JP4178115B2 - Belt life detection system - Google Patents

Description

  The present invention relates to a system for predicting the life of a power transmission belt used in, for example, an automobile engine and informing a user or the like of a belt replacement time.

  The transmission belt is wound around the driving and driven pulleys, and transmits the driving force on the driving side to the driven side. A large load acts on the transmission belt when transmitting the driving force, and the canvas is worn by this load. When the wear of the canvas proceeds by a certain amount, for example, a toothed belt causes chipping and the like, and the driving force on the driving side cannot be properly transmitted to the driven side. Therefore, it is desirable to replace the transmission belt before the wear of the canvas proceeds by a certain amount.

  Therefore, conventionally, a method is known in which the degree of wear of the canvas is confirmed visually to determine the life of the transmission belt. However, when the degree of wear is visually confirmed, the judgment is left to the experience of the person who confirms it, and it is difficult to accurately grasp the degree of wear.

  Conventionally, there has been known a method for predicting the life of a belt by measuring the electrical resistance of a core formed of a conductive material and grasping the damaged state of the core (for example, Patent Document 1). According to this method, the end portion of the core wire is exposed on the side surface of the belt, and the electrical resistance between the exposed end portions is measured.

  However, in this method, in order to measure the electric resistance, the belt must be stopped each time, and the terminal of the measuring instrument must be attached to the end portion of the core wire. Therefore, it is difficult to apply this method, for example, when the belt is used in a complicated apparatus or when the belt must be rotated for a long time.

A transmission belt in which a conductive coating agent is applied to canvas is conventionally known (for example, Patent Document 2).
JP-A-9-242826 Japanese Patent Laid-Open No. Sho 62-185650

  Accordingly, the present invention is to solve the above problems, and an object of the present invention is to provide a belt life detection system capable of predicting the life even during belt rotation with a simple configuration.

  A belt life prediction system according to the present invention includes a power transmission belt having a contact surface with a pulley, which is formed by covering a pulley and forming a conductive layer having a higher conductivity than the inner layer on the outer side of the inner layer. Measuring means for measuring the electrical resistance between a part of the surface and the other part of the contact surface, and judgment for determining a decrease in the transmission performance with respect to the pulley of the transmission belt due to an increase in the electrical resistance due to wear of the contact surface And means. Thereby, the life of the transmission belt can be easily predicted.

  The transmission belt has a belt body, and the inner layer is preferably a canvas covering one surface of the belt body, and the canvas is an insulator.

  When the pulley has conductivity, the measuring means measures an electrical resistance between the pulley and a part of the contact surface at a position not in contact with the pulley. Further, when the transmission belt is wound around two pulleys having conductivity, the measuring means measures the electric resistance between the two pulleys. Thereby, an electrical resistance can be measured easily.

  The conductive layer is preferably formed of a material containing at least one of a rubber paste and an RFL composition and a conductive material. The conductive material preferably contains at least one of silver and graphite.

  The transmission belt according to the present invention is a transmission belt that is wound around a pulley and wears a contact surface with the pulley. The contact surface is formed by covering a conductive layer having a higher conductivity than the inner layer on the outside of the inner layer. A decrease in transmission performance with respect to the pulley can be determined by an increase in electrical resistance between a part of the contact surface due to wear of the contact surface and the other part of the contact surface.

  A belt life prediction method according to the present invention is a belt life prediction method for determining a reduction in transmission performance of a transmission belt caused by wear of a contact surface with a pulley that is wound around a pulley. A conductive layer having a conductivity higher than that of the inner layer is coated, and an electric resistance between a part of the contact surface and another part of the contact surface is measured. It is characterized by determining a decrease in transmission performance with respect to the pulley.

  According to the present invention, when the amount of wear of the transmission belt advances by a certain amount, the measured electrical resistance increases, so that it is possible to easily determine the decrease in the transmission performance of the transmission belt with respect to the pulley.

  FIG. 1 shows a toothed belt 10 according to an embodiment of the present invention. The toothed belt 10 is an endless belt and has a belt body 11. The belt body 11 is integrally formed by a tooth rubber layer 12 and a back rubber layer 13, and a core wire 19 is embedded in the boundary surface between the tooth rubber layer 12 and the back rubber layer 13. In the tooth rubber layer 12, tooth portions 14 and tooth bottom portions 15 are alternately and integrally formed along the longitudinal direction, and the outer surfaces of the tooth portions 14 and the tooth bottom portions 15 of the tooth rubber layer 12 are covered with a canvas 16.

  The outer surface of the canvas 16 is covered with a conductive layer 18. The conductive layer 18 is the outermost layer in the toothed belt 10, and the outer surface 17 of the conductive layer 18 is in contact with these pulleys when the toothed belt 10 is wound around pulleys 20, 21 (see FIG. 2). It becomes the contact surface.

