JP2008304204A - Toothed belt deterioration evaluation device, and method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To evaluate accurately a deterioration degree, even if a toothed belt used for a belt transmission device has large load fluctuations. <P>SOLUTION: The toothed belt 13 is laid between a driving pulley 11 and a driven pulley 12. Each slit-shaped notch is provided on both sides of a tooth for measurement which is one tooth of the driving pulley 11, and each strain gauge is stuck on both side faces of the tooth for measurement. A signal from each strain gauge is transmitted to a control device 14 via a shaft. A tooth load applied to the tooth for measurement is calculated by the control device 14. The degree of deterioration of the toothed belt 13 is evaluated from the calculated tooth load. When it is determined in evaluation that the belt reaches a replacement time, a warning is issued from a warning device 15. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an apparatus and method for evaluating the degree of deterioration of a toothed belt or predicting its life, and more particularly to evaluating the degree of deterioration of a timing belt used in an automobile engine or predicting its life. The present invention relates to an apparatus and a method thereof.

  As a method for predicting the life of a timing belt used in an automobile engine, for example, a method of predicting the life based on visual inspection of the belt or belt elongation is known. However, the visual inspection requires experience and the timing belt is attached to the inside of the engine, so that it is not suitable for the visual inspection. In addition, since the life of the belt is affected by poor meshing due to the contraction of the belt, the life of the belt cannot be accurately predicted based on the extension of the belt.

For such a problem, a method for detecting the effective tension of the belt and predicting the service life based on the effective tension of the belt has been proposed as a system for determining the replacement timing of the toothed transmission belt provided in general industrial machines and the like. (Patent Document 1).
JP 2005-344807 A

  However, since the effective tension is the total of the tooth loads of the belt, even if the tooth load applied to one tooth is increased due to poor meshing due to the elongation or wear of the belt, they are offset in the effective tension. The effect hardly appears. Therefore, when the life of the toothed belt is predicted from the effective tension, the increase in local tension due to the belt performance deterioration is overlooked, and it is difficult to accurately evaluate the degree of deterioration of the belt or predict the life. In particular, in application to an automobile engine, since the load fluctuation is large, there is a possibility that the load applied to one tooth of the belt is increased. In such a case, the evaluation based on the effective tension is not sufficient.

  An object of the present invention is to accurately evaluate the degree of deterioration of a toothed belt, and in particular, to accurately evaluate the degree of deterioration of a toothed belt used in a belt transmission device having a large load fluctuation.

  A toothed belt deterioration evaluation apparatus of the present invention is an apparatus for evaluating the degree of deterioration of a toothed belt in a belt transmission system using a toothed belt, and includes a tooth load measuring means for measuring a tooth load, a tooth And an evaluation means for evaluating the degree of deterioration of the toothed belt based on the load.

  The evaluation means preferably performs the evaluation based on the maximum tooth load of the measured tooth load, and further the evaluation means performs the evaluation based on the peak value of the maximum tooth load along the rotational speed of the belt transmission system. Is preferred.

  The tooth load measuring means is provided, for example, on the teeth of the driving pulley of the belt transmission system. Moreover, it is preferable that a toothed belt deterioration evaluation apparatus is provided with the output means which outputs the result of evaluation. The evaluation is, for example, an evaluation relating to the belt replacement timing or the belt life.

  The toothed belt deterioration evaluation method of the present invention is a method for evaluating the degree of deterioration of a toothed belt in a belt transmission system using a toothed belt, based on a step of measuring a tooth load and the tooth load. And a step of evaluating the degree of deterioration of the toothed belt.

  As described above, according to the present invention, the degree of deterioration of the toothed belt can be accurately evaluated, and the degree of deterioration can be accurately determined even for a toothed belt used in a belt transmission device having a large load fluctuation. Can be evaluated.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing the overall configuration of a belt life prediction apparatus according to an embodiment to which the present invention is applied. The belt life prediction device is used in a belt transmission system using a toothed belt such as a belt transmission system of a vehicle engine using a timing belt or a power transmission system of a general industrial machine.

  The belt life prediction apparatus 10 is applied to a belt transmission system including a driving pulley 11, a driven pulley 12, and a toothed belt 13 wound around these. For example, in the case of a vehicle engine, the driving pulley 11 is a crankshaft pulley, and the driven pulley 12 is a camshaft pulley, for example. The belt transmission system may include a plurality of driven pulleys. In the case of a vehicle engine, an auxiliary pulley such as an oil pump or a water pump is usually provided, and a tensioner is provided on the belt rear side. The pulley is engaged.

