JP4478508B2 - Belt replacement time determination system - Google Patents

Description

  The present invention relates to a system for determining the replacement timing of a transmission belt provided in a general industrial machine or the like.

  When the transmission belt is run for a certain period of time, the meshing portion with the pulley is worn and the remaining strength of the core wire is lowered, and eventually damage such as breakage and chipping occurs. When the belt is broken or the like, the transmission action between the transmission belt and the pulley is lowered. Therefore, the transmission belt needs to be replaced before breaking or damage to the teeth.

  Therefore, as described in Patent Document 1, for example, a method of estimating the belt life by observing the surface of the power belt with the naked eye and capturing changes in appearance is known. However, if the belt life is determined by visual observation, it is impossible to determine a decrease in the strength of the core wire embedded in the belt, and the determination depends on the experience of the measurer, so the belt life is accurately determined. It is difficult to do. Furthermore, when the transmission belt is provided inside the engine, for example, it is impossible to sequentially confirm the occurrence of wear and cracks by visual inspection.

Conventionally, as described in Patent Document 2, for example, a method for predicting the life by the elongation of the belt is known. However, since the belt life depends not only on the belt elongation but also on the belt meshing abnormality due to the effect of the belt shrinkage, it cannot always be judged only by the belt elongation.
JP-A-9-329595 JP-A-9-79329

  The present invention has been made in view of the above problems, and provides a belt replacement timing determination system capable of determining the replacement timing of a toothed belt in consideration of not only belt elongation but also other effects. The purpose is to do.

  A first belt replacement time determination system according to the present invention is a belt replacement time determination system for determining the replacement time of a transmission belt wound around a pulley, and the pulley is rotated over the entire rotation speed range. Measuring means for measuring a measurement value that changes in conjunction with the load torque acting on the pulley, and determining whether or not the measurement value falls within a preset allowable range within the rotational speed range. And determining means for determining that it is time to replace the transmission belt when it is determined that it is not within.

  When the measurement means measures the measurement values for a plurality of rotation speeds and calculates the measurement values at the respective rotation speeds that are not measured from the respective measurement values, the determination means calculates the approximation. It is preferable to determine whether or not the measured value falls within an allowable range. The measured value is preferably an effective tension.

  When the transmission belt is wound around the driven and driven pulleys, the measured value may be the rotational phase difference of the driven pulley relative to the driven pulley. More preferably, the rotational phase difference is a difference in rotational speed between the driving pulley and the driven pulley.

  While the transmission belt is attached to the pulley with standard attachment tension and the pulley is rotated over the entire rotation speed range, the measured value measured at each rotation speed is taken as the reference value, and the allowable range is the reference value. It is preferable to set based on this. The allowable range is preferably set around the reference value. The allowable range is preferably determined according to the number of rotations when the measured value is measured.

  A second belt replacement time determination system according to the present invention is a belt replacement time determination system for determining the replacement time of a transmission belt wound around a pulley, and the pulley is rotated over the entire rotation speed range. In addition, the relationship between the measurement means for measuring the measurement value that changes in conjunction with the load torque acting on the pulley at a plurality of rotation speeds, the measured plurality of measurement values, and the rotation speed at which each measurement value is measured. The calculation means for obtaining the function shown, and whether the function falls within the allowable range of the measurement value determined according to the rotational speed, and when it is determined that it is not within the allowable range, Discriminating means for discriminating that it is present.

  A belt replacement time determination method according to the present invention is a belt replacement time determination method for determining a replacement time of a transmission belt wound around a pulley, wherein the pulley rotates while the pulley rotates over a predetermined rotation speed range. A measurement step for measuring a measurement value that changes in conjunction with a load torque acting on the motor, and whether the measurement value falls within a preset allowable range within the rotational speed range, and is not within the allowable range A determination step of determining that it is time to replace the transmission belt.

  A second belt replacement time determination method according to the present invention is a belt replacement time determination method for determining a replacement time of a transmission belt wound around a pulley, and the pulley is rotated over a predetermined rotation speed range. In addition, the relationship between the measurement step for measuring the measurement value that changes in conjunction with the load torque acting on the pulley at a plurality of rotation speeds, the measured plurality of measurement values, and the rotation speed at which each measurement value is measured is shown. A calculation step for obtaining a function to be shown, and whether or not the function falls within the allowable range of the measurement value determined according to the rotational speed. And a determination step of determining that there is.

