WO2011074460A1 - Pneumatic circuit of tire testing device, tire testing device, and tire testing method - Google Patents

Pneumatic circuit of tire testing device, tire testing device, and tire testing method Download PDF

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Publication number
WO2011074460A1
WO2011074460A1 PCT/JP2010/072057 JP2010072057W WO2011074460A1 WO 2011074460 A1 WO2011074460 A1 WO 2011074460A1 JP 2010072057 W JP2010072057 W JP 2010072057W WO 2011074460 A1 WO2011074460 A1 WO 2011074460A1
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WIPO (PCT)
Prior art keywords
tire
air
pressure
temperature
test
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PCT/JP2010/072057
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French (fr)
Japanese (ja)
Inventor
徹 岡田
将雄 村上
浩一 本家
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株式会社神戸製鋼所
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Publication of WO2011074460A1 publication Critical patent/WO2011074460A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M17/00—Testing of vehicles
    • G01M17/007—Wheeled or endless-tracked vehicles
    • G01M17/02—Tyres
    • G01M17/021—Tyre supporting devices, e.g. chucks

Definitions

  • the present invention relates to a pneumatic circuit used in a tire testing device such as a tire uniformity machine, a tire testing device including the pneumatic circuit, and a tire testing method for testing a tire using the pneumatic circuit.
  • a tire test for determining the quality of a tire is performed by measuring the uniformity (uniformity) of the tire after the product has been manufactured.
  • the tire test is generally performed in the following procedure using a test apparatus disclosed in Patent Document 1.
  • the tire test apparatus of Patent Document 1 includes a pneumatic circuit that adjusts and supplies compressed air supplied from a factory air source to a tire seated on a rim, and the tire test is performed after the tire is inflated. Done.
  • This pneumatic circuit is provided with two systems of pipes that branch off in the middle.
  • One is a pipe of a bead seat system for inflating the tire in a short time and mounting the tire on the rim, and the other is a pipe of a test system used when testing the tire. Then, by switching between the bead seat system pipe and the test system pipe using a switching valve, the tire can be inflated through two pipe paths.
  • the tire that has flowed from the upstream of the inspection line is sandwiched between rims that are divided vertically.
  • the tire is inflated in a short time using the pipe of the bead seat system.
  • the air pressure of the compressed air supplied to the tire using the pipe of the bead seat system is generally higher (for example, about 400 kPa) than the test pressure (test air pressure) at the time of the tire test.
  • the tire is held at the bead seat pressure for about 1 second including the pressure rise time.
  • the flow path of the compressed air is switched from the bead seat system piping to the test system piping using a switching valve.
  • a pressure regulating valve is provided in the middle of the piping of this test system, and high-pressure compressed air can be reduced to a test pressure (for example, about 200 kPa). Therefore, the compressed air is supplied through the piping of the test system, so that the air pressure in the tire is adjusted to the test pressure.
  • the tire uniformity is measured by pressing the drum against the tire held at the test pressure and measuring the repulsive force generated in the tire using a load measuring device provided on the drum.
  • a servo pressure regulator may be used as shown in Patent Document 2.
  • the air pressure in the tire under test fluctuates even a little, the measurement result of uniformity greatly fluctuates. Therefore, it is important to keep the air pressure in the tire constant at the test pressure so that defective products are not put on the market and good products are not mistakenly determined as defective products.
  • the air pressure may decrease or rarely increase during the test.
  • Such a change in the air pressure in the tire may be as small as about 0.5 kPa or as large as about 1 kPa.
  • the change in the air pressure in the tire greatly affects the measurement result of uniformity.
  • Uniformity is measured by measuring the change in the repulsive force of the tire during one rotation of the tire.
  • the uniformity is measured by adding the change in the repulsive force due to this pressure change to the fluctuation characteristics of the repulsive force of the tire itself. Will be.
  • the phase relationship of the overlapping of the fluctuation characteristics varies depending on the measurement timing, so that the measurement result may be different at each test. Therefore, there is a possibility that the repeated stability of the test apparatus cannot be reliably determined, and it may be difficult to ensure the quality as the test apparatus / test line.
  • the servo pressure adjustment valve disclosed in Patent Document 2 is excellent in pressure adjustment accuracy but has low response. Therefore, even if the servo-type pressure regulating valve can cope with a gradual and steady fluctuation in air pressure, it is responsive enough to adjust the tire pressure in a timely manner within a tire test time of only about 1 second. Does not have.
  • an expensive one such as a servo-type pressure regulating valve is used, there is a problem that the price of the tire testing device increases. Therefore, it is not realistic to adjust the air pressure in the tire which fluctuates during the tire test with a tire test apparatus using a servo-type pressure regulating valve as in Patent Document 2.
  • the present invention has been made in view of the above-described problems, and by making the temperature of the air supplied to the tire higher than the outside air temperature, it is possible to suppress the fluctuation in air pressure that occurs during the tire test.
  • the object is to provide a pneumatic circuit of the device.
  • Another object of the present invention is to provide a tire testing apparatus and a tire testing method that can perform a tire test with high accuracy.
  • the present invention takes the following technical means. That is, the present invention is a pneumatic circuit of a tire testing apparatus including an air supply source that supplies air to a tire mounted between a pair of rims, and the temperature of the air supplied from the air supply source to the tire An air temperature raising mechanism for making the temperature higher than the temperature is provided.
  • the pneumatic circuit adjusts the pressure of the air supplied to the tire from the air supply source to a bead air pressure for inflating the tire and mounting the tire on a rim or a test air pressure used during a tire test lower than the bead air pressure.
  • the air temperature raising mechanism includes an adjustment valve and is configured to heat the air so that the temperature of the air supplied to the tire with the bead air pressure is higher than the outside air temperature.
  • the temperature of the air in the tire which has been high, is higher than the normal temperature, but is lower than that immediately after flowing into the tire with bead air pressure.
  • the temperature of the air in the tire when the test air pressure is set is normal temperature. It becomes below (below outside temperature). In other words, the temperature of the air in the tire immediately before the start of the tire test is lower than the temperature of the tire or rim that is normal temperature.
  • the tire test is performed in a state where there is a difference between the temperature of the air in the tire and the temperature of the tire or the rim (outside air temperature), the heat of the tire or the rim is transmitted to the air in the tire.
  • the temperature of the air in the tire rises and the pressure in the tire changes during the tire test. For example, when compressed air of 200 kPa is contained in tires or pipes by 0.05 m 3 , it is assumed that the temperature of the air rises by 1 ° C. from 25 ° C. to 26 ° C. during a measurement time of 1 second.
  • the temperature of the air in the tire may be equal to or lower than the normal temperature even when the difference between the bead air pressure and the test air pressure is large. Therefore, the temperature of the air at the test air pressure during the tire test is adjusted by preheating the high-pressure air of the first bead seat system in advance and compensating for the temperature drop when the bead air pressure is changed to the test air pressure. , It can be near the outside air temperature.
  • the air temperature raising mechanism can employ a configuration having a tank capable of storing air from the air supply source and a heat exchanger for heating the air in the tank.
  • the tank and the heat exchanger By providing the tank and the heat exchanger in this way, a large amount of air can be stored in the tank, and the air can be preheated by the heat exchanger therein. That is, the tire can be inflated by instantaneously supplying a large amount of heated air to the tire at high pressure, and the fitting characteristics (adhesion) between the tire and the rim can be improved.
  • the tire test apparatus provided with the above-described pneumatic circuit, by adjusting the temperature of the air supplied to the tire, it is possible to suppress the fluctuation of the air pressure generated during the tire test and to accurately measure the tire uniformity. .
  • the present invention also includes a step of inflating the tire by supplying air adjusted to bead air pressure to the tire and mounting the tire between a pair of rims, and a pressure lower than the bead air pressure on the tire mounted between the rims.
  • the pneumatic circuit of the tire testing apparatus of the present invention it is possible to suppress the fluctuation of the pneumatic pressure that occurs during the tire test by making the temperature of the air supplied to the tire higher than the outside air temperature.
  • the tire test apparatus and the tire test method of the present invention it is possible to accurately test a tire while suppressing fluctuations in air pressure that occur during the tire test.
  • a pneumatic circuit 1 according to an embodiment of the present invention and a tire testing apparatus 2 provided with the pneumatic circuit 1 will be described with reference to the drawings.
  • the tire testing apparatus 2 according to the present invention performs product inspection such as uniformity on the tire T that is finished with the product.
  • a uniformity machine is used as the tire testing apparatus 2.
  • Such a tire testing apparatus 2 has a configuration as shown in FIG. 1, for example.
  • the tire testing apparatus 2 includes a frame 3 provided in a tower shape on a floor surface, a pair of upper and lower tire shafts 4 and 5 attached to the frame 3, and these A pair of upper and lower rims 6 and 7 that are provided on the tire shafts 4 and 5 and fix the tire T are provided. These tire shafts 4 and 5 are disposed so as to be rotatable around the vertical axis. Further, a drum (not shown) having a simulated road surface formed on the outer peripheral surface is provided on the side of the tire T fixed by the rims 6 and 7. The drum can be driven and rotated about the vertical axis and can move horizontally so that the simulated road surface can be brought into contact with the tire T.
  • the tire shafts 4 and 5 of the tire testing device 2 are an upper tire shaft 4 provided on the upper side of the frame 3, and a lower tire shaft 5 that is coaxial with the upper tire shaft 4 and that can be moved up and down with a distance downward. ,have.
  • An upper rim 6 is provided at the lower end of the upper tire shaft 4, and a lower rim 7 is provided at the upper end of the lower tire shaft 5.
  • the upper and lower rims 6 and 7 are configured so that the tire T can be sandwiched and fixed between the upper and lower rims 6 and 7 by bringing the upper and lower tire shafts 4 and 5 closer to each other.
  • the tire shafts 4 and 5 or the drum are provided with a load measuring device for measuring the force generated in the running tire T, and the uniformity of the tire T can be measured.
  • the tire test apparatus 2 is provided with a pneumatic circuit 1 that adjusts the air pressure in the tire T by supplying compressed air into the tire T or discharging the compressed air from the tire T.
  • the pneumatic circuit 1 includes a pipe extending from the air supply source 10 into the tire T. This pipe communicates with the inside of the tire T through an air supply port 9 opened to the lower side of the air flow path 8 provided so as to penetrate the inside of the upper tire shaft 4 vertically.
  • the pneumatic circuit 1 can circulate compressed air into the tire T through the air flow path 8 and the air supply port 9.
  • the basic configuration of the pneumatic circuit 1 is directed to adjusting the compressed air generated by the air supply source 10 to a predetermined air pressure and supplying it to the tire T.
  • the pneumatic circuit 1 includes two routes to the tire T. One is a bead seat system 11 that inflates the tire T in a short time and presses the bead of the tire T against the rims 6 and 7, and the other is a test system 12 that is used when testing the tire T.
