JP2009029180A - Tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bead acceleration test device capable of performing a test for promptly reproducing a failure of the bead, and raising a temperature of the bead under given conditions. <P>SOLUTION: The heating device 10 for the bead acceleration test is disposed on the bead seat surface 13 of a rim 12 for mounting a tire 11, and equipped with a heater 1 which contacts with the bead of the rotating tire 11 mounted to the rim 12 and to heat the bead. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heating device used for a bead portion acceleration test performed indoors.

  In order to speed up the evaluation of tires in failure analysis and new development work, indoor acceleration tests that can reproduce failures that occur in actual vehicle driving at an early stage are widely performed. Therefore, the test conditions of the indoor acceleration test are more severe than the actual vehicle, such as ambient temperature, load load, speed, etc., and the failure occurrence probability during actual vehicle travel is estimated from the test results, and is associated with the actual vehicle travel condition. Thus, a test method capable of controlling the test conditions to be constant is adopted.

  Failure of bead parts, especially bead parts of heavy-duty vehicle tires and construction vehicle tires, is important for tires and must be suppressed. The current situation is that no test method to reproduce is found. In other words, it is known that if the temperature of the bead part is increased from that during normal driving, the probability of occurrence of the failure increases and the failure can be reproduced at an early stage. However, it has been difficult to control to satisfy certain conditions.

  The present invention has been made in view of such problems, and can perform a test for reproducing a failure of a bead part at an early stage, and further, the temperature of the bead part can be raised under a constant condition. An object of the present invention is to provide a bead part acceleration test apparatus.

  <1> is a heating device for a bead portion acceleration test, which is provided on a bead seat surface of a rim on which a tire is mounted, and includes a heater that contacts and heats the bead portion of the tire mounted on the rim and rotates. It is.

  <2> is a bead unit acceleration according to <1>, wherein a temperature sensor is attached to the surface of the bead sheet, and the control unit controls the amount of heat generated by the heater so that the temperature detected by the temperature sensor becomes a predetermined value. This is a test heating device.

  <3> is a heating device for a bead portion acceleration test in which the heater in <1> or <2> is composed of a film-like heating element and each film-like insulating layer sandwiching the heater from both sides.

  <4> is a heating device for bead part acceleration test, wherein a heat insulating layer having a lower thermal conductivity than the rim is disposed between the heater and the rim in any one of <1> to <3>. It is.

  <5> In any one of <1> to <4>, the power supply for the heater is installed in a non-rotating fixed system, and the power supply and the power supply are connected via a slip ring provided on a tire rotation axis. It is a heating device for a bead part acceleration test which makes an electric conduction with a heater.

  <6> is any one of <1> to <4>, wherein the control unit is installed in a stationary system that does not rotate, and the control unit and the temperature via a slip ring provided on a tire rotation axis. It is a heating device for a bead part acceleration test formed by electrically connecting a sensor.

  <7> is a heating device for a bead part acceleration test in any one of <1> to <6>, wherein the number of the heaters is plural and can be controlled independently of each other.

  According to <1>, the tire bead portion is provided on the bead seat surface of the rim on which the tire is mounted, and includes a heater that contacts and heats the bead portion of the tire that is mounted on the rim and rotates. When the entire tire is heated, the temperature of the bead portion varies, and the problem that the test result cannot be related to the failure occurrence rate in actual vehicle traveling can be solved. it can.

  According to <2>, the temperature sensor is attached to the bead sheet surface, and the controller includes a control unit that controls the amount of heat generated by the heater so that the temperature detected by the temperature sensor becomes a predetermined value. Further, the control can be performed with high accuracy, and even the test conditions in which the temperature conditions change with time can be easily realized by suppressing the occurrence of variations.

  According to <3>, since the heater is composed of a film-like heating element and the respective film-like insulating layers sandwiching the heater from both sides, the thickness of the heater can be extremely reduced. This can prevent the air seal on the bead seat surface from becoming incomplete and the air in the tire from being released.

  According to <4>, since the heat insulating layer is disposed between the heater and the rim, this can be realized with a small amount of heat with respect to the temperature of the same bead portion.

  According to <5>, the power supply for the heater is installed in a non-rotating fixed system, and the power supply and the heater are electrically connected via a slip ring provided on the tire rotation axis. If the power source is to be placed on a rotating tire or wheel, the power source such as a battery must be placed on the rotating tire or wheel, and the test cannot be performed due to an increase in weight or the like. .

