Belt characteristic measuring device, belt characteristic measuring method, and program

Abstract

To measure an accurate resonance frequency and belt tension with little change in rigidity or resonance frequency of a resonance portion of a belt wound around pulleys in a stationary state.SOLUTION: An information processing device 10 includes: a piezoelectric element 15 attachable to a toothed belt 1 wound around a drive pulley DR and a driven pulley DN or attachable to one of the drive pulley DR or the driven pulley DN; a control unit 11 configured to calculate the resonance frequency F of the toothed belt 1 based on a voltage generated by the piezoelectric effect of the piezoelectric element 15 when the toothed belt 1 is vibrated in a stationary state in which the drive pulley DR and the driven pulley DN are held stationary without making rotations; and a display unit 14 configured to display the resonance frequency F calculated by the control unit 11.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an apparatus and method for measuring belt characteristics of a belt wound between stationary pulleys, and a program for measuring belt characteristics. [Background technology]

[0002] When using a transmission belt or conveyor belt wound between pulleys, it is necessary to apply an appropriate tension to the belt. One known method for calculating belt tension, which is one of the belt characteristics, is to measure and use the resonance frequency, which is also a belt characteristic. The following relationship holds between tension and resonance frequency.

[0003] T=W(2LF) 2 T: Tension (N) W: Mass per unit length (kg / m) L: Length of the resonating part (m) F: Resonance frequency (Hz)

[0004] Therefore, by measuring the resonance frequency while the pulleys are stationary and not rotating, and combining this with the conditions of the mass per unit length (unit mass) and the length of the resonance part (span length: the distance between the contact points of each pulley and the belt), it is possible to determine the belt tension. Various methods and devices have been proposed that make it possible to measure the resonance frequency and perform various calculations as a series of operations.

[0005] For example, Patent Document 1 discloses a tension measuring instrument that includes a sound wave detection means for detecting sound waves generated by vibrations of a tensioned object, a frequency analysis means for performing frequency analysis of the detection results of the sound wave detection means, and a tension calculation means for calculating the tension of the tensioned object from the natural frequency of the sound waves determined by the frequency analysis means. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Utility Model Application Publication No. 62-12832 [Patent Document 2] International Publication No. 2014 / 091713 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0007] However, this method using sound waves has the problem that it is difficult to measure in an environment where there is noise other than sound waves generated by the vibration of the belt being measured. Therefore, attempts are being made to measure the resonance frequency using methods other than sound waves.

[0008] For example, Patent Document 2 discloses a method for measuring the natural frequency by attaching an acceleration sensor that detects acceleration due to belt vibration to a resonating portion of the belt. Examples of acceleration sensors include MEMS acceleration sensors that use capacitance detection methods and MEMS acceleration sensors that use piezoresistive methods, and states that MEMS acceleration sensors that use capacitance detection methods are preferred.

[0009] Although the method disclosed in Patent Document 2 has the effect of being immune to noise, it is necessary to attach a relatively large acceleration sensor to the resonating part of the belt, which requires correction of the acceleration sensor's mass. Also, because the acceleration sensor is attached to the resonating part of the belt, the stiffness of the resonating part changes, which can make it impossible to measure the resonance frequency accurately.

[0010] Therefore, an object of the present invention is to accurately measure the resonance frequency and belt tension without substantially changing the stiffness and resonance frequency of the resonating portion of the belt wound between stationary pulleys. [Means for solving the problem]

[0011] The present invention provides a piezoelectric element that can be attached to a belt wound around pulleys or the pulleys; a control unit that calculates a resonance frequency of the belt based on a voltage generated by a piezoelectric effect of the piezoelectric element when the belt is vibrated in a stationary state in which the pulley is kept stationary so as not to rotate; and a display unit that displays the resonance frequency calculated by the control unit.

[0012] In the above configuration, the piezoelectric element has a simpler structure and a smaller mass than the MEMS acceleration sensor of Patent Document 2, and therefore can be easily attached to the belt wound between the pulleys or to the pulleys themselves. Furthermore, even when attached to the resonating portion of the belt (the belt span length portion), the stiffness and resonant frequency of the resonating portion are hardly changed, and an accurate resonant frequency can be measured. The control unit calculates the resonant frequency of the belt based on the voltage of the piezoelectric element when the belt is vibrated, and may calculate the resonant frequency of the belt when the belt is vibrated, or may calculate the resonant frequency of the belt after the belt is vibrated.