  • the air supply source 10 side is the upstream side and the tire T side is the downstream side.
  • the compressed air circulated through the bead sheet system 11 is adjusted to an air pressure (bead air pressure) of about 400 kPa, and the compressed air circulated through the test system 12 is about 200 kPa lower than the bead sheet system 11 ( The test air pressure is adjusted.
  • the bead seat system 11 and the test system 12 branch on the way from the air supply source 10 to the tire T, are adjusted to their respective air pressures, and then merge into one pipe again.
  • the test system 12 and the bead sheet system 11 showing this embodiment will be described in detail with reference to FIG.
  • the pneumatic circuit 1 when the pneumatic circuit 1 is viewed from the air supply source 10 side (upstream side) to the tire T side (downstream side), the pneumatic circuit 1 has two systems on the downstream side of the air temperature raising mechanism 21. It is branched to. One path is a bead sheet system 11 and the other path is a test system 12.
  • route until it branches toward the downstream side from the air supply source 10 is common, and the air which adjusts the air pressure in the bead seat system
  • the test system 12 is provided with a pressure regulating valve 13, a supply / discharge valve 14, a switching valve 15, a shutoff valve 16, and a pressure detection unit 17 in order from the upstream side to the downstream side.
  • the bead seat system 11 is provided with a bead pressure adjusting valve 22, a switching valve 15, a shutoff valve 16, and a pressure detection unit 17.
  • the shutoff valve 16 and the pressure detection unit 17 are provided in common for the test system 12 and the bead seat system 11.
  • the air supply source 10 is a supply source of factory air pressurized by a compressor (not shown).
  • the air supply source 10 generates compressed air that is equal to or higher in pressure than the air pressure (bead air pressure) when the tire T is inflated through the bead seat system 11.
  • An air filter 18 that collects dust and the like flowing from the air supply source 10 is provided on the downstream side of the air supply source 10.
  • a pressure gauge 19 for checking the pressure of compressed air generated by the air supply source 10 is provided on the downstream side of the air filter 18.
  • the pressure adjustment valve (test pressure adjustment valve) 13 is for adjusting the compressed air in the test system 12 to a predetermined pressure, and is composed of a pressure regulator. Further, a bead pressure adjusting valve 22 having the same configuration as the test pressure adjusting valve 13 is provided in the pipe of the bead seat system 11. The high-pressure compressed air generated by the air supply source 10 is reduced to bead air pressure (for example, 400 kPa) by the bead pressure adjusting valve 22.
  • the switching valve 15 switches the flow path of the compressed air between the test system 12 side and the bead seat system 11 side, and switches the air pressure in the tire T between the bead air pressure and the test air pressure.
  • the switching valve 15 of this embodiment operates (is in an ON state)
  • compressed air whose pressure is adjusted to bead air pressure is supplied into the tire T from the pipe of the bead seat system 11.
  • the switching valve 15 is not operated (is in an off state)
  • compressed air whose pressure is adjusted to the test air pressure is supplied into the tire T from the pipe of the test system 12.
  • the shutoff valve 16 is a directional control valve provided on the downstream side of the switching valve 15.
  • the flow path of the compressed air is shut off by switching the shutoff valve 16, and the compressed air can be contained in the pipe that reaches the tire T on the downstream side of the shutoff valve 16.
  • the supply / discharge valve 14 is a direction control valve provided on the downstream side of the test pressure adjustment valve 13. By switching the supply / exhaust valve 14, supply to the tire T and exhaust from the tire T (release to the atmosphere) are switched.
  • an air pressure sensor is provided as the pressure detection unit 17 on the downstream side of the supply / discharge valve 14.
  • the air pressure in the tire T may slightly change during the tire test. Since such a small change in air pressure is as small as 0.5 kPa to 1 kPa, the pressure adjustment accuracy is ⁇ 0.1% (for example, the adjustment system in the case of a pressure regulator rated at 1000 kPa is about ⁇ 1 kPa) Adjustment using only the test pressure adjusting valve 13 is difficult.
  • the air supplied from the air supply source 10 to the tire with the bead air pressure is preheated by the air temperature raising mechanism 21.
  • variation of the air pressure which arises during a tire test is suppressed by sending the air which became the temperature which exceeds outdoor temperature to a tire.
  • the air temperature raising mechanism 21 of the present embodiment is provided on the downstream side of the air supply source 10 (pressure gauge 19), and is a branch point between the bead seat system 11 and the test system 12. It is provided in the upstream piping.
  • the air temperature raising mechanism 21 includes a tank 23 disposed on the downstream side of the air supply source 10 and a heat exchanger 30 provided in the tank 23.
  • the heat exchanger 30 has a configuration in which a heat medium is passed through a tube to exchange heat.
  • the air pressure in the tire T can be prevented from changing during the tire test by raising the temperature of the air supplied to the tire T by the bead air pressure to a temperature exceeding the outside air temperature.
  • P1 atmospheric pressure
  • P1 is the pressure of the air in the tire T and the pressure in the pipe (hereinafter included in the tire T) before inflating by supplying air (that is, before inflating and before mounting on the rims 6 and 7).
  • the temperature is T1 (room temperature).
  • the pressure of the air supplied from the air supply source 10 is Pa (bead air pressure), and the temperature is Ta.
  • the temperature T2 of the air in the tire T after expansion when the compressed air is supplied from the air supply source 10 to the bead seat system 11 and the pressure in the tire T rises to the bead air pressure Pa is calculated.
  • the energy balance is expressed by equation (1).
  • Equation (1) m1 is the air mass before expansion, m2 is the air mass after expansion, u1 is the specific energy before expansion, and u2 is the specific energy after expansion.
  • M2-m1 represents the mass of air flowing in, and h represents the specific enthalpy of the air flowing in.
  • Equation (1) is , Expressed as equation (2).
  • equation (3) is obtained from equation (2).
  • the pressure of the air supplied from the air supply source 10 is 400 kPa (gauge pressure), and the temperature of the air is 20 ° C., which is room temperature (outside air temperature). Further, the air before expansion in the tire T is set to atmospheric pressure and 20 ° C. (outside air temperature).
  • P1 100 kPa (absolute pressure)
  • T1 293K (absolute temperature)
  • Ta 293K (absolute temperature)
  • ⁇ 1.4
  • the switching valve 15 is switched so that the air pressure in the tire T changes from the bead air pressure to the test air pressure.
  • the switching valve 15 is switched, that is, while the bead air pressure is maintained so that the air pressure in the tire T becomes the bead air pressure
  • the heat of the air in the tire T By being transmitted to the tire T, the temperature of the air in the tire T decreases.
  • the amount of decrease in the temperature of the air in the tire T is such that the larger the difference between the temperature of the rims 6 and 7 and the tire T and the temperature of the air in the tire T, and the longer the time during which the bead air pressure is maintained. large.
  • the temperature of the air in the tire T is very high. Therefore, the temperature of the air in the tire T may decrease by about 50 ° C. even if the time for holding the bead air pressure is short. In this embodiment, the temperature of the air in the tire T when the switching valve 15 is switched was 57 ° C.
  • the absolute temperature T2 at the test pressure is 86% of T1. Therefore, if the temperature in the tire T at the time of bead air pressure (when the switching valve 15 is switched) is 57 ° C. (330 K), the temperature of the air in the tire T becomes 11 ° C. when the test air pressure is reached. The temperature of the air in the tire T at this test air pressure is 11 ° C., which is lower than the outside air temperature 20 ° C.
  • the tire test is performed in a state where the temperature of the air in the tire T is lower than the outside air temperature
  • the heat of the rubber T and the metal rims 6 and 7 of the normal temperature tire T is transmitted into the tire T, and the tire test is performed.
  • the air temperature of the tire T rises inside. If the temperature of the air in the tire T rises during the tire test, the pressure of the air in the tire T changes, and the pressure of the air in the tire T increases.
  • the temperature difference between the air in the tire T and the tire T and the rims 6 and 7 increases, the amount of heat transfer increases, and the temperature of the air in the tire T having a small heat capacity increases steadily. The pressure increases.
  • air whose temperature is increased by the air temperature raising mechanism 21 so as to exceed the outside air temperature is supplied to the piping system as the air supplied from the air supply source 10 to the tire T by the bead air pressure. It is characterized by pouring.
  • the air supplied from the air supply source 10 into the tire T at the bead air pressure (gauge pressure of 400 kPa) is heated by the heat exchanger 30 in the tank 23.
  • the temperature of the air in the tank 23 is increased by 10 ° C. from the outside air temperature (normal temperature), as described above, the temperature of the air in the tire T at the bead air pressure (when the switching valve 15 is switched) becomes 67 ° C.
  • the pressure of the air in the tire T is lowered from the bead air pressure to the test air pressure of 200 kPa (gauge pressure)
  • the temperature of the air in the tire T becomes 19.4 ° C., which is substantially equal to the outside air temperature. In this case, the temperature change during the tire test is slight, and the pressure change hardly occurs.
  • the final temperature in the tire T is affected by the temperature change due to heat transfer in addition to the temperature change obtained by the above calculation. It is desirable that the temperature setting of the cooled air is experimentally examined for an appropriate value in each tire testing device 2. Further, it has been experimentally confirmed that the temperature change and the pressure change are moderate if the temperature in the tire T is within a range of ⁇ 5 ° C. of the outside air temperature when the bead air pressure is changed to the test air pressure.
  • the tire test is performed in the following procedure. That is, when performing a tire test, first, the air pressure in the tire T is adjusted to the bead air pressure via the pipe of the bead seat system 11, and air heated to a temperature exceeding the outside air temperature by the heat exchanger 30 (for example, 30 ° C. The tire T is inflated in a short time, and the bead portion of the tire T is firmly attached to the rims 6 and 7.
  • the switching valve 15 When the tire T is mounted, the switching valve 15 is turned on and the shutoff valve 16 is turned off, whereby the air flow path of the test system 12 is closed and the air flow path of the bead seat system 11 is opened. And the tire T expand
  • the temperature in the tire T immediately after the tire T is expanded with the bead air pressure is 117 ° C.
  • the switching valve 15 is turned off while the supply / discharge valve 14 is on and the shutoff valve 16 is off. In this way, the flow path of the compressed air is switched to the test system 12 and the air in the tire T is exhausted outside the air flow path 8.
  • a test pressure adjusting valve 13 is provided in the piping of the test system 12, and the pressure of the compressed air in the tire T, which has been set to bead air pressure, is switched to the test air pressure. While the bead air pressure is switched to the test air pressure, the heat of the air of the tire T is transmitted to the tire T and the rims 6 and 7, so that the temperature of the air gradually decreases.
  • the temperature of the air in the tire T immediately after switching to the test air pressure is 67 ° C.