  According to the present invention, it is possible to determine the belt replacement time by measuring the measured value that fluctuates in accordance with the torque fluctuation over the entire predetermined number of rotations. Therefore, it is possible to easily determine the belt replacement time. Can do.

Embodiments of the present invention will be described below with reference to the drawings.
With reference to FIGS. 1-4, the belt replacement time discrimination | determination system which concerns on embodiment of this invention is demonstrated. In the present embodiment, a case where a variable load occurs, such as cam driving, will be described. As shown in FIG. 1, in this system, driving and driven pulleys 10 and 11 are provided, and a toothed belt 12 is wound around the driving and driven pulleys 10 and 11. A shaft 13 is integrally connected to the center of the driving pulley 10. The rotation of the shaft 13 is transmitted to the driven pulley 11 via the driving pulley 10 and the toothed belt 12.

  A known strain gauge 14 is attached to the shaft 13, and a known rotational speed detector 24 is further provided. The strain gauge 14 detects a strain generated in the shaft 13, and a torque Tr acting on the driving pulley 10 is obtained in the CPU 15 based on the strain. The rotation speed detector 24 detects the rotation speed n of the shaft 13, that is, the driving pulley 10, and the detected rotation speed n is sent to the CPU 15. A memory 17, a ROM 18, and an alarm device 16 are connected to the CPU 15.

In FIG. 2, an example of the graph of the measurement result of torque Tr by the strain gauge 14 is shown. As shown in FIG. 2, the torque Tr periodically changes between the positive (+) direction and the reverse (−) direction, and changes one cycle every time the driving pulley 10 makes one rotation. Here, the CPU 15 selects only the maximum value Tr _max (value of the inflection point) when the torque is applied in the positive direction, and the selected torque maximum value Tr _max is calculated from the effective tension Te according to the equation (1). Is done.

Te = Tr _max / r (1)
(Where r is the pitch circle radius of the driving pulley 10)

  The method for discriminating the exchange time of this belt exchange time discriminating system will be described in detail with reference to FIG. In the belt replacement time determination system, when the rotation of the driving pulley 10 starts, the rotation speed of the toothed belt 12 increases to a measurement rotation speed range X (for example, 1500 to 2500 rpm). Here, the toothed belt 12 is used constantly, that is, with a high frequency of use, while the rotational speed varies throughout the rotational speed range X, that is, between the rotational speed ranges X.

While the driving pulley 10 rotates over the entire measurement rotational speed range X, the CPU 15 measures the effective tension Te, for example, every 1/60 seconds, and stores the effective tension Te and the rotational speed n at that Te in the memory 17. Is done. On the other hand, tolerance Te _r of the effective tension in the measured speed range X is stored in advance in the ROM 18. Tolerance Te _r is set for each rotation speed n, constituting the allowable region α as shown in FIG. That is, the allowable area α changes according to the rotation speed n.

The effective tension Te and the rotation speed n stored in the memory 17 are sequentially read out. Each effective tension Te is the rotational speed n of the effective tension Te is measured, it is within the allowable range Te _r is determined. Here, the effective tension Te is determined not to be within Te _r, lamp alarm 16 is caused to emit light, a warning is issued. With this warning, the user determines that the toothed belt 12 must be replaced. That is, in the present embodiment, it is determined whether or not the measured effective tension Te is within the allowable range α in the rotation speed when the effective tension Te is measured in the measurement rotation speed range X that is frequently used. The belt replacement time is determined.

Next will be described in detail with reference to FIG. 4 a method of setting the stored Te _r in ROM 18. Graphs (1), (2), and (3) in FIG. 4 show the relationship between the mounting tension and the effective tension when the belt mounting tension is forcibly set to T ₀ , 2T ₀ , and 1/4 T ₀ , respectively. The relationship between the number of rotations and the effective tension is shown.

Generally, the belt is attached with a standard attachment tension T ₀ immediately after attachment. With the standard mounting tension T ₀ , the belt can efficiently transmit power and can have high durability.

However, the mounting tension varies with the use of the belt. For example, when the belt hardens and shrinks due to the influence of adhesion of water, oil, etc., the mounting tension increases. If the mounting tension increases, for example, if the mounting tension exceeds twice the standard mounting tension T ₀ , the toothed belt 12 is over tensioned and has deteriorated, so it may be prematurely broken. . Therefore, it is desirable to replace the toothed belt 12 when the mounting tension becomes 2T ₀ by use.