  The canvas 16 is a fabric woven by wefts and warps such as synthetic fibers and natural fibers, and is substantially an insulator. Therefore, the electrical resistance value between the predetermined distances of the canvas 16 (for example, 20 cm in the belt longitudinal direction) is very large (for example, 2 MΩ or more), preferably infinite. The synthetic fiber and natural fiber are, for example, aramid, nylon, or cotton.

  The conductive layer 18 has conductivity, and its conductivity is very high compared to the conductivity of the canvas 16. Therefore, the electrical resistance value between the predetermined distances of the conductive layer 18 is very small compared with the electrical resistance value between the predetermined distances of the canvas 16 and is approximately 0Ω.

  The conductive layer 18 is formed, for example, by blending a predetermined amount of a conductive material with a material containing rubber glue or RFL (resorcin-formaldehyde-latex) composition. The components of the conductive material are composed of silver powder 50 to 70 wt%, graphite powder 2 to 4 wt%, thermoplastic resin 5 to 15 wt%, and isophorone 20 to 40 wt%. The conductive layer 18 is formed by covering the canvas 16 with rubber paste or the like in which a conductive material is mixed before the toothed belt 10 is vulcanized.

  FIG. 2 shows a belt life prediction system according to this embodiment. The life prediction system is provided with driving and driven pulleys 20 and 21. The toothed belt 10 shown in FIG. 1 is hung on the pulleys 20 and 21, and the belt 10 is rotated. The pulleys 20 and 21 have conductive surfaces, and are made of metal, for example.

  In the life prediction system, a resistance measuring device 22, a CPU 23 and a lamp 26 are further provided. The resistance measuring device 22 includes first and second terminals 24 and 25. The terminals 24 and 25 are in contact with the driving and driven pulleys 20 and 21, respectively, so that the resistance measuring device 22 can measure the electric resistance value between the driving and driven pulleys 20 and 21.

  The electrical resistance value measured by the resistance measuring device 22 is sent to the CPU 23. The CPU 23 stores a threshold value in advance, and the CPU 23 emits a lamp 26 and issues a warning when the resistance value exceeds the threshold value.

  The first and second terminals 24 and 25 are formed, for example, in a brush shape, and even if they are in contact with the rotating pulleys 20 and 21, the rotation is not hindered and no abnormal noise is generated. .

  When the toothed belt 10 is not wound around, since the insulation between the pulleys 20 and 21 is performed, the resistance value between them becomes infinite. On the other hand, since the outermost layer of the toothed belt 10 is the conductive layer 18, the electrical resistance value between a part of the outer surface 17 that is a contact surface with the pulleys 20 and 21 and the other part of the outer surface 17 is It is approximately 0Ω. Therefore, when the toothed belt 10 is wound around the pulleys 20 and 21, the pulleys 20 and 21 are electrically connected, and the resistance value between them becomes approximately 0Ω.

  However, when the toothed belt 10 is rotated, the conductive layer 18 is worn. When wear progresses and all of the conductive layers 18 are worn at two or more places in the same width direction of the belt 10, a part of the contact surface with the pulley and the other part of the belt 10 are insulated. Therefore, during the belt rotation, the pulleys 20 and 21 are also temporarily insulated, and the measured electric resistance value rises from about 0Ω to a threshold value (for example, 2 MΩ) or more. When the electrical resistance value rises above the threshold value, the CPU 23 issues a warning from the lamp 26.

  When the belt 10 rotates for a long time and the wear of the conductive layer 18 progresses, the toothed belt 10 causes, for example, tooth chipping or the like, thereby reducing the transmission performance. Therefore, the belt 10 must be replaced after a certain amount of wear has progressed. In other words, in the present embodiment, it is possible to know by a warning that the wear of the belt has progressed to some extent, so that the belt 10 can be properly replaced before the transmission performance of the belt 10 deteriorates.

  As described above, in the present embodiment, by appropriately determining the wear amount of the toothed belt 10, it is possible to grasp the decrease in the transmission performance of the toothed belt 10 and accurately grasp the life of the belt. .

  In the present embodiment, when only a part of the conductive layer 18 is worn, the pulleys 20 and 21 are repeatedly insulated and electrically connected during the rotation of the belt. That is, the electrical resistance measured by the resistance measuring instrument 22 repeats an increase to a threshold value or more and a decrease to a threshold value or less. Therefore, the CPU 23 may issue a warning depending on the time and the number of times that the electrical resistance value per unit time is equal to or greater than the threshold value. As the wear progresses, the time and the number of times that the electric resistance value becomes equal to or greater than the threshold value increase. Therefore, by considering the time and the like, it is possible to more accurately determine the reduction in belt transmission performance.