  • the air temperature raising mechanism 21 that heats the air supplied from the air supply source 10 to the tire T and makes the temperature of the air higher than the outside air temperature, the air pressure that is difficult to adjust with the pressure regulator is obtained. Variations can be suppressed. Therefore, the tire T can be maintained at the test air pressure during the tire test, and the uniformity can be accurately measured.
  • the present invention is not limited to the above-described embodiments, and the shape, structure, material, combination, and the like of each member can be appropriately changed without changing the essence of the invention.
  • a uniformity machine is cited as an example of the tire testing apparatus 2.
  • the pneumatic circuit 1 of the present invention can also be used in a tire testing apparatus that performs evaluations other than uniformity.
  • the air temperature raising mechanism 21 of the embodiment heated the air by the heat exchanger 30 and made the temperature of the air supplied to the tire T higher than the outside air temperature, instead, before supplying the bead air, The temperature of the air may be raised by adiabatically compressing the air in the tank 23.

Abstract

Provided is a tire testing device capable of preventing the change of air pressure caused during a tire test by regulating the temperature of air to be supplied to a tire. A pneumatic circuit (1) of a tire testing device (2) is provided with an air supply source (10) for supplying air to a tire (T) mounted between a pair of rims (6, 7), and a pressure regulation valve (13). The pressure regulation valve (13) regulates the pressure of air to be supplied from the air supply source (10) to the tire (T) to bead air pressure for inflating the tire (T) and mounting the tire to the rims (6, 7) or test air pressure that is lower than the bead air pressure and used during the tire test. The pneumatic circuit (1) is further provided with an air temperature increase mechanism (21) for heating the air to be supplied to the tire at the bead air pressure to a temperature higher than the outside air temperature.

Description

タイヤ試験装置の空気圧回路、タイヤ試験装置及びタイヤ試験方法Pneumatic circuit of tire test apparatus, tire test apparatus and tire test method
　本発明は、例えば、タイヤユニフォーミティマシンなどのタイヤ試験装置に用いられる空気圧回路、この空気圧回路を備えたタイヤ試験装置、及びこの空気圧回路を用いてタイヤの試験を行うタイヤ試験方法に関する。 The present invention relates to a pneumatic circuit used in a tire testing device such as a tire uniformity machine, a tire testing device including the pneumatic circuit, and a tire testing method for testing a tire using the pneumatic circuit.
　従来、製品上がりのタイヤのユニフォーミティ（均一性）などを計測することにより、タイヤの良否を判定するタイヤ試験（ユニフォーミティ検査）が行われている。例えば乗用車用のタイヤについてユニフォーミティを計測する場合、タイヤ試験は、概ね特許文献１に示される試験装置を用いて、以下のような手順で行われる。
　特許文献１のタイヤ試験装置は、リム上に着座するタイヤに対して工場空気源から供給された圧縮空気を圧力調整して供給する空気圧回路を備えており、タイヤ試験はタイヤを膨らませた後で行われる。この空気圧回路は、途中で分岐した２系統の配管を備えている。一方はタイヤを短時間で膨らまし、タイヤをリムに装着するためのビードシート系統の配管であり、他方はタイヤを試験する際に用いられるテスト系統の配管である。そして、これらのビードシート系統の配管とテスト系統の配管とを切替弁を用いて切り替えることにより、２系統の配管経路でタイヤを膨らますことができる。 Conventionally, a tire test (uniformity inspection) for determining the quality of a tire is performed by measuring the uniformity (uniformity) of the tire after the product has been manufactured. For example, when measuring uniformity for a tire for a passenger car, the tire test is generally performed in the following procedure using a test apparatus disclosed in Patent Document 1.
The tire test apparatus of Patent Document 1 includes a pneumatic circuit that adjusts and supplies compressed air supplied from a factory air source to a tire seated on a rim, and the tire test is performed after the tire is inflated. Done. This pneumatic circuit is provided with two systems of pipes that branch off in the middle. One is a pipe of a bead seat system for inflating the tire in a short time and mounting the tire on the rim, and the other is a pipe of a test system used when testing the tire. Then, by switching between the bead seat system pipe and the test system pipe using a switching valve, the tire can be inflated through two pipe paths.
　このタイヤ試験装置でタイヤ試験を行う場合、まず検査ラインの上流から流れてきたタイヤが、上下に分割されたリムで挟み込まれる。次に、ビードシート系統の配管を用いてタイヤが短時間で膨らまされる。このとき、ビードシート系統の配管を用いてタイヤに供給される圧縮空気の空気圧は、タイヤ試験時のテスト圧（テスト空気圧）よりも高圧（例えば、約４００ｋＰａ）であるのが一般的である。タイヤは、圧力上昇時間も含めて前記ビードシート圧に１秒程度にわたり保持される。 When performing a tire test using this tire test apparatus, first, the tire that has flowed from the upstream of the inspection line is sandwiched between rims that are divided vertically. Next, the tire is inflated in a short time using the pipe of the bead seat system. At this time, the air pressure of the compressed air supplied to the tire using the pipe of the bead seat system is generally higher (for example, about 400 kPa) than the test pressure (test air pressure) at the time of the tire test. The tire is held at the bead seat pressure for about 1 second including the pressure rise time.
　次に、このタイヤ試験装置では、圧縮空気の流路が、ビードシート系統の配管からテスト系統の配管に切替弁を用いて切り替えられる。このテスト系統の配管の途中には圧力調整弁が設けられており、高圧の圧縮空気をテスト圧（例えば、約２００ｋＰａ）に減圧可能となっている。それゆえ、圧縮空気がテスト系統の配管を通じて供給されることで、タイヤ内の空気圧がテスト圧に調整される。そして、テスト圧に保持されたタイヤにドラムを押し付けて、ドラムに設けられた荷重計測器を用いてタイヤに発生する反発力を計測することにより、タイヤのユニフォーミティが計測される。 Next, in this tire test apparatus, the flow path of the compressed air is switched from the bead seat system piping to the test system piping using a switching valve. A pressure regulating valve is provided in the middle of the piping of this test system, and high-pressure compressed air can be reduced to a test pressure (for example, about 200 kPa). Therefore, the compressed air is supplied through the piping of the test system, so that the air pressure in the tire is adjusted to the test pressure. The tire uniformity is measured by pressing the drum against the tire held at the test pressure and measuring the repulsive force generated in the tire using a load measuring device provided on the drum.
　なお、上述した圧力調整弁としては、特許文献２に示されるようにサーボ式の圧力レギュレータが用いられることもある。 In addition, as the pressure regulating valve described above, a servo pressure regulator may be used as shown in Patent Document 2.
日本国特公平６－９５０５７号公報Japanese Patent Publication No. 6-95057 米国特許第５２９１７７６号明細書US Pat. No. 5,291,776
　ところで、タイヤ試験においては、試験中のタイヤ内の空気圧が少しでも変動するとユニフォーミティの計測結果が大きく変動することが知られている。それゆえ、不良品を市場に出さないためにも、また間違って良品を不良品と判定しないためにも、タイヤ内の空気圧をテスト圧に一定に保つ事が重要である。ところが、実際のタイヤ試験においては、テスト中に空気圧が低下したり、まれに上昇したりすることがある。 By the way, in the tire test, it is known that if the air pressure in the tire under test fluctuates even a little, the measurement result of uniformity greatly fluctuates. Therefore, it is important to keep the air pressure in the tire constant at the test pressure so that defective products are not put on the market and good products are not mistakenly determined as defective products. However, in an actual tire test, the air pressure may decrease or rarely increase during the test.
　このようなタイヤ内の空気圧の変化は、０．５ｋＰａ程度と小さい場合もあれば、１ｋＰａ程度と大きい場合もある。しかし、空気圧の変化が０．５ｋＰａ程度と小さい場合であっても、タイヤ内の空気圧の変化はユニフォーミティの計測結果に大きく影響する。ユニフォーミティはタイヤ１回転におけるタイヤの反発力の変化を計測することにより計測されるものであり、タイヤ自体が有する反発力の変動特性に、この圧力変化による反発力の変化が加わった値で計測されてしまう。同一のタイヤにおいても、計測タイミングによって変動特性の重なりの位相関係が変わることにより、試験の度に計測結果が異なる場合がある。したがって、試験装置の繰り返し安定性が確実に判別できなくなる可能性があり、試験装置・試験ラインとしての品質確保が困難となるおそれがある。 Such a change in the air pressure in the tire may be as small as about 0.5 kPa or as large as about 1 kPa. However, even if the change in the air pressure is as small as about 0.5 kPa, the change in the air pressure in the tire greatly affects the measurement result of uniformity. Uniformity is measured by measuring the change in the repulsive force of the tire during one rotation of the tire. The uniformity is measured by adding the change in the repulsive force due to this pressure change to the fluctuation characteristics of the repulsive force of the tire itself. Will be. Even in the same tire, the phase relationship of the overlapping of the fluctuation characteristics varies depending on the measurement timing, so that the measurement result may be different at each test. Therefore, there is a possibility that the repeated stability of the test apparatus cannot be reliably determined, and it may be difficult to ensure the quality as the test apparatus / test line.
　しかしながら、特許文献１のタイヤ試験装置に使われるような一般的な圧力調整弁で上述のような微小な空気圧の変化を調整することは困難である。なぜなら、一般的な圧力調整弁の圧力調整範囲は１０００ｋＰａ程度であり、圧力調整精度は良くても±０．１％つまり１ｋＰａ程度である。したがって、タイヤ試験中に０．５ｋＰａ程度で変動するタイヤ内の空気圧を、１ｋＰａ程度の圧力調整精度しかない圧力調整弁を用いて調整することは不可能である。 However, it is difficult to adjust the minute change in air pressure as described above with a general pressure regulating valve used in the tire testing apparatus of Patent Document 1. This is because the pressure adjustment range of a general pressure adjustment valve is about 1000 kPa, and the pressure adjustment accuracy is ± 0.1%, that is, about 1 kPa at best. Therefore, it is impossible to adjust the air pressure in the tire that fluctuates at about 0.5 kPa during the tire test using a pressure adjustment valve that has only a pressure adjustment accuracy of about 1 kPa.