Further, for example, when the belt is stretched due to bending fatigue of the core wire or wear of the tooth surface portion, the mounting tension decreases. When the mounting tension decreases, for example, when the mounting tension becomes about 1/4 times the standard mounting tension T ₀ , the toothed belt 12 may cause tooth skipping due to increased span vibration or abnormal meshing with the pulley. , Causing tooth chipping or cutting early. Therefore, it is desirable to replace the toothed belt 12 when the mounting tension becomes about 1/4 T ₀ by use.

That is, the belt is desirably installation tension rotates at about 1 / 4T ₀ ~2T _0, the mounting tension aging exceeds this range, it is desirable to replace.

However, it is difficult to measure the mounting tension after the belt is incorporated into the device. Also, the mounting tension cannot be measured while the belt is rotating. On the other hand, the effective tension of the belt is easy to measure as described above, and can be measured during rotation. Further, the effective tension changes with the number of rotations as shown in FIG. 4, but if the mounting tension is constant, the changing tendency is the same. Therefore, if the mounting tension remains the standard mounting tension T ₀ , the change tendency of the effective tension is the same.

On the other hand, for example, when the mounting tension changes from the standard mounting tension T ₀ , the change tendency of the effective tension with respect to the rotational speed also changes. The change trend of the effective tension as installation tension is if deviation from a standard installation tension T _0, the change trend is different.

That is, when the mounting tension is 2T ₀ , the change tendency is greatly different from the graph (1) as shown in the graph (2) in FIG. Further, when the mounting tension is 1 / 4T ₀ , the change tendency is also greatly different from that of the graph (1) as shown in the graph (3). As described above, when the belt mounting tension changes to 2T ₀ or 1 / 4T ₀ , it is desirable to replace the belt. That is, the toothed belt 12 may be replaced when the change tendency of the effective tension greatly deviates from the graph (1) and approaches the change tendency of the graph (2) or the graph (3). desirable.

Therefore, in the present embodiment, when the allowable region α is attached at the attachment tension T ₀ , the rotational speed is varied in the measurement rotational speed range X, and the standard effective tension for each rotational speed is measured within the rotational speed range. However, it is determined based on these measured standard effective tensions. Specifically, around the standard effective tension in each of the rotational speed for each, set the ± 10% range of the standard effective tension as tolerance Te _r. In this embodiment, for example, the standard effective tension is measured every 50 rpm, and the standard effective tension at other rotational speeds is proportional to the rotational speed based on the standard effective tensions measured before and after the rotational speed. When it increases or decreases, it is calculated by approximation.

For example, when the belt is attached with a standard attachment tension T ₀ and the attachment tension increases to 2 T ₀ by use, as shown in FIG. 4, the measured value of the effective tension for each revolution number is 1500 rpm to 1900 rpm. some time, but its effective tension is within an allowable range Te _r, when the rotational speed exceeds 1900 rpm, the effective tension becomes the allowable range Te _r out. Therefore, when the mounting tension reaches 2T ₀ due to use, when the driving pulley is rotated over the entire rotation speed range X, the CPU 15 issues a warning, which allows the user to properly determine the replacement time. it can.

On the other hand, if the installation tension is reduced to 1 / 4T _0, as shown in FIG. 4, the measured value of the effective tension of each rotation speed, when the rotation speed is 1500rpm~1800rpm, the effective tension tolerance Te _r Is within. However, when the rotational speed exceeds 1800 rpm, so that the effective tension becomes the allowable range Te _r out, CPU 15 issues a warning. Therefore, when the mounting tension is reduced to 1/4 T ₀ due to use, when the driving pulley is rotated over the entire rotation speed range X, the CPU 15 issues a warning, whereby the user properly determines the replacement time. can do.

As described above, in the present embodiment, determines the measurement speed region in X, the effective tension Te at a certain speed, whether the advance within that have been set tolerance Te _r for each rotational speed Thus, the replacement time can be determined.

Further, if the effective tension Te is measured only when the rotational speed is one condition (for example, 1500 rpm), for example, the mounting tension is increased and the replacement time has been reached (for example, the mounting tension is 2T ₀ ). However, since the effective tension Te at 1500 rpm is substantially equal to that at the mounting tension T ₀ , the replacement time cannot be accurately determined. On the other hand, in the present embodiment, since the effective tension is measured over the entire measurement rotational speed range X, the change tendency of the effective tension can be detected properly, and the belt replacement time can be accurately determined.