  According to <6>, the control unit is installed in a non-rotating fixed system, and the control unit and the temperature sensor are electrically connected via a slip ring provided on the tire rotation axis. The control unit can be installed at a location away from the rotating body, and the temperature during the test can be monitored.

  According to <6>, since the number of the heaters is set to be plural and can be controlled independently of each other, the test can be continued even if a part of the apparatus breaks down.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an embodiment of a heating device for a bead part acceleration test in an attached state. The heater 1 constituting the heating apparatus for a bead part acceleration test 10 is a bead seat of a rim 12 on which a tire 11 is mounted. It arrange | positions on the surface 13 and is being fixed to the bead sheet | seat surface 13 by means, such as adhesion | attachment.

  2 and 3 are a plan view and a cross-sectional view, respectively, showing the heater 1. The heater 1 sandwiches the film-like heating element 2 that effectively generates heat by the power supplied from the power source 8 and both sides thereof. It is comprised with each film-like insulating layer 3a, 3b.

  Further, it is preferable to provide a heat insulating layer 4 having a thermal conductivity smaller than that of the rim 12 between the heater 1 and the rim 12, whereby heat generated in the heater 1 can be conducted intensively in the tire. In addition to increasing the heating efficiency, temperature variations can be reduced.

  As a material of the film-like heating element 2, for example, a stainless steel foil, nichrome wire, as a material of the film-like insulating layers 3a and 3b, a polyimide tape, a glass fiber tape, and a heat insulating layer 4 are used. Examples of the material include ceramic fiber and glass fiber, respectively. In order to increase the amount of heat generated within a small area, as shown in the drawing, it is necessary to lengthen the total length of the lines extending in series with the film-like heating element 2, for example, a U-shaped or zigzag film It is preferable to fold the continuous heating element 2 continuously.

  Also, the film-like heating element thickness should be 40-60 μm, and if it is less than 40 μm, it may cause a shortage of heat generation or cause disconnection during production, while this exceeds 60 μm. In such a case, the amount of heat generated becomes too large, and a gap between the wires must be made large, reducing the space efficiency and increasing the temperature variation of the bead sheet surface. Also, the thickness of the film-like insulating layers 3a and 3b should be 50 to 300 μm. If this is less than 50 μm, the insulation performance and strength will be insufficient, while the thickness exceeds 300 m. However, the material cost increases and the workability of the heater also deteriorates.

  When installing the heater 1, it is preferable to form a recess in the rim 12 that accommodates the heat insulating layer 4 without any gap, and to fit into the recess, so that the heater 1 can be fixed without being displaced, Furthermore, by applying lubricating oil to the exposed surface of the heater 1, damage to the heater 1 when the tire 11 is mounted on the rim 12 can be suppressed.

  In order to heat the bead portion of the tire with a predetermined temperature with high accuracy, the temperature sensor 5 for measuring the temperature of the surface of the bead portion and the temperature detected by the temperature sensor 5 are predetermined. Thus, it is preferable to provide a control unit 6 that adjusts the electric power applied to the heater 1. As the temperature sensor 5, a thermocouple, a resistance thermometer, or the like may be used. Moreover, if the display 7 which displays the temperature in measurement is provided, the temperature rising condition of a bead part can be checked visually.

  Since the rim 12 fitted with the tire 11 is attached to the tire rotating shaft 21 and rotates at a high speed during the test, it is preferable to attach a heavy component to a non-rotating fixed system unit so as not to affect the test performance. Therefore, the power supply 8, the control unit 6, the display 7 and the like are preferably provided in a fixed system.

  In this case, since electrical continuity is required between the rotating system and the fixed system, the slip ring 14 configured so that the fixed portion and the rotating portion are in electrical contact is arranged on the tire rotation axis as shown in the figure. The power supply 8 and the heater 1 are electrically connected via the slip ring 14, and the temperature sensor 5 and the controller 6 are electrically connected.