　一方、特許文献２に開示されたサーボ式の圧力調整弁は、圧力調整精度には優れるものの応答性が低い。それゆえ、サーボ式の圧力調整弁は、緩やかで定常的な空気圧の変動には対応できても、１秒程度しかないタイヤ試験時間内でタイムリーにタイヤ内の空気圧を調整できるほどの応答性を有していない。また、サーボ式の圧力調整弁のように高価なものを用いると、タイヤ試験装置の価格が高騰するという問題もある。それゆえ、特許文献２のようにサーボ式の圧力調整弁を用いたタイヤ試験装置で、タイヤ試験中に変動するタイヤ内の空気圧を調整することは現実的でない。 On the other hand, the servo pressure adjustment valve disclosed in Patent Document 2 is excellent in pressure adjustment accuracy but has low response. Therefore, even if the servo-type pressure regulating valve can cope with a gradual and steady fluctuation in air pressure, it is responsive enough to adjust the tire pressure in a timely manner within a tire test time of only about 1 second. Does not have. In addition, when an expensive one such as a servo-type pressure regulating valve is used, there is a problem that the price of the tire testing device increases. Therefore, it is not realistic to adjust the air pressure in the tire which fluctuates during the tire test with a tire test apparatus using a servo-type pressure regulating valve as in Patent Document 2.
　本発明は、上述の問題に鑑みてなされたものであり、タイヤに供給される空気の温度を外気温度よりも高くすることによって、タイヤ試験中に生じる空気圧の変動を抑えることができる、タイヤ試験装置の空気圧回路を提供することを目的とする。
　また、本発明は、精度良くタイヤ試験を行うことができるタイヤ試験装置及びタイヤ試験方法を提供することを目的とする。 The present invention has been made in view of the above-described problems, and by making the temperature of the air supplied to the tire higher than the outside air temperature, it is possible to suppress the fluctuation in air pressure that occurs during the tire test. The object is to provide a pneumatic circuit of the device.
Another object of the present invention is to provide a tire testing apparatus and a tire testing method that can perform a tire test with high accuracy.
　前記目的を達成するため、本発明は次の技術的手段を講じている。
　すなわち、本発明は、一対のリム間に装着されるタイヤに空気を供給する空気供給源を備えるタイヤ試験装置の空気圧回路であって、前記空気供給源からタイヤに供給される空気の温度を外気温度よりも高くする空気昇温機構を備えることを特徴とする。 In order to achieve the object, the present invention takes the following technical means.
That is, the present invention is a pneumatic circuit of a tire testing apparatus including an air supply source that supplies air to a tire mounted between a pair of rims, and the temperature of the air supplied from the air supply source to the tire An air temperature raising mechanism for making the temperature higher than the temperature is provided.
　前記空気圧回路は、前記空気供給源からタイヤに供給される空気の圧力を、前記タイヤを膨らませてリムに装着するためのビード空気圧又はこのビード空気圧より低圧なタイヤ試験時に用いるテスト空気圧に調整する圧力調整弁を備え、前記空気昇温機構は、前記ビード空気圧でタイヤに供給される空気の温度が外気温度よりも高くなるように、当該空気を加熱するように構成されていることが好ましい。 The pneumatic circuit adjusts the pressure of the air supplied to the tire from the air supply source to a bead air pressure for inflating the tire and mounting the tire on a rim or a test air pressure used during a tire test lower than the bead air pressure. It is preferable that the air temperature raising mechanism includes an adjustment valve and is configured to heat the air so that the temperature of the air supplied to the tire with the bead air pressure is higher than the outside air temperature.
　本発明者の研究により、タイヤ試験中の圧力上昇には、タイヤ内の空気の温度が影響していることが明らかになった。
　ここで、タイヤ試験中の圧力上昇について詳しく説明する。
　まず、タイヤの試験を行うに際して、従来の方法では、常温の空気をビード空気圧でタイヤに流入させる。そのため、もともとタイヤ内に存在していた空気は圧縮されて断熱圧縮により温度上昇するので、タイヤ内の空気の温度は高温となる。その後、ビード空気圧に保持する間（ビード保持時間）は、タイヤ内の空気の熱がタイヤやリムに伝達されるために、タイヤ内の空気の温度は下降する。その結果、高温となっていたタイヤ内の空気の温度は常温よりも高温であるものの、ビード空気圧でタイヤに流入させた直後に比べると低下する。ビード保持時間が長くなればなるほど、タイヤ内の空気の温度の低下量は大きくなる。 The study by the present inventor has revealed that the pressure increase during the tire test is affected by the temperature of the air in the tire.
Here, the pressure increase during the tire test will be described in detail.
First, when testing a tire, in a conventional method, air at normal temperature is caused to flow into the tire with bead air pressure. Therefore, the air originally present in the tire is compressed and the temperature rises due to adiabatic compression, so the temperature of the air in the tire becomes high. After that, while the bead air pressure is maintained (bead holding time), the heat of the air in the tire is transmitted to the tire and the rim, so the temperature of the air in the tire decreases. As a result, the temperature of the air in the tire, which has been high, is higher than the normal temperature, but is lower than that immediately after flowing into the tire with bead air pressure. The longer the bead retention time, the greater the amount of decrease in the temperature of the air in the tire.
　その後、ビード空気圧からテスト空気圧に移行すると、タイヤ内圧力は急激に下がり、断熱膨張によりタイヤ内の空気の温度は低下する。このとき、例えばビード保持時間が長く、ビード空気圧に保持されている間のタイヤ内の空気の温度低下が大きいと、テスト空気圧にしたとき（タイヤ試験開始直前）のタイヤ内の空気の温度は常温以下（外気温度以下）になる。言い換えれば、タイヤ試験開始直前におけるタイヤ内の空気の温度は、常温であるタイヤやリムの温度よりも低くなる。 After that, when the bead air pressure is changed to the test air pressure, the pressure in the tire decreases rapidly, and the temperature of the air in the tire decreases due to adiabatic expansion. At this time, for example, if the bead holding time is long and the temperature drop of the air in the tire is large while being held at the bead air pressure, the temperature of the air in the tire when the test air pressure is set (just before starting the tire test) is normal temperature. It becomes below (below outside temperature). In other words, the temperature of the air in the tire immediately before the start of the tire test is lower than the temperature of the tire or rim that is normal temperature.
　このように、タイヤ内の空気の温度とタイヤやリムの温度（外気温度）との差がある状態でタイヤ試験を行ってしまうと、タイヤやリムの熱がタイヤ内の空気に伝達されて当該タイヤ内の空気の温度が上昇し、タイヤ試験中にタイヤ内の圧力が変化してしまう。
　例えば、タイヤや配管に２００ｋＰａの圧縮空気が０．０５ｍ３封じ込められている場合、計測時間１秒の間にその空気の温度が２５℃から２６℃に１℃上がると仮定する。 As described above, if the tire test is performed in a state where there is a difference between the temperature of the air in the tire and the temperature of the tire or the rim (outside air temperature), the heat of the tire or the rim is transmitted to the air in the tire. The temperature of the air in the tire rises and the pressure in the tire changes during the tire test.
For example, when compressed air of 200 kPa is contained in tires or pipes by 0.05 m 3 , it is assumed that the temperature of the air rises by 1 ° C. from 25 ° C. to 26 ° C. during a measurement time of 1 second.
　ここで、体積変化は少ないと考えると、ボイルシャルルの法則（圧力と体積の積を絶対温度で割った値は一定）より、圧力は、２００ｋＰａ×１Ｋ／２９７Ｋ＝０．７ｋＰａ上昇する。また、タイヤ試験開始直前のタイヤ内の空気の温度（テスト空気圧にしたときのタイヤ内の空気の温度）が、リムやタイヤの温度（外気温度）に比べて低いほど、計測時間中のタイヤ内の空気の温度変化量が増加して、圧力の変化量が増加することもわかる。 Here, if the volume change is considered to be small, the pressure increases by 200 kPa × 1 K / 297 K = 0.7 kPa according to Boyle's law (the value obtained by dividing the product of pressure and volume by the absolute temperature is constant). Also, the lower the temperature of the air in the tire just before the start of the tire test (the temperature of the air in the tire when the test air pressure is used) compared to the temperature of the rim or tire (outside air temperature), the inside of the tire during the measurement time It can also be seen that the amount of change in pressure increases as the amount of change in air temperature increases.
　なお、ビード空気圧からテスト空気圧に移行させる際に、ビード空気圧とテスト空気圧との差が大きい場合にも、タイヤ内の空気の温度は常温以下になることがある。
　よって、最初のビードシート系統の高圧の空気を予め昇温しておき、ビード空気圧からテスト空気圧に移行したときの温度降下を補償することによって、タイヤ試験を行う際のテスト空気圧の空気の温度を、外気温度付近にすることができる。 Note that when the bead air pressure is changed to the test air pressure, the temperature of the air in the tire may be equal to or lower than the normal temperature even when the difference between the bead air pressure and the test air pressure is large.
Therefore, the temperature of the air at the test air pressure during the tire test is adjusted by preheating the high-pressure air of the first bead seat system in advance and compensating for the temperature drop when the bead air pressure is changed to the test air pressure. , It can be near the outside air temperature.
　これにより、計測時間中におけるタイヤ内空気の温度変化が少なくなり、タイヤ試験中に生じる空気圧の変動を抑えることができる。 This reduces the temperature change in the tire air during the measurement time, and can suppress fluctuations in air pressure that occur during the tire test.
　また、前記空気昇温機構は、前記空気供給源からの空気を貯蔵可能なタンクと、このタンク内の空気を加熱する熱交換器と、を有する構成を採用することができる。 Further, the air temperature raising mechanism can employ a configuration having a tank capable of storing air from the air supply source and a heat exchanger for heating the air in the tank.
　このようにタンクと熱交換器とを設けることで、大量の空気をタンク内にためて、その中で熱交換器によって空気を予め加熱しておくことができる。つまり、加熱された空気を瞬間的に高圧で大量にタイヤに送り込むことによりタイヤを膨らませることができ、タイヤとリムのフィッティング特性（密着性）を高めることが可能となる。 By providing the tank and the heat exchanger in this way, a large amount of air can be stored in the tank, and the air can be preheated by the heat exchanger therein. That is, the tire can be inflated by instantaneously supplying a large amount of heated air to the tire at high pressure, and the fitting characteristics (adhesion) between the tire and the rim can be improved.
　さらに、上述の空気圧回路を備えたタイヤ試験装置によれば、タイヤに供給される空気の温度を調整することで、タイヤ試験中に生じる空気圧の変動を抑え、タイヤのユニフォーミティを精度良く計測できる。 Furthermore, according to the tire test apparatus provided with the above-described pneumatic circuit, by adjusting the temperature of the air supplied to the tire, it is possible to suppress the fluctuation of the air pressure generated during the tire test and to accurately measure the tire uniformity. .
　また、本発明は、ビード空気圧に調整された空気をタイヤに供給することにより前記タイヤを膨らませて一対のリム間に装着する工程と、前記リム間に装着された前記タイヤに前記ビード空気圧より低圧なテスト空気圧に調整された空気を供給した状態で前記タイヤの特性を計測する工程と、を有するタイヤ試験方法であって、外気温度よりも温度を高くした空気を、前記ビード空気圧で前記タイヤに供給することを特徴とする。 The present invention also includes a step of inflating the tire by supplying air adjusted to bead air pressure to the tire and mounting the tire between a pair of rims, and a pressure lower than the bead air pressure on the tire mounted between the rims. A method for measuring the characteristics of the tire in a state in which air adjusted to a suitable test air pressure is supplied, the air having a temperature higher than the outside air temperature being applied to the tire with the bead air pressure. It is characterized by supplying.