  In the present embodiment, the conductive layer 18 is covered only on the outer surface of the canvas 16, but may be covered on both the outer surface and the inner surface of the canvas 16. That is, the conductive layer 18 may be provided between the canvas 16 and the belt body 11. In this case, the conductive layer 18 is formed by dipping. That is, the conductive layer 18 is formed by immersing the canvas 16 in an RFL liquid or a rubber paste liquid containing a conductive material before vulcanization molding of the belt.

  In the present embodiment, the terminals 24 and 25 of the resistance value measuring device are in contact with the pulleys 20 and 21, but one terminal is in contact with the pulleys 20 and 21, and the contact surface of the toothed belt 10. You may contact directly. Further, both terminals may be in direct contact with a part of the contact surface of the toothed belt 10 and another part of the contact surface.

  Furthermore, in the present embodiment, the conductive layer 18 is covered over the entire circumference in the longitudinal direction of the belt, but is partially covered if the pulleys 20 and 21 can be temporarily connected during belt rotation. For example, only the half circumference of the belt may be covered. When the conductive layer 18 is covered only half a circle, if the rotation speed of the belt is the same, the electrical resistance value measured by the resistance measuring device 22 repeats the above and below the threshold value at regular intervals. Therefore, the CPU 23 may issue a warning when an abnormality occurs in this cycle.

  Next, a second embodiment of the present invention will be described. The second embodiment is different from the first embodiment only in the components of the conductive material. That is, the components of the conductive material of the second embodiment are composed of graphite powder 10 to 30 wt%, carbon black 5 to 20 wt%, thermoplastic resin 20 to 40 wt%, and isophorone 20 to 40 wt%. In the conductive material of the second embodiment, graphite is used instead of silver. Therefore, the conductivity of the conductive layer of the second embodiment is lower than the conductivity of the conductive layer of the first embodiment, and the battery resistance value for a predetermined distance of the conductive layer 18 is, for example, about 300 kΩ.

  Thereby, in 2nd Embodiment, although the electrical conductivity of a conductive layer becomes low compared with 1st Embodiment, the power transmission belt which concerns on this invention can be manufactured with a cheaper material.

  Next, a third embodiment of the present invention will be described. In the third embodiment, the difference from the first embodiment is only the component of the conductive material. That is, in the third embodiment, the conductive material is a mixture of the conductive material of the first embodiment and the conductive material of the second embodiment in a ratio of 1: 1. The conductivity of the conductive layer in the third embodiment is lower than the conductivity of the conductive layer in the first embodiment, but is higher than the conductivity of the conductive layer in the second embodiment. The battery resistance value for a predetermined distance is, for example, approximately 100 kΩ.

  As described above, in the third embodiment, a conductive layer having high conductivity can be manufactured using an inexpensive material.

The sectional view of the power transmission belt in the embodiment of the present invention is shown. 1 shows a schematic diagram of a belt life prediction system in an embodiment of the present invention. FIG.

Explanation of symbols

10 Toothed belt 11 Belt body 16 Canvas (inner layer)
18 Conductive layer 22 Resistance meter

Claims (6)

A transmission having a contact surface with the pulley, which is formed by covering the first and second pulleys having conductivity and being rotated and coated with a conductive layer having a higher conductivity than the inner layer on the outer side of the inner layer. Belt,
Measuring means for measuring the electrical resistance between the first and second pulleys;
Determination means for determining a decrease in transmission performance of the transmission belt with respect to a pulley due to an increase in the electrical resistance due to wear of the contact surface;
The conductive layer of the transmission belt is formed so as to be partially coated on the inner layer in the longitudinal direction of the belt so that the first and second pulleys can be temporarily connected during belt rotation .
The belt life prediction system characterized in that the determination means determines a decrease in transmission performance of the transmission belt with respect to a pulley based on an abnormality in an increase / decrease cycle of the electrical resistance .   The belt life prediction system according to claim 1, wherein the transmission belt has a belt main body, and the inner layer is a canvas covering one surface of the belt main body.   The belt life prediction system according to claim 1, wherein the inner layer is an insulator.   The belt life detection system according to claim 1, wherein the conductive layer is formed of a material including at least one of a rubber paste and an RFL composition and a conductive material. The belt life detection system according to claim 4 , wherein the conductive material contains at least one of silver and graphite. In a belt life prediction method for determining a reduction in the transmission performance of a transmission belt due to wear and wear on a contact surface with the first and second pulleys having electrical conductivity,
The contact surface is formed by covering the outer side of the inner layer with a conductive layer having higher conductivity than the inner layer,
The electrical resistance between the first and second pulleys is measured, and the increase in the electrical resistance determines the reduction in transmission performance of the transmission belt with respect to the pulleys,
Conductive layer of the transmission belt, to allow conduction between temporarily the first and second pulleys in the belt rotation, which is formed covering the part on the inner layer in the belt longitudinal direction, the electric resistance based rise of and down cycle abnormalities, belt life prediction method characterized that you determine the degradation of the transmission performance for the pulley of the transmission belt.

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