JP5044975B2 - Pressure sensor for pressure measurement of unvulcanized tires - Google Patents

Description

  The present invention relates to a pressure-sensitive sensor for pressure measurement of a plastic material, and more particularly to a pressure-sensitive sensor for pressure measurement that makes it possible to measure a pressure acting on a plastic material with high accuracy.

  In the tire vulcanization process, ascertaining the pressure inside the unvulcanized tire is an important factor in quality control of product tires and tire design as disclosed in Patent Document 1 and the like. As a sensor for detecting the pressure with respect to such an unvulcanized rubber, as shown in FIG. 4, a pressure sensitive conductive rubber 2 such as silicon rubber containing a conductive filler is placed on an electrode substrate 3 and the pressure sensitive conductive rubber 2. There is known a pressure-sensitive sensor 1 for pressure measurement that detects the voltage between the electrodes 3a and 3b by utilizing the characteristic of changing the electric resistance depending on the magnitude of the load pressure. However, according to the results of the study by the present inventors, it has been found that this pressure-sensitive sensor causes a large measurement error when measuring the pressure applied to the unvulcanized tire in the tire vulcanization process.

As shown in FIG. 5A, the cause is that the pressure-sensitive sensor 1 is interposed between the unvulcanized tire 13 and the mold 14, and the pressure applied to the mold 14 on the unvulcanized tire 13 by a bladder (not shown). As shown in FIG. 5B, the unvulcanized tire 13 is plastically deformed so as to wrap around the pressure-sensitive conductive rubber 2, so that the pressure-sensitive conductive rubber 2 is restrained from free rubber deformation. Therefore, it was impossible to measure the accurate pressure.
JP 2003-181846 A

An object of the present invention is to provide a highly accurate pressure measurement for pressure-sensitive sensor of the unvulcanized tire to enable measurement at pressure measurement unvulcanized tire.

The pressure-sensitive sensor for pressure measurement of an unvulcanized tire of the present invention for achieving the above object is an unvulcanized tire that measures a pressure applied to the unvulcanized tire from a bladder in a vulcanization process of the unvulcanized tire. a pressure measuring pressure-sensitive sensor of the tire, on the pressure-sensitive conductive rubber which is laminated on the electrode substrate (3) (2), wherein the pressure-sensitive conductive rubber outer edge from the magnitude of which projects over 1mm in (2) A rigid plate (4) having an outer shape is laminated, and the rigid plate (4) is disposed so as to face the unvulcanized tire .

According to the pressure-sensitive sensor for pressure measurement of an unvulcanized tire of the present invention, a rigid plate having an outer shape larger than the pressure-sensitive conductive rubber surface is laminated on the outside of the pressure-sensitive conductive rubber. Is prevented from flowing around the pressure-sensitive conductive rubber, and a space can be secured around the pressure-sensitive conductive rubber. For this reason, since the pressure-sensitive conductive rubber is not restrained from being deformed when pressure is applied, the pressure change of the plastic material can be accurately measured.

FIG. 1 is an explanatory view showing parts of an example of a pressure sensor for pressure measurement according to the present invention in an exploded manner.
As shown in FIG. 1, a pressure-sensitive sensor 1 for pressure measurement includes an electrode substrate 3, a pressure-sensitive conductive rubber 2, and a rigid plate 4, and these three members are laminated together. The rigid plate 4 has an outer shape larger than the surface of the pressure-sensitive conductive rubber 2 and is laminated so as to protrude outward from the outer edge of the pressure-sensitive conductive rubber 2.

The pressure measuring pressure-sensitive sensor 1 of the above-described configuration, when used to measure pressure load unvulcanized rubber vulcanization of the unvulcanized tire is as shown in FIG. 2 (A) (B) .

  First, in a state where no pressure is applied to the unvulcanized tire set in the mold, the pressure-sensitive sensor 1 for pressure measurement, as shown in FIG. It is in a state of being interposed between the materials 12. When pressure is applied to the plastic material 11 (unvulcanized tire) toward the hard material 12 (mold) by the expansion of the bladder, the plastic material 11 causes the pressure-sensitive sensor 1 for pressure measurement as shown in FIG. Although deformed so as to wrap, the rigid plate 4 acts like an umbrella to prevent the plastic material 11 from flowing in, and a space is secured around the pressure-sensitive conductive rubber 2. Therefore, the pressure-sensitive conductive rubber 2 is not wrapped in the plastic material 11 and is not restrained from being deformed. For this reason, since the pressure-sensitive conductive rubber 2 is deformed in proportion to the pressure applied to the plastic material 11, the load pressure can be measured with high accuracy.

FIG. 3 shows the experimental results of detecting the pressure applied to the unvulcanized rubber with a press using the pressure sensor 1 for pressure measurement of the present invention described above and the conventional pressure sensor exemplified in FIG. Show. The pressure value measured by the pressure measuring pressure sensor 1 of the present invention was almost the same as the load value given by the press over time, but the pressure value obtained from the conventional sensor was It can be seen that the rubber deformation of the pressure-sensitive conductive rubber is constrained to be larger than the actual load value.