　このように、ビード空気圧でタイヤに供給される空気の温度を、外気温度を上回る温度に予めすることにより、タイヤ試験時におけるタイヤ内の空気圧の変動を抑えることができ、タイヤ試験を精度良く行うことができる。 As described above, by preliminarily setting the temperature of the air supplied to the tire with the bead air pressure to a temperature exceeding the outside air temperature, it is possible to suppress the fluctuation of the air pressure in the tire at the time of the tire test and perform the tire test with high accuracy. be able to.
　本発明のタイヤ試験装置の空気圧回路によれば、タイヤに供給される空気の温度を外気温度より高くすることによって、タイヤ試験中に生じる空気圧の変動を抑えることができる。また、本発明のタイヤ試験装置及びタイヤ試験方法によれば、タイヤ試験中に生じる空気圧の変動を抑制して、タイヤの試験を精度良く行うことができる。 According to the pneumatic circuit of the tire testing apparatus of the present invention, it is possible to suppress the fluctuation of the pneumatic pressure that occurs during the tire test by making the temperature of the air supplied to the tire higher than the outside air temperature. In addition, according to the tire test apparatus and the tire test method of the present invention, it is possible to accurately test a tire while suppressing fluctuations in air pressure that occur during the tire test.
タイヤ試験装置の正面図である。It is a front view of a tire testing device. 空気圧回路の基本構成を示す図である。It is a figure which shows the basic composition of a pneumatic circuit. 一実施形態の空気圧回路を示す図である。It is a figure which shows the pneumatic circuit of one Embodiment.
　本発明の一実施形態の空気圧回路１及びこの空気圧回路１が設けられたタイヤ試験装置２を、図面に基づき説明する。
　本発明のタイヤ試験装置２は、製品上がりのタイヤＴに対してユニフォーミティなどの製品検査を行う。本実施形態では、タイヤ試験装置２としてユニフォーミティマシンが用いられている。このようなタイヤ試験装置２は、例えば図１に示されるような構成を有する。 A pneumatic circuit 1 according to an embodiment of the present invention and a tire testing apparatus 2 provided with the pneumatic circuit 1 will be described with reference to the drawings.
The tire testing apparatus 2 according to the present invention performs product inspection such as uniformity on the tire T that is finished with the product. In this embodiment, a uniformity machine is used as the tire testing apparatus 2. Such a tire testing apparatus 2 has a configuration as shown in FIG. 1, for example.
　図１に模式的に示されるように、タイヤ試験装置２は、床面に塔状に設けられたフレーム３と、このフレーム３に取り付けられた上下１組のタイヤ軸４、５と、これらのタイヤ軸４、５に設けられてタイヤＴを固定する上下一対のリム６、７と、を備えている。これらのタイヤ軸４、５は上下軸回りに回転自在に配置されている。さらに、リム６、７で固定されたタイヤＴの側方には、外周面に模擬路面が形成されたドラム（図示略）が備えられている。このドラムは、上下軸回りに駆動回転可能であると共に、タイヤＴに模擬路面を接触できるように水平に移動可能な構成となっている。 As schematically shown in FIG. 1, the tire testing apparatus 2 includes a frame 3 provided in a tower shape on a floor surface, a pair of upper and lower tire shafts 4 and 5 attached to the frame 3, and these A pair of upper and lower rims 6 and 7 that are provided on the tire shafts 4 and 5 and fix the tire T are provided. These tire shafts 4 and 5 are disposed so as to be rotatable around the vertical axis. Further, a drum (not shown) having a simulated road surface formed on the outer peripheral surface is provided on the side of the tire T fixed by the rims 6 and 7. The drum can be driven and rotated about the vertical axis and can move horizontally so that the simulated road surface can be brought into contact with the tire T.
　以降の説明において、図１の紙面の上下を、タイヤ試験装置２を説明する際の上下と呼ぶ。
　タイヤ試験装置２のタイヤ軸４、５は、フレーム３の上側に設けられる上タイヤ軸４と、この上タイヤ軸４と同軸に、下方に距離をあけて昇降自在に設けられる下タイヤ軸５と、を有している。上タイヤ軸４の下端には上リム６が設けられ、下タイヤ軸５の上端には下リム７が設けられている。上下リム６、７は、上下タイヤ軸４、５を互いに接近させることにより、上下リム６、７間にタイヤＴを挟み込んで固定できるように構成されている。 In the following description, the upper and lower sides in FIG. 1 are referred to as the upper and lower sides when the tire testing apparatus 2 is described.
The tire shafts 4 and 5 of the tire testing device 2 are an upper tire shaft 4 provided on the upper side of the frame 3, and a lower tire shaft 5 that is coaxial with the upper tire shaft 4 and that can be moved up and down with a distance downward. ,have. An upper rim 6 is provided at the lower end of the upper tire shaft 4, and a lower rim 7 is provided at the upper end of the lower tire shaft 5. The upper and lower rims 6 and 7 are configured so that the tire T can be sandwiched and fixed between the upper and lower rims 6 and 7 by bringing the upper and lower tire shafts 4 and 5 closer to each other.
　タイヤ軸４、５又はドラムには、走行中のタイヤＴに発生する力を計測する荷重計測器などが設けられており、タイヤＴのユニフォーミティを計測できるようになっている。
　ところで、上述のようなタイヤ試験を行う際には、タイヤＴ内の空気圧を、所定の空気圧に調整しておく必要がある。そこで、タイヤ試験装置２には、タイヤＴ内に圧縮空気を供給したりタイヤＴから圧縮空気を排出したりすることによりタイヤＴ内の空気圧を調整する空気圧回路１が設けられている。 The tire shafts 4 and 5 or the drum are provided with a load measuring device for measuring the force generated in the running tire T, and the uniformity of the tire T can be measured.
By the way, when performing the tire test as described above, it is necessary to adjust the air pressure in the tire T to a predetermined air pressure. Therefore, the tire test apparatus 2 is provided with a pneumatic circuit 1 that adjusts the air pressure in the tire T by supplying compressed air into the tire T or discharging the compressed air from the tire T.
　図１に示されるように、空気圧回路１は、空気供給源１０からタイヤＴ内へ至る配管を備える。この配管は、上タイヤ軸４の内部を上下に貫通するように設けられた空気流路８の下側に開口した空気供給口９でタイヤＴ内に連通している。空気圧回路１は、空気流路８及び空気供給口９を通じて圧縮空気をタイヤＴ内に流通できるようになっている。
　図２に示されるように、空気圧回路１の基本構成は、空気供給源１０で発生された圧縮空気を所定の空気圧に調整してタイヤＴに供給することに向けられている。空気圧回路１は、タイヤＴに至る経路を２系統備えている。１つはタイヤＴを短時間で膨らましてタイヤＴのビードをリム６、７に押し付けるビードシート系統１１であり、もう１つがタイヤＴを試験する際に用いられるテスト系統１２である。 As shown in FIG. 1, the pneumatic circuit 1 includes a pipe extending from the air supply source 10 into the tire T. This pipe communicates with the inside of the tire T through an air supply port 9 opened to the lower side of the air flow path 8 provided so as to penetrate the inside of the upper tire shaft 4 vertically. The pneumatic circuit 1 can circulate compressed air into the tire T through the air flow path 8 and the air supply port 9.
As shown in FIG. 2, the basic configuration of the pneumatic circuit 1 is directed to adjusting the compressed air generated by the air supply source 10 to a predetermined air pressure and supplying it to the tire T. The pneumatic circuit 1 includes two routes to the tire T. One is a bead seat system 11 that inflates the tire T in a short time and presses the bead of the tire T against the rims 6 and 7, and the other is a test system 12 that is used when testing the tire T.
　なお、図２の空気圧回路１を説明するにあたっては、空気供給源１０側を上流側と、タイヤＴ側を下流側とする。
　ビードシート系統１１を介して流通される圧縮空気は、４００ｋＰａ程度の空気圧（ビード空気圧）に調整され、テスト系統１２を介して流通される圧縮空気は、ビードシート系統１１より低い２００ｋＰａ程度の空気圧（テスト空気圧）に調整されている。これらのビードシート系統１１及びテスト系統１２は、空気供給源１０からタイヤＴに至る途中で分岐し、それぞれの空気圧に調整された後、再び１つの配管に合流する。 In the description of the pneumatic circuit 1 of FIG. 2, the air supply source 10 side is the upstream side and the tire T side is the downstream side.
The compressed air circulated through the bead sheet system 11 is adjusted to an air pressure (bead air pressure) of about 400 kPa, and the compressed air circulated through the test system 12 is about 200 kPa lower than the bead sheet system 11 ( The test air pressure is adjusted. The bead seat system 11 and the test system 12 branch on the way from the air supply source 10 to the tire T, are adjusted to their respective air pressures, and then merge into one pipe again.
　次に、本実施形態を示すテスト系統１２とビードシート系統１１とについて図３を用いて詳しく説明する。
　図３に示されるように、空気圧回路１を空気供給源１０側（上流側）からタイヤＴ側（下流側）に追って見ると、当該空気圧回路１は空気昇温機構２１の下流側で２系統に分岐している。一方の経路はビードシート系統１１の経路となり、他方の経路はテスト系統１２となっている。なお、空気供給源１０から下流側に向かって分岐するまでの経路は共通であり、ビードシート系統１１やテスト系統１２内の空気圧を調整する空気を送る。また、一度分岐したビードシート系統１１及びテスト系統１２は、切替弁１５を介して合流し、その下流側の経路は共通である。 Next, the test system 12 and the bead sheet system 11 showing this embodiment will be described in detail with reference to FIG.
As shown in FIG. 3, when the pneumatic circuit 1 is viewed from the air supply source 10 side (upstream side) to the tire T side (downstream side), the pneumatic circuit 1 has two systems on the downstream side of the air temperature raising mechanism 21. It is branched to. One path is a bead sheet system 11 and the other path is a test system 12. In addition, the path | route until it branches toward the downstream side from the air supply source 10 is common, and the air which adjusts the air pressure in the bead seat system | strain 11 or the test system | strain 12 is sent. Further, the bead sheet system 11 and the test system 12 once branched join together via the switching valve 15, and the downstream path is common.