[0013] The present invention also provides a piezoelectric element that can be attached to a belt wound around pulleys or the pulleys, a storage unit capable of storing the mass per unit length of the belt and the span length, which is the actual distance between the contact points of each pulley and the belt; a control unit that calculates the tension of the belt based on the mass per unit length of the belt and the span length stored in the storage unit, and a resonance frequency of the belt calculated based on a voltage generated by the piezoelectric effect of the piezoelectric element when the belt is vibrated in a stationary state in which the pulley is stationary so as not to rotate; and a display unit that displays the tension of the belt calculated by the control unit.

[0014] In the above configuration, the piezoelectric element has a simpler structure and a smaller mass than the MEMS acceleration sensor of Patent Document 2, and therefore can be easily attached to the belt wound between the pulleys or to the pulleys themselves. Furthermore, even when attached to the resonating portion of the belt (the span length portion of the belt), an accurate resonant frequency can be calculated without substantially changing the stiffness or resonant frequency of the resonating portion, and the tension of the belt can be measured based on the calculated resonant frequency, as well as the mass per unit length of the belt and the span length, which are stored in advance in a memory unit.

[0015] Further, the present invention provides the belt characteristic measuring device, At least a part of the piezoelectric element may be attached to a winding portion of the belt, which is a portion of the belt that is wound around the pulley.

[0016] Since piezoelectric elements can detect even minute vibrations, they can be attached to the wrapping portion (the portion of the belt excluding the span length portion where the belt is wrapped around the pulley) other than the resonating portion (span length portion) of the belt, and the voltage generated by the piezoelectric effect can be measured. By attaching the piezoelectric element to the winding portion, the mass and rigidity of the resonating portion of the belt are not changed, allowing the resonant frequency of the belt to be measured more accurately. The piezoelectric element may be attached so that the entirety of it is disposed on the winding portion, or so that only a part of it is disposed on the winding portion.

[0017] Further, the present invention provides the belt characteristic measuring device, At least a portion of the piezoelectric element may be attached at a position on the winding portion where the belt begins to wind around the pulley, with the central angle from the base point being within a range of 0 to 50 degrees, with the center of rotation of the pulley as the center point.

[0018] According to the above configuration, when the belt wound between the pulleys is vibrated, the vibrations are not absorbed by the pulleys but reach the piezoelectric element at a level that allows the piezoelectric effect of the piezoelectric element to be fully exerted, thereby making it possible to measure the resonant frequency of the belt more reliably. The piezoelectric elements may be attached so that all of them are positioned within a central angle range of 0 to 50 degrees from the base point of the winding portion, or some of them may be attached so that they are positioned within a central angle range of 0 to 50 degrees from the base point of the winding portion.

[0019] Further, the present invention provides the belt characteristic measuring device, At least a part of the piezoelectric element may be attached to a side surface of the pulley between a winding portion where the belt is wound around the pulley and the center of rotation of the pulley.

[0020] According to the above configuration, the mass and rigidity of the resonating portion of the belt are not changed by attaching the piezoelectric element to the side of the pulley, so the resonant frequency of the belt can be measured with higher accuracy. The piezoelectric element may be attached so that the entire element is positioned on the side of the pulley between the winding portion and the center of rotation of the pulley, or so that a portion of the element is positioned on the side of the pulley between the winding portion and the center of rotation of the pulley.

[0021] Further, the present invention provides the belt characteristic measuring device, At least a part of the piezoelectric element may be attached at a position where the central angle from the base point where the belt starts to wrap around the pulley is within a range of 0 to 50 degrees with the center of rotation of the pulley as the center point.

[0022] According to the above configuration, when the belt wound between the pulleys is vibrated, the vibrations are not absorbed by the pulleys but reach the piezoelectric element at a level that allows the piezoelectric effect of the piezoelectric element to be fully exerted, thereby making it possible to measure the resonant frequency of the belt more reliably. The piezoelectric element may be attached so that all of it is positioned on the side of the pulley between the part of the winding portion that is within a central angle of 0 to 50 degrees from the base point and the center of rotation of the pulley, or part of it is attached so that it is positioned on the side of the pulley between the part of the winding portion that is within a central angle of 0 to 50 degrees from the base point and the center of rotation of the pulley.