  The driving pulley 11 is provided with a sensor for measuring a tooth load applied to the pulley teeth, and a signal from the sensor is sent to the control device 14 via the rotating shaft of the driving machine provided with the driving pulley 11. The control device 14 calculates the tooth load, and based on this, the degree of deterioration or the life of the belt is evaluated. In this embodiment, for example, when the tooth load exceeds a predetermined value set in advance, for example, the warning device 15 issues a warning notifying that the belt replacement time has come. Examples of the warning device include lighting of a lamp, display of characters on a display, a device that emits a warning sound, and the like. Further, for example, the life expectancy of the belt may be estimated from the tooth load based on data obtained experimentally in advance, and a display corresponding to the life expectancy (travel distance and time until replacement) may be performed.

  FIG. 2 shows a front view of the driving pulley 11 of the present embodiment, and FIG. 3 shows a rear view. As shown in FIGS. 2 and 3, the driving pulley 11 is a toothed pulley having, for example, 22 teeth, and includes 21 normal teeth 16 and one tooth 17 (shaded portion) for tooth load measurement. Is provided. While the 21 teeth 16 are integrally formed on the outer peripheral surface of the driving pulley 11, the teeth 17 for measuring the tooth load are slit-like on both sides in order to measure the load applied to the teeth. Incisions are provided. That is, the teeth 17 are cantilevered by extending radially outward from a predetermined position closer to the center rather than from the outer peripheral surface of the driving pulley 11.

  FIG. 4 shows a partially enlarged view around the tooth 17 for tooth load measurement. As shown in FIG. 4, strain gauges 18 </ b> A and 18 </ b> B, for example, are attached to both side surfaces 17 </ b> A and 17 </ b> B on the proximal end side of the teeth 17 as sensors for measuring tooth loads. That is, in the present embodiment, the tooth load applied to the belt teeth is estimated by measuring the distortion of the teeth 17 of the driving pulley. In the present embodiment, the resultant force of the tooth surface load and the tip surface frictional force is measured, but it may be configured to measure only the tooth surface load.

  Signals from the strain gauges 18A and 18B are guided to a shaft shaft (not shown) to which the driving pulley 11 is attached via a signal line, and output to a fixed part such as an engine block via brush contact, for example. To the control device 14. In the control device 14, the tooth load of the tooth 17 is calculated based on the change in the signals from the strain gauges 18 </ b> A and 18 </ b> B, and a warning is issued in the warning device 15 when the calculated tooth load is equal to or greater than a predetermined value.

  Next, with reference to FIG. 5 to FIG. 10, the principle of the evaluation method of the degree of deterioration of the belt in the present embodiment will be described.

  FIGS. 5 and 6 are graphs showing the relationship between the rotational speed of the belt transmission system and the maximum tooth load measured at each rotational speed. Data are shown for a belt that is worn and cracked in the tooth rubber. 5 and 6 show the maximum tooth loads Ln + and Lu + in the belt running direction (+ side) for the new belt and the market running belt, and the maximum tooth load Ln− in the opposite direction (− side) of the belt running direction. Lu- is shown.

  FIG. 5 exemplifies a case where the difference in maximum tooth load between the new belt and the market running belt is remarkable on the + side, and the peak value Pn + of each graph of the + side maximum tooth load Ln +, Lu +, Pu + is 20% higher for market running belts. On the other hand, FIG. 6 exemplifies a case where the difference in maximum tooth load between the new belt and the market running belt is significant on the − side, and the peak values of the −side maximum tooth loads Ln− and Lu− are shown in the graph. Pn- and Pu- are 50% higher on the market running belt.

  FIG. 7 is an example of a graph showing the load sharing in each tooth of the driving pulley when the peak values Pn + and Pu + of FIG. 5 are measured. The horizontal axis corresponds to the tooth numbers (Nos. 1 to 22) sequentially assigned to the respective teeth, and the graph shows the tooth load applied to each tooth when the driving pulley is in a predetermined phase.

  In FIG. 7, the tooth load Ldu + shared by each tooth of the market running belt is, for example, tooth No. The peak value Pu + is taken at 2, which corresponds to the tooth load at the time of biting. As shown in the figure, in the market running belt, the tooth No. The tooth load shared by the two teeth is significantly larger than the tooth load shared by the other teeth. This is due to an increase in tooth load at the time of meshing due to a meshing abnormality caused by belt elongation and wear caused over time. On the other hand, with the tooth load Ldn + shared by each tooth of the new belt, the tooth No. In FIG. 4, the peak value Pn + is taken, but there is no significant difference in the tooth load sharing among the teeth around which the belt is wound.

  Next, FIG. 8 shows the effective tension values of the new belt and the market running belt when the load sharing of the driving pulley is shown in FIG. As shown in FIG. 7, the peak values Pn + and Pu + of the maximum tooth load on the + side are greatly different between the new belt and the market running belt, but the effective tension at that time is different as shown in FIG. The difference is slight.