　テスト系統１２には、上流側から下流側に向かって順番に、圧力調整弁１３、給排弁１４、切替弁１５、遮断弁１６、圧力検知部１７が設けられている。ビードシート系統１１には、ビード圧調整弁２２、切替弁１５、遮断弁１６、圧力検知部１７が設けられている。遮断弁１６及び圧力検知部１７は、テスト系統１２及びビードシート系統１１に共通して設けられている。 The test system 12 is provided with a pressure regulating valve 13, a supply / discharge valve 14, a switching valve 15, a shutoff valve 16, and a pressure detection unit 17 in order from the upstream side to the downstream side. The bead seat system 11 is provided with a bead pressure adjusting valve 22, a switching valve 15, a shutoff valve 16, and a pressure detection unit 17. The shutoff valve 16 and the pressure detection unit 17 are provided in common for the test system 12 and the bead seat system 11.
　空気供給源１０は、図示されないコンプレッサなどで加圧された工場エアの供給源である。空気供給源１０は、ビードシート系統１１を通じてタイヤＴを膨らませる際の空気圧（ビード空気圧）と同等か、又はビード空気圧より高圧の圧縮空気を発生させている。空気供給源１０の下流側には、空気供給源１０から流入するダストなどを捕集するエアフィルタ１８が設けられている。また、エアフィルタ１８の下流側には、空気供給源１０で発生される圧縮空気の圧力をチェックする圧力計１９が設けられている。 The air supply source 10 is a supply source of factory air pressurized by a compressor (not shown). The air supply source 10 generates compressed air that is equal to or higher in pressure than the air pressure (bead air pressure) when the tire T is inflated through the bead seat system 11. An air filter 18 that collects dust and the like flowing from the air supply source 10 is provided on the downstream side of the air supply source 10. A pressure gauge 19 for checking the pressure of compressed air generated by the air supply source 10 is provided on the downstream side of the air filter 18.
　圧力調整弁（テスト圧調整弁）１３は、テスト系統１２内の圧縮空気を所定の圧力に調整するためのものであり、圧力レギュレータで構成されている。また、ビードシート系統１１の配管には、テスト圧調整弁１３と同様な構成を備えたビード圧調整弁２２が設けられている。
　空気供給源１０で発生した高圧の圧縮空気は、ビード圧調整弁２２によってビード空気圧（例えば４００ｋＰａ）に減圧される。 The pressure adjustment valve (test pressure adjustment valve) 13 is for adjusting the compressed air in the test system 12 to a predetermined pressure, and is composed of a pressure regulator. Further, a bead pressure adjusting valve 22 having the same configuration as the test pressure adjusting valve 13 is provided in the pipe of the bead seat system 11.
The high-pressure compressed air generated by the air supply source 10 is reduced to bead air pressure (for example, 400 kPa) by the bead pressure adjusting valve 22.
　切替弁１５は、圧縮空気の流路をテスト系統１２側とビードシート系統１１側とで切り替えて、タイヤＴ内の空気圧をビード空気圧とテスト空気圧とで切り替える。
　本実施形態の切替弁１５が作動する（オン状態である）ときには、ビードシート系統１１の配管からタイヤＴ内にビード空気圧に圧力調整された圧縮空気が供給される。切替弁１５が作動していない（オフ状態である）ときには、テスト系統１２の配管からテスト空気圧に圧力調整された圧縮空気がタイヤＴ内に供給される。 The switching valve 15 switches the flow path of the compressed air between the test system 12 side and the bead seat system 11 side, and switches the air pressure in the tire T between the bead air pressure and the test air pressure.
When the switching valve 15 of this embodiment operates (is in an ON state), compressed air whose pressure is adjusted to bead air pressure is supplied into the tire T from the pipe of the bead seat system 11. When the switching valve 15 is not operated (is in an off state), compressed air whose pressure is adjusted to the test air pressure is supplied into the tire T from the pipe of the test system 12.
　遮断弁１６は、切替弁１５の下流側に設けられた方向制御弁である。圧縮空気の流路は遮断弁１６を切り替えることで遮断され、遮断弁１６の下流側のタイヤＴ内へ至る配管内に圧縮空気を封じ込めることができる。
　給排弁１４は、テスト圧調整弁１３の下流側に設けられた方向制御弁である。給排弁１４の切替により、タイヤＴへの給気とタイヤＴからの排気（大気への放出）とが切り替えられる。 The shutoff valve 16 is a directional control valve provided on the downstream side of the switching valve 15. The flow path of the compressed air is shut off by switching the shutoff valve 16, and the compressed air can be contained in the pipe that reaches the tire T on the downstream side of the shutoff valve 16.
The supply / discharge valve 14 is a direction control valve provided on the downstream side of the test pressure adjustment valve 13. By switching the supply / exhaust valve 14, supply to the tire T and exhaust from the tire T (release to the atmosphere) are switched.
　また、圧力検知部１７として、給排弁１４の下流側に空気圧センサが設けられている。
　ところで、タイヤＴ内に作用させる空気圧を、テスト圧調整弁１３によりテスト空気圧に調整しても、タイヤ試験中にタイヤＴ内の空気圧が微小に変化してしまうことがある。このような空気圧の微小な変化は０．５ｋＰａ～１ｋＰａと小さいものであるため、圧力調整精度が±０．１％（例えば、１０００ｋＰａを定格とする圧力レギュレータの場合の調整制度は±１ｋＰａ程度）しかないテスト圧調整弁１３による調整は困難である。 Further, an air pressure sensor is provided as the pressure detection unit 17 on the downstream side of the supply / discharge valve 14.
By the way, even if the air pressure applied in the tire T is adjusted to the test air pressure by the test pressure adjusting valve 13, the air pressure in the tire T may slightly change during the tire test. Since such a small change in air pressure is as small as 0.5 kPa to 1 kPa, the pressure adjustment accuracy is ± 0.1% (for example, the adjustment system in the case of a pressure regulator rated at 1000 kPa is about ± 1 kPa) Adjustment using only the test pressure adjusting valve 13 is difficult.
　そこで、本発明のタイヤ試験装置２では、空気供給源１０からビード空気圧でタイヤに供給される空気が、空気昇温機構２１によって予め加熱される。そして、外気温度を上回る温度になった空気をタイヤに送ることにより、タイヤ試験中に生じる空気圧の変動が抑えられる。
　次に、本実施形態の空気昇温機構２１を詳しく説明する。 Therefore, in the tire test apparatus 2 of the present invention, the air supplied from the air supply source 10 to the tire with the bead air pressure is preheated by the air temperature raising mechanism 21. And the fluctuation | variation of the air pressure which arises during a tire test is suppressed by sending the air which became the temperature which exceeds outdoor temperature to a tire.
Next, the air temperature raising mechanism 21 of this embodiment will be described in detail.
　図３に示されるように、本実施形態の空気昇温機構２１は、空気供給源１０（圧力計１９）の下流側に設けられており、ビードシート系統１１とテスト系統１２との分岐点の上流側の配管に設けられている。この空気昇温機構２１は、空気供給源１０の下流側に配置されたタンク２３と、タンク２３内に設けられた熱交換器３０と、を有する。熱交換器３０は、熱媒をチューブに通して熱交換する等の構成を有している。 As shown in FIG. 3, the air temperature raising mechanism 21 of the present embodiment is provided on the downstream side of the air supply source 10 (pressure gauge 19), and is a branch point between the bead seat system 11 and the test system 12. It is provided in the upstream piping. The air temperature raising mechanism 21 includes a tank 23 disposed on the downstream side of the air supply source 10 and a heat exchanger 30 provided in the tank 23. The heat exchanger 30 has a configuration in which a heat medium is passed through a tube to exchange heat.
　次に、ビード空気圧でタイヤＴに供給される空気の温度を、外気温度を上回る温度へと上昇させることによって、タイヤ試験中にタイヤＴ内の空気圧が変化することを抑えられる点について、詳しく説明する。
　空気を供給して膨らませる前（つまり、膨張前且つリム６、７への装着前）のタイヤＴの空気の圧力及び配管内（以後タイヤＴ内に含める）の空気の圧力をＰ１（大気圧）、温度をＴ１（常温）とする。また、空気供給源１０から供給される空気の圧力をＰａ（ビード空気圧）、温度をＴａとする。 Next, it will be described in detail that the air pressure in the tire T can be prevented from changing during the tire test by raising the temperature of the air supplied to the tire T by the bead air pressure to a temperature exceeding the outside air temperature. To do.
P1 (atmospheric pressure) is the pressure of the air in the tire T and the pressure in the pipe (hereinafter included in the tire T) before inflating by supplying air (that is, before inflating and before mounting on the rims 6 and 7). ), The temperature is T1 (room temperature). The pressure of the air supplied from the air supply source 10 is Pa (bead air pressure), and the temperature is Ta.
　この場合において、空気供給源１０からビードシート系統１１に圧縮空気を供給してタイヤＴ内の圧力がビード空気圧Ｐａまで上昇した時の、膨張後のタイヤＴ内の空気の温度Ｔ２を算出する。
　タイヤＴ内の空気の質量をｍとし、空気の膨張時に外部から出入りする熱を０として断熱過程を考えると、エネルギの釣合は式（１）で表される。 In this case, the temperature T2 of the air in the tire T after expansion when the compressed air is supplied from the air supply source 10 to the bead seat system 11 and the pressure in the tire T rises to the bead air pressure Pa is calculated.
Considering the heat insulation process where m is the mass of air in the tire T and 0 is heat entering and exiting from the outside when the air expands, the energy balance is expressed by equation (1).
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　式（１）において、ｍ１は膨張前の空気質量、ｍ２は膨張後の空気質量、ｕ１は膨張前の比エネルギ、ｕ２は膨張後の比エネルギである。（ｍ２－ｍ１）は流入する空気質量、ｈは流入する空気の比エンタルピを示す。
　ここで、タイヤＴ内の比エネルギをｕ＝ＣｖＴ、タイヤＴ内に流入する空気の比エンタルピｈ＝ＣｐＴ（Ｃｖ：定積比熱定数、Ｃｐ：定圧比熱定数）とおくと、式（１）は、式（２）のように表される。 In equation (1), m1 is the air mass before expansion, m2 is the air mass after expansion, u1 is the specific energy before expansion, and u2 is the specific energy after expansion. (M2-m1) represents the mass of air flowing in, and h represents the specific enthalpy of the air flowing in.
Here, when the specific energy in the tire T is u = CvT and the specific enthalpy h = CpT of the air flowing into the tire T (Cv: constant volume specific heat constant, Cp: constant pressure specific heat constant), Equation (1) is , Expressed as equation (2).
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　状態方程式（ｍ＝ＰＶ／（ＲＴ）、Ｒ：気体定数、Ｖ：体積）及び比熱比γ（＝Ｃｐ／Ｃｖ）を用いると、式（２）から、式（３）が得られる。 Using the equation of state (m = PV / (RT), R: gas constant, V: volume) and specific heat ratio γ (= Cp / Cv), equation (3) is obtained from equation (2).