In the present invention, the pressure-sensitive conductive rubber 2 is not particularly limited as long as it is a material whose electric resistance changes according to the magnitude of pressure. For example, it is possible to exemplify polymeric piezoelectric materials such as silicon rubber containing conductive filler, polyvinylidene fluoride, and piezoelectric ceramics such as lead zirconate titanate. The shape of the pressure-sensitive conductive rubber 2 is preferably circular, and the outer diameter less than the minimum outer length of 5mm or more and the electrode substrate 3, it is preferable that the thickness is 0.5mm or more and 2mm or less. If the diameter and thickness of the pressure-sensitive conductive rubber 2 is outside the above range, it may affect the measurement.

The rigid plate 4 is not particularly limited, but may be composed of a thin metal plate, a plastic sheet or the like, and is preferably composed of an insulating material such as a plastic sheet. In addition, when using a metal thin plate, it is good to apply | coat an insulating paint to the part which contacts the pressure-sensitive conductive rubber 2 , or to affix it with an insulating film.

The shape of the rigid plate 4 is not particularly limited, but preferably a circular shape. The length of the rigid plate 4 protruding from the outer edge of the pressure-sensitive conductive rubber 2 is 1 mm or more . The length of output collision is less than 1 mm, there is a possibility that the plastic material 11 during pressing restrains the rubber deformation of the pressure-sensitive conductive rubber 2 goes around to the inside from the peripheral edge of the rigid plate 4.

The thickness of the rigid plate 4 is preferably set to 0.05mm or more and 0.2mm or less, more preferably to 0.08～0.1Mm. The thickness of the rigid plate 4, there is a possibility that can not be secured a space around the pressure-sensitive conductive rubber 2 in the pressurization is less than 0.05 mm, overreact measured pressure change exceeds 0.2mm There is a risk that the accuracy may decrease.

The electrode substrate 3 may be a substrate on which at least a pair of electrodes are provided at regular intervals. The electrode is generally printed with a conductive material.

Pressure measuring pressure-sensitive sensor 1 of the present invention, in the vulcanization step of the unvulcanized tire, used to measure the distribution of the pressure applied from the bladder against the unvulcanized tire in the mold.

When the pressure sensor 1 for pressure measurement of the present invention is used to measure the pressure applied to the mold from the bladder to the unvulcanized tire, the rigid plate 4 side of the pressure sensor 1 for pressure measurement is unvulcanized. Since it arrange | positions so that a tire may be opposed, a highly accurate measurement can be enabled.

Since the pressure received when the unvulcanized tire is pressed on the mold side differs depending on the position of the inner surface of the mold, the pressure measuring pressure sensors 1 may be installed in a plurality of locations. In particular, the pressure receiving order during the vulcanization process can be measured by dispersively arranging in the tread width direction of the mold and / or the radial direction of the side, and the peeling order when releasing the vulcanized tire. Can be measured.

It is explanatory drawing which decomposes | disassembles components and shows an example of the pressure sensor for pressure measurement of this invention. It is an example of the measuring method using the pressure sensitive sensor for pressure measurement of this invention, (A) is the state at the time of non-pressurization, (B) is explanatory drawing which shows the state at the time of pressurization typically. It is explanatory drawing which shows an example of the measurement result using the pressure-sensitive sensor for pressure measurement of this invention. It is explanatory drawing which shows an example of the conventional pressure sensor for pressure measurement. It is an example of the measuring method using the conventional pressure sensor for pressure measurement, (A) is the state at the time of non-pressurization, (B) is explanatory drawing which shows the state at the time of pressurization typically.

Explanation of symbols

1 Pressure-sensitive sensor for pressure measurement 2 Pressure-sensitive conductive rubber 3 Electrode substrate 4 Rigid plate 11 Plastic material

Claims (4)

A unvulcanized unvulcanized pressure measurement for pressure-sensitive sensor of the tire that measures the pressure acting on the unvulcanized tire from the bladder in the vulcanization step of the tire,
On the pressure-sensitive conductive rubber which is laminated on the electrode substrate (3) (2), with laminating the rigid plate (4) having a size of outer shape which projects above 1mm from the outer edge of the pressure-sensitive conductive rubber (2) A pressure-sensitive sensor for pressure measurement of an unvulcanized tire arranged so that the rigid plate (4) faces the unvulcanized tire . The rigid plate (4) is 0.05mm or more and 0.2mm or less in thickness unvulcanized pressure measurement for pressure-sensitive sensor of a tire according to claim 1, wherein the. The rigid plate (4) is unvulcanized pressure measurement for pressure-sensitive sensor of a tire according to 2 claim 1 or is made of an insulating material. The pressure-sensitive conductive rubber (2) is a circle having an outer diameter of 5 mm or more and not more than the minimum outer length of the electrode substrate (3) , and the thickness thereof is 0.5 mm or more and 2.0 mm or less. The pressure-sensitive sensor for pressure measurement of the unvulcanized tire according to any one of claims 1 to 3 .

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