  A second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the effective tension function Te = f (n) is calculated from the effective tension and the rotational speed stored in the memory, and it is determined whether the function f (n) is within the allowable range α. As a result, the replacement time is determined. In the following, only the differences from the first embodiment will be described for the second embodiment.

In the second embodiment, while the driving pulley 10 is rotated in the measurement speed region X, the CPU 15, for example, the effective tension Te _n every 1/60 second is measured, the effective tension (Te _1, Te ₂ , Te ₃ ,..., Te _n ) and the number of rotations (n ₁ , n ₂ , n ₃ ,..., N _n ) at the effective tension are stored in the memory 17. Each effective tension stored in the memory 17 and each rotation speed at the effective tension are read every predetermined time (for example, 10 seconds), and the relationship between the effective tension Te measured in the 10 seconds and the rotation speed n. As shown in FIG. 5, Te is calculated as Te = f (n) within a predetermined rotational speed range, and it is determined whether or not the function f (n) falls within the allowable range α. Incidentally, the rotational speed is measured within a predetermined time, n ₁ in forward rotation speed is small, n _2, n _3, ..., a n _n, the effective tension _{Te 1, Te 2, Te 3} , ..., Te n is each of the rotational speed _{n 1, n 2, n 3} , ..., it is effective tension measured at n _n.

Here, the function f (n) is a set of a plurality of linear functions. Each linear function is calculated between two adjacent rotation speeds, that is, between n ₁ -n ₂ , n ₂ -n ₃ ,..., N _n-1 -n _n . Each linear function, the two rotational speed (for example n _n-1, n _n), the effective tension (e.g. Te _n-1, Te _n) at that time, the effective tension Te is, the rotational speed n Calculated as a proportional function. That is, when the function f (n) is graphed, as shown in FIG. 5, the effective tensions measured at adjacent rotational speeds are connected by straight lines. It is to be noted that the same rotational speed n _n effective tension Te _n measured in the case there are a plurality, are used to their average value draws a trendline as effective tension Te _n.

  As described above, in the present embodiment, the relationship between the effective tension and the rotational speed is calculated as the function f (n), so that the replacement time can be determined more accurately. Note that the function f (n) may be calculated as an approximate function. In this case, the function f (n) may be obtained from the measured effective tension Te and the rotation speed n at that time by, for example, the least square method. The approximate function may be calculated by, for example, linear approximation, logarithmic approximation, polynomial approximation, power approximation, exponential approximation, or the like.

In the second embodiment, the function f (n) is obtained from the effective tension Te and each rotation speed n, but from the effective tension Te at each rotation speed measured within a predetermined time, a predetermined time is obtained. The effective tension Te at each rotational speed that is not measured in the above may be approximated. In this case, both the measured value and the approximate value obtained, similarly to the first embodiment, in each rotation speed n, it is determined whether to be within the allowable range Te _r, replacement time may be determined. Note that the effective tension Te (approximate value) that is not measured is approximated and calculated by increasing or decreasing in proportion to the rotational speed based on the effective tension Te measured before and after the rotational speed.

  A third embodiment will be described. In the first embodiment, the effective tension Te is measured, and the replacement time is determined based on the effective tension Te. In this embodiment, instead of the effective tension Te, the effective rotational phase difference de is measured. The replacement time is determined based on the effective rotational phase difference de. FIG. 6 shows a belt replacement time determination system in the third embodiment. In addition, the same code | symbol is attached | subjected to the same member as 1st Embodiment. Only differences from the first embodiment will be described below.

  As shown in FIG. 6, the first shaft 33 and the second shaft 34 rotate together with the driving pulley 10 and the driven pulley 11, respectively. The driving force of the first shaft 33 is the driving pulley 10 and the toothed belt 12. And the second pulley 34 via the driven pulley 11. The first shaft 33 and the second shaft 34 are provided with rotational speed detectors 24 and 25, and the rotational speed detectors 24 and 25 detect the rotational speeds of the driving pulley 10 and the driven pulley 11, respectively.