Figure JPOXMLDOC01-appb-M000003
Figure JPOXMLDOC01-appb-M000003
　なお、式（３）において、タイヤＴ内の空気の膨張後の圧力Ｐ２は、空気供給源１０から供給される空気の圧力Ｐａと同圧になるため、Ｐ２＝Ｐａである。
　式（３）をＴ２について整理すると、式（４）が得られる。 In Formula (3), since the pressure P2 after the expansion of the air in the tire T is the same as the pressure Pa of the air supplied from the air supply source 10, P2 = Pa.
Rearranging equation (3) with respect to T2, equation (4) is obtained.
Figure JPOXMLDOC01-appb-M000004
Figure JPOXMLDOC01-appb-M000004
　ここで、空気供給源１０から供給される空気の圧力を４００ｋＰａ（ゲージ圧）、空気の温度を室温（外気温度）の２０℃とする。また、タイヤＴ内の膨張前の空気を大気圧、２０℃（外気温度）とする。
　また、Ｐ１＝１００ｋＰａ（絶対圧）、Ｔ１＝２９３Ｋ（絶対温度）、Ｐａ＝Ｐ２＝５００ｋＰａ（絶対圧）、Ｔａ＝２９３Ｋ（絶対温度）、γ＝１．４とすると、式（４）から、ビードシート時のタイヤＴ内の温度Ｔ２は、１０７℃まで上昇することになる。 Here, the pressure of the air supplied from the air supply source 10 is 400 kPa (gauge pressure), and the temperature of the air is 20 ° C., which is room temperature (outside air temperature). Further, the air before expansion in the tire T is set to atmospheric pressure and 20 ° C. (outside air temperature).
When P1 = 100 kPa (absolute pressure), T1 = 293K (absolute temperature), Pa = P2 = 500 kPa (absolute pressure), Ta = 293K (absolute temperature), and γ = 1.4, The temperature T2 in the tire T at the time of the bead sheet rises to 107 ° C.
　次に、タイヤＴ内の空気の圧力がビード空気圧からテスト空気圧になるように、切替弁１５を切り替える。ここで、切替弁１５を切り替えるまでの間、即ち、タイヤＴ内の空気の圧力がビード空気圧になるようビード空気圧を保持している間は、タイヤＴ内の空気の熱がリム６、７やタイヤＴに伝達されることにより、タイヤＴ内の空気の温度が低下する。タイヤＴ内の空気の温度の低下量は、リム６、７やタイヤＴの温度とタイヤＴ内の空気の温度との間の差が大きい程、またビード空気圧を保持している時間が長いほど大きい。上述したようにタイヤＴ内の圧力をビード空気圧にした直後は、タイヤＴ内の空気の温度が非常に高い。したがって、ビード空気圧を保持する時間が僅かでもタイヤＴ内の空気の温度が５０℃程度低下する場合がある。この実施形態では、切替弁１５を切り替えたときのタイヤＴ内の空気の温度は５７℃であった。 Next, the switching valve 15 is switched so that the air pressure in the tire T changes from the bead air pressure to the test air pressure. Here, until the switching valve 15 is switched, that is, while the bead air pressure is maintained so that the air pressure in the tire T becomes the bead air pressure, the heat of the air in the tire T By being transmitted to the tire T, the temperature of the air in the tire T decreases. The amount of decrease in the temperature of the air in the tire T is such that the larger the difference between the temperature of the rims 6 and 7 and the tire T and the temperature of the air in the tire T, and the longer the time during which the bead air pressure is maintained. large. As described above, immediately after the pressure in the tire T is set to bead air pressure, the temperature of the air in the tire T is very high. Therefore, the temperature of the air in the tire T may decrease by about 50 ° C. even if the time for holding the bead air pressure is short. In this embodiment, the temperature of the air in the tire T when the switching valve 15 is switched was 57 ° C.
　次に、タイヤＴ内がビード空気圧からテスト空気圧に移行する時、即ち、切替弁１５を切り替えたときは、タイヤＴから急激に空気が抜けるために断熱膨張により温度は低下する。
　ここで、ビード空気圧時のタイヤＴ内の空気の圧力及び温度をＰ１及びＴ１、テスト空気圧の時のタイヤＴ内の空気の圧力及び温度をＰ２及びＴ２とすると、断熱膨張前後の圧力と温度の関係は、比熱比γを用いて式（５）で表される。 Next, when the inside of the tire T shifts from the bead air pressure to the test air pressure, that is, when the switching valve 15 is switched, the temperature is lowered due to adiabatic expansion because air suddenly escapes from the tire T.
Here, if the pressure and temperature of the air in the tire T at the bead air pressure are P1 and T1, and the pressure and temperature of the air in the tire T at the test air pressure are P2 and T2, the pressure and temperature before and after adiabatic expansion are The relationship is expressed by equation (5) using the specific heat ratio γ.
Figure JPOXMLDOC01-appb-M000005
Figure JPOXMLDOC01-appb-M000005
　ビード空気圧Ｐ１を５００ｋＰａ（絶対圧）、テスト空気圧Ｐ２を３００ｋＰａ（絶対圧）とすると、テスト圧での絶対温度Ｔ２は、Ｔ１の８６％となる。よって、ビード空気圧時（切換弁１５の切り替え時）のタイヤＴ内温度が５７℃（３３０Ｋ）であれば、テスト空気圧になった時にタイヤＴ内の空気の温度は１１℃となる。
　このテスト空気圧時のタイヤＴ内の空気の温度は１１℃であり、外気温度２０℃よりも低い状態にある。このように、タイヤＴ内の空気の温度が外気温度よりも低い状態でタイヤ試験を行うと、常温のタイヤＴのゴムや金属製のリム６、７の熱がタイヤＴ内に伝わり、タイヤ試験中にタイヤＴの空気の温度が上昇してしまう。タイヤ試験中にタイヤＴ内の空気の温度が上昇すると、タイヤＴ内の空気の圧力が変化し、タイヤＴ内の空気の圧力が上昇してしまう。なお、タイヤＴ内の空気とタイヤＴ及びリム６、７との間の温度差が大きいほど伝熱量は大きく、熱容量の小さいタイヤＴ内の空気の温度はどんどん上昇し、それに応じてタイヤＴ内の圧力が上昇していく。 When the bead air pressure P1 is 500 kPa (absolute pressure) and the test air pressure P2 is 300 kPa (absolute pressure), the absolute temperature T2 at the test pressure is 86% of T1. Therefore, if the temperature in the tire T at the time of bead air pressure (when the switching valve 15 is switched) is 57 ° C. (330 K), the temperature of the air in the tire T becomes 11 ° C. when the test air pressure is reached.
The temperature of the air in the tire T at this test air pressure is 11 ° C., which is lower than the outside air temperature 20 ° C. As described above, when the tire test is performed in a state where the temperature of the air in the tire T is lower than the outside air temperature, the heat of the rubber T and the metal rims 6 and 7 of the normal temperature tire T is transmitted into the tire T, and the tire test is performed. The air temperature of the tire T rises inside. If the temperature of the air in the tire T rises during the tire test, the pressure of the air in the tire T changes, and the pressure of the air in the tire T increases. As the temperature difference between the air in the tire T and the tire T and the rims 6 and 7 increases, the amount of heat transfer increases, and the temperature of the air in the tire T having a small heat capacity increases steadily. The pressure increases.
　そこで、本発明のタイヤ試験装置２では、空気供給源１０からビード空気圧でタイヤＴに供給される空気として、空気昇温機構２１によって外気温度を上回るように温度を上昇させた空気を配管系統に流し込むことを特徴とするものである。
　空気供給源１０からタイヤＴ内にビード空気圧（ゲージ圧で４００ｋＰａ）で供給する空気は、タンク２３内にて熱交換器３０によって昇温される。タンク２３内の空気の温度を外気温度（常温）よりも１０℃高くすると、上述したようにビード空気圧時（切換弁１５の切り替え時）のタイヤＴ内の空気の温度は６７℃となる。この後、タイヤＴ内の空気の圧力を、ビード空気圧から、テスト空気圧の２００ｋＰａ（ゲージ圧）まで下げると、タイヤＴ内の空気の温度は１９．４℃となり、外気温度とほぼ等しくなる。この場合、タイヤ試験時における温度変化は僅かであり、圧力変化はほとんど発生しない。 Therefore, in the tire test apparatus 2 of the present invention, air whose temperature is increased by the air temperature raising mechanism 21 so as to exceed the outside air temperature is supplied to the piping system as the air supplied from the air supply source 10 to the tire T by the bead air pressure. It is characterized by pouring.
The air supplied from the air supply source 10 into the tire T at the bead air pressure (gauge pressure of 400 kPa) is heated by the heat exchanger 30 in the tank 23. When the temperature of the air in the tank 23 is increased by 10 ° C. from the outside air temperature (normal temperature), as described above, the temperature of the air in the tire T at the bead air pressure (when the switching valve 15 is switched) becomes 67 ° C. Thereafter, when the pressure of the air in the tire T is lowered from the bead air pressure to the test air pressure of 200 kPa (gauge pressure), the temperature of the air in the tire T becomes 19.4 ° C., which is substantially equal to the outside air temperature. In this case, the temperature change during the tire test is slight, and the pressure change hardly occurs.
　実際には、タイヤＴ内の最終温度は、上記の計算により求められる温度変化以外に、伝熱による温度変化の影響を受ける。冷却された空気の温度設定は、各タイヤ試験装置２において、適切な値を実験的に調べることが望ましい。また、ビード空気圧からテスト空気圧に移行した際にタイヤＴ内の温度が外気温度の±５℃の範囲内であれば、温度変化及び圧力変化が緩やかであることが、実験により確認されている。 Actually, the final temperature in the tire T is affected by the temperature change due to heat transfer in addition to the temperature change obtained by the above calculation. It is desirable that the temperature setting of the cooled air is experimentally examined for an appropriate value in each tire testing device 2. Further, it has been experimentally confirmed that the temperature change and the pressure change are moderate if the temperature in the tire T is within a range of ± 5 ° C. of the outside air temperature when the bead air pressure is changed to the test air pressure.
　上述の空気圧回路１を備えたタイヤ試験装置２によれば、以下の手順でタイヤ試験が行われる。
　すなわち、タイヤ試験を行う際は、まずビードシート系統１１の配管を介してタイヤＴ内の空気圧をビード空気圧に調整し、熱交換器３０によって外気温度を上回る温度まで加熱した空気（例えば、３０℃、外気温度よりも＋１０℃）を供給して、タイヤＴを短時間で膨張させ、タイヤＴのビード部をリム６、７に強固に装着する。 According to the tire test apparatus 2 provided with the pneumatic circuit 1 described above, the tire test is performed in the following procedure.
