first propagation time, the second propagation time, and the third propagation time are measured, the analysis step is started. In this analysis step, the distance T1 from the probe 18 to the first boundary 30a and the probe 18 in the controller 20 are determined by the measured first propagation time, second propagation time and third propagation time, and the propagation speed of ultrasonic waves. The distance T2 from to the second boundary 30b and the distance T3 from the probe 18 to the third boundary 30c are calculated. Further, from the distance T1, the distance T2, and the distance T3, the thickness TB of the base sheet 6b and the thickness TC of the cap sheet 6a are calculated.

In this measuring method, ultrasonic waves are transmitted in the liquid 12 toward the flat surface 8 of the band-shaped rubber member 2 immersed in the liquid 12. Since the attenuation of ultrasonic waves is suppressed, the reflected wave is received clearly. In this measuring method, the thickness of a plurality of sheets 6 laminated in the thickness direction can be measured safely and non-contactly. Since it is not necessary to cut the strip-shaped rubber member 2 to prepare a cross section of the strip-shaped rubber member 2 in order to grasp the thickness of each sheet 6, this measuring method does not involve loss of the strip-shaped rubber member 2. Since almost all of the manufactured strip-shaped rubber members 2 can be used as parts, this measurement method can contribute to the improvement of tire productivity.

As described above, the extruder is located on the upstream side of the measuring device 4, and the cutting machine is located on the downstream side. Although not shown, in the tread rubber production line, the section between the extruder and the cutting machine is composed of a transport line for transporting the strip-shaped rubber member 2. As a result, the tread rubber is continuously manufactured by cutting the strip-shaped rubber member 2 with the cutting machine while manufacturing the strip-shaped rubber member 2 with the extruder.

In this measuring method, the measuring device 4 constitutes a part of the transport line. Therefore, the strip-shaped rubber member 2 manufactured in the extruder passes through the measuring device 4. In this measuring method, the thickness of each sheet 6 is measured for the strip-shaped rubber member 2 passing through the measuring device 4, that is, the strip-shaped rubber member 2 in the conveyed state. In this measuring method, the thickness of each sheet 6 can be grasped over the entire length of the strip-shaped rubber member 2. This measuring method can contribute to the production of high quality tires. Since the formation of the strip-shaped rubber member 2 in which the thickness of the sheet 6 is disturbed is effectively prevented, the occurrence of loss of the strip-shaped rubber member 2 is also suppressed. This measuring method can further contribute to the improvement of tire productivity. From this point of view, in this measuring method, the band-shaped rubber member 2 is preferably in a conveyed state.

In this measuring method, the difference in specific gravity between one sheet 6 constituting the band-shaped rubber member 2 and the other sheet 6 laminated on the one sheet 6 contributes to the reflection of ultrasonic waves. From the viewpoint of accurately grasping the thickness of each sheet 6, when the specific gravity of one sheet 6 is smaller than the specific gravity of the other sheet 6, the specific gravity of the other sheet 6 is equal to that of the other sheet 6. The specific gravity difference, which is represented by the ratio of the difference from the specific gravity of the sheet 6, is preferably 5% or more, more preferably 7% or more, still more preferably 10% or more. From the viewpoint of accurately grasping the thickness of each sheet 6, the larger the specific gravity difference is, the more preferable it is. Therefore, the upper limit of the specific gravity difference is not set.

As described above, in this measuring method, the thickness of each sheet 6 is grasped by transmitting ultrasonic waves from the probe 18 toward the band-shaped rubber member 2. From the viewpoint of accurately grasping the thickness of each sheet 6, the frequency of the ultrasonic wave transmitted from the probe 18 is preferably 1.5 MHz or more, and preferably 5.0 MHz or less. The frequency of this ultrasonic wave is more preferably 2.0 MHz or more, and more preferably 4.0 MHz or less.