  The rotational speeds detected by the respective rotational speed detectors 24 and 25 are sent to the CPU 15. In the CPU 15, the rotational phase difference d of the driven pulley 11 with respect to the driving pulley 10 is obtained based on the detected rotational speed difference and the diameter of the pitch circle of the pulleys 10 and 11. Here, the rotational phase difference d is obtained as a length on the pitch line of the driven pulley 11 with respect to the driving pulley 10, and is a deviation amount of the driven pulley 11 with respect to the rotating driving pulley 10 when the stop time is zero. .

FIG. 7 shows the relationship between the rotational phase difference d and the torque Tr acting on the driving pulley 10. As the torque Tr increases, the power transmitted from the driving pulley 10 to the driven pulley 11 also increases. The greater the power transmitted, the greater the rotational phase difference. Accordingly, as shown in FIG. 7, the rotational phase difference d is periodically changed between the positive (+) direction and the reverse (−) direction in the same cycle in conjunction with the torque Tr, and the driving pulley 10 makes one rotation. Each cycle changes by one cycle. In the CPU 15, only the maximum value d _max (value of the inflection point) when the torque is applied in the positive direction is selected, and the maximum value d _{max of} the selected rotation phase difference d is set as the effective rotation phase difference de. .

As in the first embodiment, it is determined whether or not the measured effective rotational phase difference de is within the allowable region β shown in FIG. 8 at the measured rotational speed n. As in the first embodiment, the permissible area β is configured by a permissible range de _r that is different for each rotation speed, and each de _r is stored in the ROM 18. Therefore, the CPU 15 determines whether each measured effective rotational phase difference de is within an allowable range de _r corresponding to the measured rotational speed n, thereby determining the first implementation. As with the configuration, the replacement time is determined.

Next will be described in detail with reference to FIG. 9 tolerance de _r setting method stored in ROM 18. The graph of FIG. 9 (1) (2) (3), before each belt use, forcedly T ₀ the installation tension, 2T _0, 1 / 4T ₀ and rotating speed and the effective rotational phase difference when the Show the relationship.

As described above, the belt is desirably installation tension rotates at about 1 / 4T ₀ ~2T _0, the mounting tension aging exceeds this range, it is desirable to replace. On the other hand, the effective rotational phase difference de changes with the rotational speed as shown in FIG. 9, but if the mounting tension is constant, the changing tendency is the same. Therefore, if the mounting tension remains the standard mounting tension T ₀ , the change tendency of the effective rotational phase difference is the same.

On the other hand, for example, when the mounting tension changes from the standard mounting tension T ₀ , the changing tendency of the effective rotational phase difference de with respect to the rotational speed also changes. Further, as shown in the graphs (2) and (3), the change tendency of the effective rotation phase difference de is different as the attachment tension deviates from the standard attachment tension T ₀ .

That is, as shown in the graph (2) of FIG. 9, when the mounting tension is 2T ₀ , the change tendency is greatly different from that of the graph (1). Further, when the mounting tension becomes 1 / 4T ₀ as shown in the graph (3), the change tendency thereof is also greatly different from the graph (1). As described above, when the belt mounting tension changes to 2T ₀ or 1 / 4T ₀ , it is desirable to replace the belt. That is, the toothed belt 12 is replaced when the change tendency of the effective rotational phase difference de greatly deviates from the graph (1) and approaches the change tendency of the graph (2) or the graph (3). It is desirable.

Therefore, in the present embodiment, the permissible region β is the standard effective rotational phase difference for each rotational speed within the rotational speed range when the rotational speed is varied in the measured rotational speed range X when mounted at the mounting tension T _0. Is determined based on these measured standard effective rotational phase differences. Specifically, a range of ± 10% of the standard effective rotational phase difference is set as the allowable range de _r around the standard effective rotational phase difference for each rotational speed. In this embodiment, for example, the standard effective rotational phase difference is measured every 250 rpm, and the standard effective rotational phase difference at other rotational speeds is based on the standard effective rotational phase difference measured before and after the rotational speed. Approximately calculated by increasing or decreasing in proportion to the rotation speed.

Here, for example, when the mounting tension increases to 2T ₀ , as shown in FIG. 9, the measured value of the effective rotational phase difference for each rotational speed is, when the rotational speed is 1500 rpm to 1900 rpm, the effective rotational phase difference is Within the predetermined range, when the rotational speed exceeds 1900 rpm, the effective rotational phase difference is outside the predetermined range. Therefore, when the mounting tension reaches 2T ₀ due to use, when the driving pulley is rotated over the entire rotation speed range X, the CPU 15 issues a warning, which allows the user to properly determine the replacement time. it can.