That is, when performing a tire test, first, the air pressure in the tire T is adjusted to the bead air pressure via the pipe of the bead seat system 11, and air heated to a temperature exceeding the outside air temperature by the heat exchanger 30 (for example, 30 ° C. The tire T is inflated in a short time, and the bead portion of the tire T is firmly attached to the rims 6 and 7.
　タイヤＴの装着時には、切替弁１５をオン状態、遮断弁１６をオフ状態とすることにより、テスト系統１２の空気流路が閉鎖されると共にビードシート系統１１の空気流路が開通される。そして、ビードシート系統１１側の経路を介して圧縮空気をタイヤＴに流通させることにより、タイヤＴが膨張する。ビード空気圧でタイヤＴを膨張させた直後のタイヤＴ内の温度は、１１７℃となる。
　次に、給排弁１４をオン状態、遮断弁１６をオフ状態にしたまま、切替弁１５をオフ状態とする。このようにして圧縮空気の流路をテスト系統１２に切り替えると共に、タイヤＴ内の空気を空気流路８外に排気する。また、テスト系統１２の配管にはテスト圧調整弁１３が設けられており、ビード空気圧にされていたタイヤＴ内の圧縮空気の圧力を、テスト空気圧へと切り替える。ビード空気圧からテスト空気圧に切り替える間は、タイヤＴの空気の熱がタイヤＴやリム６、７に伝達されるため、当該空気の温度は次第に下がる。テスト空気圧に切り替えた直後のタイヤＴ内の空気の温度は、６７℃となる。 When the tire T is mounted, the switching valve 15 is turned on and the shutoff valve 16 is turned off, whereby the air flow path of the test system 12 is closed and the air flow path of the bead seat system 11 is opened. And the tire T expand | swells by distribute | circulating compressed air to the tire T via the path | route by the side of the bead seat system | strain 11 side. The temperature in the tire T immediately after the tire T is expanded with the bead air pressure is 117 ° C.
Next, the switching valve 15 is turned off while the supply / discharge valve 14 is on and the shutoff valve 16 is off. In this way, the flow path of the compressed air is switched to the test system 12 and the air in the tire T is exhausted outside the air flow path 8. Further, a test pressure adjusting valve 13 is provided in the piping of the test system 12, and the pressure of the compressed air in the tire T, which has been set to bead air pressure, is switched to the test air pressure. While the bead air pressure is switched to the test air pressure, the heat of the air of the tire T is transmitted to the tire T and the rims 6 and 7, so that the temperature of the air gradually decreases. The temperature of the air in the tire T immediately after switching to the test air pressure is 67 ° C.
　そして、タイヤＴ内の空気の圧力をテスト空気圧にすると、当該タイヤＴ内の空気は断熱膨張するため、テスト空気圧下でのタイヤＴ内の空気の温度は、ほぼ外気温度まで下がる（例えば、テスト空気圧下で１９．４℃）。
　このように、外気温度よりも１０℃程度高温の空気をタイヤＴに供給しておけば、ビード空気圧からテスト空気圧に切り替える間にタイヤＴ内の空気の温度が低下したとしても、ビード空気圧からテスト空気圧まで降圧したとき、即ち、タイヤ試験直後のタイヤＴ内の空気の温度を略外気温度とすることができる。その結果、タイヤ試験中（タイヤ試験は、１秒程度で行われる）の温度変化は僅かとなり、式（５）により、圧力変化はほとんど発生しないこととなる。 When the pressure of the air in the tire T is changed to the test air pressure, the air in the tire T is adiabatically expanded, so that the temperature of the air in the tire T under the test air pressure is almost lowered to the outside air temperature (for example, test (19.4 ° C. under air pressure).
In this way, if air having a temperature about 10 ° C. higher than the outside air temperature is supplied to the tire T, even if the temperature of the air in the tire T decreases while switching from the bead air pressure to the test air pressure, the test is performed from the bead air pressure. When the pressure is reduced to the air pressure, that is, the temperature of the air in the tire T immediately after the tire test can be made substantially the outside air temperature. As a result, the temperature change during the tire test (the tire test is performed in about 1 second) becomes slight, and the pressure change hardly occurs according to the equation (5).
　つまり、空気供給源１０からタイヤＴに供給される空気を加熱して当該空気の温度を外気温度よりも高くする空気昇温機構２１を設けることにより、圧力レギュレータでは調整することが困難な空気圧の変動を抑制することができる。それゆえ、タイヤ試験中にタイヤＴをテスト空気圧に維持することが可能となり、ユニフォーミティを精度良く計測することが可能となる。 In other words, by providing the air temperature raising mechanism 21 that heats the air supplied from the air supply source 10 to the tire T and makes the temperature of the air higher than the outside air temperature, the air pressure that is difficult to adjust with the pressure regulator is obtained. Variations can be suppressed. Therefore, the tire T can be maintained at the test air pressure during the tire test, and the uniformity can be accurately measured.
　本発明は上記各実施形態に限定されるものではなく、発明の本質を変更しない範囲で各部材の形状、構造、材質、組み合わせなどを適宜変更可能である。
　上記実施形態では、タイヤ試験装置２として、ユニフォーミティマシンが例に挙げられている。しかし、本発明の空気圧回路１は、ユニフォーミティ以外の評価を行うタイヤ試験装置に用いることもできる。実施形態の空気昇温機構２１は、熱交換器３０によって空気を加熱することによりタイヤＴに供給する空気の温度を外気温度よりも高くしていたが、代わりに、ビード空気を供給する前にタンク２３内の空気を断熱圧縮することにより空気の温度を上昇させてもよい。 The present invention is not limited to the above-described embodiments, and the shape, structure, material, combination, and the like of each member can be appropriately changed without changing the essence of the invention.
In the above embodiment, a uniformity machine is cited as an example of the tire testing apparatus 2. However, the pneumatic circuit 1 of the present invention can also be used in a tire testing apparatus that performs evaluations other than uniformity. Although the air temperature raising mechanism 21 of the embodiment heated the air by the heat exchanger 30 and made the temperature of the air supplied to the tire T higher than the outside air temperature, instead, before supplying the bead air, The temperature of the air may be raised by adiabatically compressing the air in the tank 23.
　本出願は２００９年１２月１４日出願の日本特許出願（特願２００９－２８２７９７）に基づくものであり、その内容はここに参照として取り込まれる。 This application is based on a Japanese patent application filed on December 14, 2009 (Japanese Patent Application No. 2009-282797), the contents of which are incorporated herein by reference.
　１　空気圧回路
　２　タイヤ試験装置
　３　フレーム
　４　上タイヤ軸
　５　下タイヤ軸
　６　上リム
　７　下リム
　８　空気流路
　９　空気供給口
　１０　空気供給源
　１１　ビードシート系統
　１２　テスト系統
　１３　圧力調整弁（テスト圧調整弁）
　１４　給排弁
　１５　切替弁
　１６　遮断弁
　１７　圧力検知部
　１８　エアフィルタ
　１９　圧力計
　２１　空気昇温機構
　２２　ビード圧調整弁
　２３　タンク
　３０　熱交換器
　Ｔ　タイヤ DESCRIPTION OF SYMBOLS 1 Pneumatic circuit 2 Tire test apparatus 3 Frame 4 Upper tire shaft 5 Lower tire shaft 6 Upper rim 7 Lower rim 8 Air flow path 9 Air supply port 10 Air supply source 11 Bead seat system 12 Test system 13 Pressure adjustment valve (Test pressure adjustment valve)
DESCRIPTION OF SYMBOLS 14 Supply / Drain valve 15 Switching valve 16 Shut-off valve 17 Pressure detection part 18 Air filter 19 Pressure gauge 21 Air temperature rising mechanism 22 Bead pressure adjustment valve 23 Tank 30 Heat exchanger T Tire

Claims (5)

  1. 　一対のリム間に装着されるタイヤに空気を供給する空気供給源を備えるタイヤ試験装置の空気圧回路であって、
    　前記空気供給源からタイヤに供給される空気の温度を外気温度よりも高くする空気昇温機構を備えることを特徴とするタイヤ試験装置の空気圧回路。     A pneumatic circuit of a tire testing apparatus including an air supply source for supplying air to a tire mounted between a pair of rims,
    A pneumatic circuit for a tire testing apparatus, comprising an air temperature raising mechanism for raising a temperature of air supplied from the air supply source to the tire to be higher than an outside air temperature.
  2. 　前記空気供給源からタイヤに供給される空気の圧力を、前記タイヤを膨らませてリムに装着するためのビード空気圧又はこのビード空気圧より低圧なタイヤ試験時に用いるテスト空気圧に調整する圧力調整弁を備え、
    　前記空気昇温機構は、前記ビード空気圧でタイヤに供給される空気の温度が外気温度よりも高くなるように、当該空気を加熱するように構成されていることを特徴とする請求項１に記載のタイヤ試験装置の空気圧回路。     A pressure adjusting valve that adjusts the pressure of the air supplied to the tire from the air supply source to a bead air pressure for inflating the tire to be attached to a rim or a test air pressure used in a tire test lower than the bead air pressure;
    The said air temperature rising mechanism is comprised so that the said air may be heated so that the temperature of the air supplied to a tire with the bead air pressure may become higher than external temperature. Pneumatic circuit for tire testing equipment.
  3. 　前記空気昇温機構は、前記空気供給源からの空気を貯蔵可能なタンクと、このタンク内の空気を加熱する熱交換器と、を有することを特徴とする請求項１に記載のタイヤ試験装置の空気圧回路。 The tire test apparatus according to claim 1, wherein the air temperature raising mechanism includes a tank capable of storing air from the air supply source and a heat exchanger for heating the air in the tank. Pneumatic circuit.
  4. 　請求項１～３のいずれか１項に記載の空気圧回路を備えることを特徴とするタイヤ試験装置。 A tire testing apparatus comprising the pneumatic circuit according to any one of claims 1 to 3.
  5. 　ビード空気圧に調整された空気をタイヤに供給することにより前記タイヤを膨らませて一対のリム間に装着する工程と、
    　前記リム間に装着された前記タイヤに前記ビード空気圧より低圧なテスト空気圧に調整された空気を供給した状態で前記タイヤの特性を計測する工程と、を有するタイヤ試験方法であって、
    　外気温度よりも温度を高くした空気を、前記ビード空気圧で前記タイヤに供給することを特徴とするタイヤ試験方法。     A step of inflating the tire by supplying air adjusted to bead air pressure to the tire and mounting between the pair of rims;
    Measuring the characteristics of the tire in a state where air adjusted to a test air pressure lower than the bead air pressure is supplied to the tire mounted between the rims, and a tire test method comprising:
    A tire test method, wherein air having a temperature higher than an outside air temperature is supplied to the tire at the bead air pressure.
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Publication number Priority date Publication date Assignee Title
JP2013178214A (en) * 2012-02-29 2013-09-09 Sumitomo Rubber Ind Ltd Tire testing method

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