In the measuring device 4 used in this measuring method, the piezoelectric element 24 included in the probe 18 has a disk shape. In this measuring method, the outer diameter of the piezoelectric element 24 is preferably 3.0 mm or more, and preferably 10.0 mm or less, from the viewpoint of accurately grasping the thickness of each sheet 6. The outer diameter is more preferably 4.0 mm or more, and more preferably 8.0 mm or less.

In the measuring device 4 used in this measuring method, the temperature of the liquid 12 filled in the liquid tank 10 is preferably 30 ° C. or lower. As a result, cooling of the band-shaped rubber member 2 is promoted. In this measuring method, since the thickness of each sheet 6 is measured in a stable shape, the thickness of each sheet 6 can be accurately grasped.

FIG. 3 schematically shows an example of a measuring device 42 used in the method for measuring the thickness of the strip-shaped rubber member 2 according to another embodiment of the present invention. The measuring device 42 also constitutes a part of the tread rubber manufacturing line, like the measuring device 4 shown in FIG. In FIG. 3, the right side of the paper is the upstream side of the production line, and the left side is the downstream side of the production line. The band-shaped rubber member 2 is manufactured by an extruder (not shown) located on the upstream side of the measuring device 42, and is transferred to the measuring device 42. The band-shaped rubber member 2 is transferred from the measuring device 42 to a cutting machine (not shown) located on the downstream side of the measuring device 42.

The measuring device 42 includes a liquid tank 44, a liquid 46, a pair of holding rollers 48, and an ultrasonic sensor 50. The measuring device 42 has the same configuration as the measuring device 4 shown in FIG. 1 except for the pair of holding rollers 48. The same elements as the elements of the liquid tank 10, the liquid 12, and the ultrasonic sensor 14 shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

In this measuring device 42, the pair of holding rollers 48 extend in the width direction of the band-shaped rubber member 2. These holding rollers 48 are arranged at intervals in the length direction of the strip-shaped rubber member 2. Each holding roller 48 is rotatably supported in the liquid tank 44 by a supporting means (eg, bearing) (not shown). In FIG. 3, reference numeral AL is the axis of the holding roller 48. In the liquid tank 44, the holding roller 48 can rotate about the axis AL.

In this measuring device 42, the pair of holding rollers 48 are set below the liquid level 52 of the liquid 46 stretched in the liquid tank 44. The position of the holding roller 48 in the liquid tank 44 is deeper than the position of the holding roller 16 in the liquid tank 10 of the measuring device 4 shown in FIG.

In this measuring device 42, the strip-shaped rubber member 2 transferred from the upstream side and passing through the delivery roller 54 changes its direction downward and is guided to the liquid 46 stretched in the liquid tank 44. The band-shaped rubber member 2 immersed in the liquid 46 changes its direction horizontally on the holding roller 48a on the upstream side and moves toward the holding roller 48b on the downstream side. The band-shaped rubber member 2 changes its direction upward on the holding roller 48a on the downstream side and moves toward the drawer roller 56. In the middle of this movement, the band-shaped rubber member 2 appears from the liquid 46 to the atmosphere side and is transferred to the downstream side by the pull-out roller 56.

In the measuring device 42, the band-shaped rubber member 2 is entirely submerged in the liquid 46 stretched in the liquid tank 44 by the pair of holding rollers 48. Therefore, both the first plane 8a and the second plane 8b of the strip-shaped rubber member 2 are immersed in the liquid 46.

In this measuring device 42, the probe 18 of the ultrasonic sensor 50 is arranged between the holding roller 48 on the upstream side and the holding roller 48 on the downstream side at a position facing the back surface of the band-shaped rubber member 2. Similar to the measuring device 4 shown in FIG. 1, the probe 18 emits ultrasonic waves toward the back surface of the band-shaped rubber member 2 and receives the reflected waves. In this measuring device 42, since the surface of the band-shaped rubber member 2 is also immersed in the liquid 46, the probe 18 may be arranged at a position facing the surface, and ultrasonic waves may be transmitted toward the surface.