On the other hand, similarly, when the mounting tension is reduced to 1/4 T ₀ , as shown in FIG. 9, the measured value of the effective rotation phase difference for each rotation speed is the effective rotation when the rotation speed is 1500 rpm to 1750 rpm. The phase difference is within a predetermined range. However, if the rotational speed exceeds 1750 rpm, the effective rotational phase difference is outside the predetermined range, so the CPU 15 issues a warning. Therefore, when the mounting tension is reduced to 1/4 T ₀ due to use, when the driving pulley is rotated over the entire rotation speed range X, the CPU 15 issues a warning, whereby the user properly determines the replacement time. can do.

As described above, in the present embodiment, the measurement speed region in X, the effective rotational phase difference de at a certain speed, whether it is within the allowable range de _r that is set in advance for each rotational speed By determining, the replacement time can be determined.

  In the third embodiment of the present invention, as in the second embodiment, de = f (n) is calculated from the effective tension and the rotational speed stored in the memory, and the function f (n) is The replacement time may be determined by determining whether or not it is within the allowable region β.

  Furthermore, in the first to third embodiments, the case where the load fluctuation occurs and the torque fluctuates periodically according to the rotation is described. However, the present system similarly applies to the case where the load fluctuation does not occur. Can be applied. If no load fluctuation occurs, the torque Tr is applied in one direction as shown in FIG. 10, so that torque Tr = effective tension Te. Similarly, since the rotational phase difference is also generated in one direction according to the torque Tr, the effective rotational phase difference de = the rotational phase difference d.

  In the third embodiment according to the present invention, the rotational phase difference d is indicated by a length on the pitch line, but may be indicated by an angular difference of the driven pulley 11 with respect to the driving pulley 10.

The rotational phase difference d may be indicated by a difference (speed difference) v between the rotational speeds of the driven pulley and the driving pulley. The speed difference v is the rotational phase difference d per unit time, and periodically changes in accordance with the rotational phase difference d as shown in FIG. 11, so that the speed difference v also varies with the rotational speed as shown in FIG. Change. Therefore, the maximum value v _{max of the} speed difference may be used as the effective speed difference ve, and the effective speed difference ve may be used instead of the effective rotation phase difference de in the third embodiment. In this case, the allowable range ve _r is set from the effective velocity difference ve.

In the first and second embodiments of the present invention, the effective tension Te is obtained from the maximum torque value Tr _max, but may be obtained from the absolute value of the minimum torque value Tr _min . Furthermore, it may be obtained from the average value of Tr _max and the absolute value of Tr _min . Similarly, the effective rotational phase difference de may be obtained from the absolute value of the minimum value d _min . Further, it may be obtained from an average value of d _max and the absolute value of d _min . The same applies to the effective speed difference ve.

Further, in this embodiment, the allowable range Te _r or the like according to the rotation speed of the driving pulley 10 is set, it may be set according to the rotation speed of the toothed belt 12 or the driven pulley 11. Further, although the torque of the driving pulley 10 is measured, the torque of the driven pulley may be measured.

  In the present embodiment, the belt replacement time is determined based on the effective tension Te or the effective rotational phase difference de. However, if the belt replacement time changes in accordance with the load torque, it is based on other measured values. It may be discriminated.

  In the first to third embodiments described above, specific numerical values of the rotational phase difference and the effective tension are schematic numerical values, and thus the units are omitted.

1 is a schematic diagram of a belt replacement time determination system according to a first embodiment of the present invention. The torque displacement measured by a strain gauge is shown. The allowable range is schematically shown with the vertical axis representing the effective tension and the horizontal axis representing the rotational speed. A method for setting an allowable area is schematically shown. A method for determining the belt replacement time in the second embodiment is schematically shown. The schematic of the belt replacement time discrimination | determination system in 3rd Embodiment is shown. The relationship between a torque and a rotation phase difference is shown typically. The allowable range is schematically shown where the vertical axis represents the effective rotational phase difference and the horizontal axis represents the rotational speed. A method for setting an allowable area is schematically shown. The relationship between the torque and the rotation phase difference when no load fluctuation occurs is schematically shown. A relationship among torque, rotational phase difference, and speed difference is schematically shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Drive pulley 11 Drive pulley 12 Toothed belt 14 Strain gauge 24, 25 Rotational speed detector X Measurement rotational speed range α, β Allowable range