  Further, the path through the heater lead wire 15 connecting the heater 1 and the power source 8 and the temperature sensor lead wire 16 connecting the temperature sensor 5 and the control unit 6 is from the bead seat surface 13 to the center in the tire width direction. A first path (see FIG. 1) that passes through the rim 12 and then reaches the slip ring 14 after being directed, and, as shown in FIG. It is possible to take a second path that penetrates or reaches the slip ring 14 on the outer side in the width direction of the tire. When the first path is adopted, the lead wires 15 and 16 are arranged so that air in the tire internal pressure portion does not leak. It is necessary to hermetically seal the rim penetrating portion. Further, when the second path is adopted, it is preferable to use a combination type rim 12 and guide the lead wires 15 and 16 from the inner side to the outer side of the rim 12 through the combined portion of the combination.

  Further, when the lead wires 15 and 16 are passed through the rim 12, it is preferable to use shield metal fittings or metal fittings for fixing the lead wires 15 and 16 to the rim, so that the lead wires 15 and 16 rotate the rim 12. Can prevent play and play, and can prevent disconnection.

  As shown in FIG. 4, the circumferential arrangement on the rim 12 of the heater 1 can be limited to a part of the circumferential position, or as shown in FIG. It can also be arranged. In addition, it is preferable to increase the work efficiency by providing a plurality of heaters 1 and controlling them independently of each other.

The tire 11 was heated using the heater 1 shown in FIGS. 2 and 3, and the temperature rise effect was examined. The specifications of the heater used are as follows, and the results of the temperature rise test are shown in the graph of FIG.
Electrical specifications: 100V (rated), 195W (rated), 51.4Ω (± 10%)
Heat-resistant temperature: 180 ° C
Total thickness: 0.3mm (excluding temperature sensor and lead wire)
Each member 1) Film-like heating element: Stainless steel foil (thickness 50μm)
2) Film-like insulating layer: Polyimide thin film (heat resistant at 350 ° C)

  In FIG. 7, the horizontal axis indicates the scale of the control dial corresponding to the voltage applied to the heater, and the vertical axis indicates the surface temperature of the tire bead, that is, the temperature detected by the temperature sensor 5. The measurement point when both heaters are operated is a black circle, and if one heater is disconnected, the measurement point when only one heater is operated is a white circle. Expressed in As can be seen from FIG. 7, the temperature of the bead portion of the tire can be increased intensively, and the temperature can be controlled to be a desired value, which is reproducible.

  The present invention can be used for bead acceleration tests of various tires.

It is sectional drawing which shows the heating apparatus for bead part acceleration tests of embodiment which concerns on this invention in the attachment state. It is a top view which shows a heater. It is sectional drawing which shows a beater. It is a schematic diagram which shows the arrangement | positioning aspect of a heater. It is a schematic diagram which shows the other arrangement | positioning aspect of a heater. It is sectional drawing which shows the other aspect of the path | route of a lead wire. It is a graph which shows the temperature rising effect of a heater.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heater 3a, 3b Film-like insulation layer 4 Heat insulation layer 5 Temperature sensor 6 Control part 7 Display 8 Power supply 10 Bead part acceleration test heating device 11 Tire 12 Rim 13 Rim bead sheet surface 14 Slip ring 15 Heater lead wire 16 Temperature Sensor lead wire 21 Tire center axis

Claims (7)

  A heating device for a bead portion acceleration test, comprising a heater that is disposed on a bead seat surface of a rim on which a tire is mounted and that contacts and heats a bead portion of a tire that is mounted on a rim and rotates.   The bead unit acceleration test heating device according to claim 1, further comprising a control unit that attaches a temperature sensor to the bead sheet surface and controls a heating value of the heater so that a temperature detected by the temperature sensor becomes a predetermined value. .   The heating device for a bead part acceleration test according to claim 1 or 2, wherein the heater is constituted by a film-like heating element and respective film-like insulating layers sandwiching the heater from both sides. The heating device for a bead part acceleration test according to any one of claims 1 to 3, wherein a heat insulating layer having a lower thermal conductivity than the rim is disposed between the heater and the rim.   The power source for the heater is installed in a stationary system that does not rotate, and the power source and the heater are electrically connected via a slip ring provided on a tire rotation axis. The bead part acceleration test heating apparatus according to claim 1.   The control unit is installed on a fixed side that does not rotate, and the control unit and the temperature sensor are electrically connected to each other via a slip ring provided on a tire rotation shaft. Heating device for bead part acceleration test described in 1.   The heating device for a bead part acceleration test according to any one of claims 1 to 6, wherein the number of the heaters is plural, and they can be controlled independently of each other.

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