Also in the method of measuring the band-shaped rubber member 2 using the measuring device 42, ultrasonic waves are transmitted in the liquid 46 toward the flat surface 8 of the band-shaped rubber member 2 immersed in the liquid 46. Since the attenuation of ultrasonic waves is suppressed, the reflected wave is received clearly. In this measuring method, the thickness of a plurality of sheets 6 laminated in the thickness direction can be measured safely and non-contactly. Since it is not necessary to cut the strip-shaped rubber member 2 to prepare a cross section of the strip-shaped rubber member 2 in order to grasp the thickness of each sheet 6, this measuring method does not involve loss of the strip-shaped rubber member 2. Since almost all of the manufactured strip-shaped rubber members 2 can be used as parts, this measurement method can contribute to the improvement of tire productivity.

In this measuring method, the thickness of the strip-shaped rubber member 2 in the conveyed state is measured. Therefore, when the strip-shaped rubber member 2 is immersed in the liquid 46, there is a risk of entraining air. This entrainment of air affects the propagation state of ultrasonic waves.

In this measuring device 42, the thickness of the band-shaped rubber member 2 is measured in a state where the entire band-shaped rubber member 2 is immersed in the liquid 46. Since the band-shaped rubber member 2 is set at a position deeper than the liquid level 52 of the liquid 46, the entrainment of air when the band-shaped rubber member 2 enters the liquid 46 is suppressed. The measuring method using the measuring device 42 can more accurately grasp the thickness of the plurality of sheets 6 laminated in the thickness direction. From this point of view, in this measuring method, it is preferable that both the first plane 8a and the second plane 8b of the strip-shaped rubber member 2 are immersed in the liquid 46 contained in the liquid tank 44.

As described above, according to the present invention, the thickness of each sheet 6 constituting the band-shaped rubber member 2 can be measured safely and without loss of the band-shaped rubber member 2. This method of measuring the thickness of the strip-shaped rubber member 2 can contribute to the improvement of tire productivity.

The embodiments disclosed this time are exemplary in all respects and are not restrictive. The technical scope of the present invention is not limited to the above-described embodiment, and the technical scope includes all modifications within a range equivalent to the configuration described in the claims.

The technique for measuring the thickness of the strip-shaped rubber member described above can also be applied to the manufacture of various tires.

2 ... Band-shaped rubber member 4, 42 ... Measuring device 6, 6a, 6b ... Sheet 8, 8a, 8b ... Flat surface 10, 44 ... Liquid tank 12, 46 ... Liquid 14, 50 ... Ultrasonic sensor 18 ... Probe 20 ... Controller 24 ... Piezoelectric element 26 ... Transmitter 28 ... Receiver 30, 30a, 30b, 30c ... Boundary 32 ... Atmosphere 52 ... Liquid level

Claims (3)

It is a method for measuring the thickness of a strip-shaped rubber member obtained by laminating a sheet made of a plurality of unvulcanized rubbers in the thickness direction.
A step of immersing at least one of the two flat surfaces of the band-shaped rubber member in the liquid contained in the liquid tank, and
A step of transmitting ultrasonic waves toward one plane of the band-shaped rubber member immersed in the liquid in the liquid and receiving the reflected waves.
The step of calculating the thickness of each sheet constituting the strip-shaped rubber member is included based on the propagation time from the transmission of the ultrasonic wave to the reception of the reflected wave and the propagation speed of the ultrasonic wave. , A method for measuring the thickness of a band-shaped rubber member. The method for measuring the thickness of a band-shaped rubber member according to claim 1, wherein the band-shaped rubber member is in a conveyed state. The method for measuring the thickness of a strip-shaped rubber member according to claim 1 or 2, wherein the plurality of sheets constituting the strip-shaped rubber member have different specific gravities.

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