  FIG. 9 is an example of a graph showing the load sharing in each tooth of the driving pulley when the peak values Pn− and Pu− of FIG. 6 are measured. In FIG. 9, the tooth load Ldu− shared by each tooth of the market running belt is, for example, tooth No. At 6, the peak value Pu- is taken, which corresponds to the tooth load at the time of chewing. As shown in the figure, in the market running belt, the tooth No. The tooth load shared by 6 teeth is significantly larger than the tooth load shared by other teeth. Similar to the peak value Pu +, this is due to an increase in the negative side tooth load at the time of biting due to an abnormal meshing due to the elongation and wear of the belt caused by running. On the other hand, with the tooth load Ldn− of the new belt, the tooth No. Although the peak value Pn− is taken at 6, there is no significant difference in the tooth load sharing among the teeth around which the belt is wound as in the + side.

  FIG. 10 shows the effective tension values of the new belt and the market running belt when the load sharing of the driving pulley is shown in FIG. As in the case of the maximum tooth load on the + side, in FIG. 10, the difference in effective tension on the − side between the new belt and the market running belt is slight.

  As described above, even for belts that have been run on the market, the root canvas is worn, and the tooth rubber has cracks, the effective tension is not significantly different from that of a new belt. It is not always effective to use the value of effective tension for life prediction. On the other hand, as shown in FIGS. 5 and 6, the maximum tooth load is large on the + side or − side between the new and marketed belts, and the difference in the peak value of the maximum tooth load is particularly significant. It is.

  Therefore, as in this embodiment, in the belt transmission system, the tooth load during travel is measured, and the degree of belt deterioration is evaluated based on the measured tooth load, or the life is predicted, thereby accurately evaluating the degree of deterioration. It is possible to predict the life and discriminate the belt replacement time. Thereby, the reliability of the belt transmission system can be improved.

  In the present embodiment, the mechanism for measuring the tooth load is provided on the driving pulley, but it is also possible to provide such a mechanism on another pulley or a plurality of pulleys. Further, a plurality of teeth of one pulley can be used for tooth load measurement.

It is a schematic diagram which shows the structure of the whole belt lifetime prediction apparatus to which this invention is applied. It is a front view of the driving pulley of this embodiment. It is a rear view of the driving pulley of this embodiment. It is the elements on larger scale around the tooth for tooth load measurement. It is a graph which shows an example of the maximum tooth load measured in each rotational speed. It is a graph which shows another example of the maximum tooth load measured in each rotation speed. FIG. 6 is a graph showing the tooth load sharing applied to each tooth of the driving pulley when the peak values Pn + and Pu + of FIG. 5 are measured. The value of the effective tension of the new belt and the market running belt when the load sharing of the driving pulley is shown in FIG. 7 is shown. FIG. 7 is a graph showing a tooth load sharing applied to each tooth of the driving pulley when the peak values Pn− and Pu− of FIG. 6 are measured. The value of the effective tension of the new belt and the market running belt when the load sharing of the driving pulley is shown in FIG.

Explanation of symbols

10 Belt Life Prediction Device 11 Driving Pulley 12 Driven Pulley 13 Toothed Belt 14 Control Device 15 Warning Device 17 Teeth for Measuring Tooth Load 18A, 18B Strain Gauge

Claims (7)

  A device for evaluating the degree of deterioration of the toothed belt in a belt transmission system using a toothed belt, comprising: tooth load measuring means for measuring tooth load; and deterioration of the toothed belt based on the tooth load. And a toothed belt deterioration evaluation device, comprising: an evaluation means for evaluating the degree of the belt.   The toothed belt deterioration evaluation device according to claim 1, wherein the evaluation unit performs the evaluation based on a maximum tooth load of the measured tooth load.   3. The toothed belt deterioration evaluation device according to claim 2, wherein the evaluation unit performs the evaluation based on a peak value of the maximum tooth load along a rotation speed of the belt transmission system.   2. The toothed belt deterioration evaluation device according to claim 1, wherein the tooth load measuring means is provided on a tooth of a driving pulley of the belt transmission system.   The toothed belt deterioration evaluation apparatus according to claim 1, wherein the toothed belt deterioration evaluation apparatus includes an output unit that outputs the result of the evaluation.   The toothed belt deterioration evaluation apparatus according to claim 1, wherein the evaluation is an evaluation related to a belt replacement time or a belt life.   A method for evaluating the degree of deterioration of the toothed belt in a belt transmission system using a toothed belt, the step of measuring a tooth load, and evaluating the degree of deterioration of the toothed belt based on the tooth load. And a toothed belt deterioration evaluation method.

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