Claims (8)

A belt replacement time determination system for determining a replacement time of a transmission belt wound around a pulley,
While the pulley is rotated over the predetermined rotation speed range, a plurality of speed measuring means for measuring a measurement value that varies in conjunction with the load torque acting on the pulley,
A rotational speed detecting means for detecting the rotational speed of the pulley when the measured value is measured;
It is determined whether or not the measured value falls within a preset allowable range within the rotation speed range, and when it is determined that the measured value is not within the allowable range, it is determined that it is time to replace the transmission belt. A discrimination means ,
The transmission belt is wound around a driven and driven pulley, the measured value is an effective tension or a rotational phase difference of the driven pulley relative to the driven pulley, and the allowable range is determined for each rotation speed,
The discriminating means determines whether or not each of the measured values measured at each rotational speed falls within the allowable range determined for each rotational speed .   The measurement means measures the measurement values for a plurality of rotation speeds, and calculates and approximates the measurement values at each rotation speed that is not measured from the respective measurement values, and the discrimination means calculates the approximation. The belt replacement time determination system according to claim 1, wherein whether or not the measured value is within the allowable range is determined. The belt replacement time determination system according to claim 1 , wherein the rotational phase difference is a difference in rotational speed between the driving pulley and the driven pulley.   The transmission belt is attached to the pulley with a standard attachment tension, and the measured value measured at each rotational speed while the pulley is rotated over the entire predetermined rotational speed range is used as a reference value, and the allowable range. Is set based on the reference value, and the belt replacement time determination system according to claim 1. The belt replacement time determination system according to claim 4 , wherein the allowable range is set around the reference value. A belt replacement time determination system for determining a replacement time of a transmission belt wound around a pulley,
While the pulley is rotated over the predetermined rotation speed range, a plurality of speed measuring means for measuring a measurement value that varies in conjunction with the load torque acting on the pulley,
A rotational speed detecting means for detecting the rotational speed of the pulley when the measured value is measured;
Calculating means for obtaining a function indicating a relationship between the plurality of measured values measured and the rotation speed when each measured value is measured;
It is determined whether or not the function falls within an allowable range of the measurement value determined according to the rotational speed, and when it is determined that the function is not within the allowable range, it is determined that it is time to replace the transmission belt. and a discriminating means for,
A belt replacement timing determination system, wherein the transmission belt is wound around a driven and driven pulley, and the measured value is an effective tension or a rotational phase difference of the driven pulley with respect to the driven pulley . A belt replacement time determination method for determining the replacement time of a transmission belt wound around a pulley,
While the pulley is rotated over the predetermined rotation speed range, the plurality of rotation speed, a measurement step of measuring a measurement value that varies in conjunction with the load torque acting on the pulley,
A rotational speed detection step of detecting the rotational speed of the pulley when the measured value is measured;
It is determined whether or not the measured value falls within a preset allowable range within the rotation speed range, and when it is determined that the measured value is not within the allowable range, it is determined that it is time to replace the transmission belt. A determination step ,
The transmission belt is wound around a driven and driven pulley, the measured value is an effective tension or a rotational phase difference of the driven pulley relative to the driven pulley, and the allowable range is determined for each rotation speed. ,
Wherein in the determination step, each measured the measured values at each rpm, the belt replacement timing determination method characterized by determining whether or not to enter into the allowable range set for each of the rotational speed. A belt replacement time determination method for determining the replacement time of a transmission belt wound around a pulley,
While the pulley is rotated over the predetermined rotation speed range, the plurality of rotation speed, a measurement step of measuring a measurement value that varies in conjunction with the load torque acting on the pulley,
A rotational speed detection step of detecting the rotational speed of the pulley when the measured value is measured;
A calculation step for obtaining a function indicating a relationship between the measured plurality of measured values and the rotation speed when each measured value is measured;
It is determined whether or not the function falls within an allowable range of the measurement value determined according to the rotational speed, and when it is determined that the function is not within the allowable range, it is determined that it is time to replace the transmission belt. for example Bei and determining step of,
The transmission belt has been wound around the driven and driving pulleys, belt replacement timing determination how to wherein the measurement value is the rotational phase difference of the driven pulley to the effective tension or the driving pulley.

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