[0023] The present invention also provides (1a) A step in which the control unit calculates a resonance frequency of the belt based on a voltage generated by the piezoelectric effect of the belt wound between the pulleys or a piezoelectric element attached to the pulleys when the belt wound between the pulleys is vibrated while the pulleys are kept stationary so as not to rotate; (1b) A belt characteristic measuring method, in which the control unit executes a step of displaying the resonance frequency calculated in the step (1a) on a display unit.

[0024] The present invention also provides (2a) A step in which the control unit calculates a resonance frequency of the belt, which is calculated based on a voltage generated by the piezoelectric effect of the belt wound between the pulleys or a piezoelectric element attached to the pulleys when the belt wound between the pulleys is vibrated while the pulleys are kept stationary so as not to rotate, and calculates the tension of the belt based on the mass per unit length of the belt and the span length, which is the actual distance between the contact points of each pulley and the belt, which are stored in a memory unit; (2b) A belt characteristic measuring method, in which the control unit executes a step of displaying the tension of the belt calculated in the step (2a) on a display unit.

[0025] Further, the present invention provides the belt characteristic measuring method, At least a part of the piezoelectric element may be attached to a winding portion of the belt, which is a portion of the belt that is wound around the pulley.

[0026] Further, the present invention provides the belt characteristic measuring method, At least a part of the piezoelectric element may be attached at a position where the central angle from the base point where the belt starts to wrap around the pulley is within a range of 0 to 50 degrees with the center of rotation of the pulley as the center point.

[0027] Further, the present invention provides the belt characteristic measuring method, At least a part of the piezoelectric element may be attached to a side surface of the pulley between a winding portion where the belt is wound around the pulley and the center of rotation of the pulley.

[0028] Further, the present invention provides the belt characteristic measuring method, At least a part of the piezoelectric element may be attached at a position where the central angle from the base point where the belt starts to wrap around the pulley is within a range of 0 to 50 degrees with the center of rotation of the pulley as the center point.

[0029] The present invention also provides a program for causing a computer to display the resonance frequency of a belt wound between pulleys, the program comprising: On the computer, (3a) A process of calculating a resonance frequency of the belt based on a voltage generated by the piezoelectric effect of the belt wound between the pulleys or a piezoelectric element attached to the pulleys when the belt wound between the pulleys is vibrated in a stationary state with the pulleys stationary so as not to rotate; (3b) A program for executing a process of displaying the resonance frequency calculated by the process of (3a) on a display unit.

[0030] The present invention also provides a program for causing a computer to display tension of a belt wound between pulleys, the program comprising: On the computer, (4a) A process of calculating the tension of the belt based on the resonant frequency of the belt, which is calculated based on the voltage generated by the piezoelectric effect of the belt wound between the pulleys or the piezoelectric element attached to the pulleys when the belt wound between the pulleys is vibrated in a stationary state with the pulleys stationary so as not to rotate, and based on the mass per unit length of the belt and the span length, which is the actual distance between the contact points of each pulley and the belt, stored in a memory unit; (4b) A program for executing a process of displaying the tension of the belt calculated by the process of (4a) on a display unit.

[0031] Furthermore, the present invention provides the above-mentioned program, At least a part of the piezoelectric element may be attached to a winding portion of the belt, which is a portion of the belt that is wound around the pulley.

[0032] Furthermore, the present invention provides the above-mentioned program, At least a part of the piezoelectric element may be attached at a position where the central angle from the base point where the belt starts to wrap around the pulley is within a range of 0 to 50 degrees with the center of rotation of the pulley as the center point.

[0033] Furthermore, the present invention provides the above-mentioned program, At least a part of the piezoelectric element may be attached to a side surface of the pulley between a winding portion where the belt is wound around the pulley and the center of rotation of the pulley.

[0034] Furthermore, the present invention provides the above-mentioned program, At least a part of the piezoelectric element may be attached at a position where the central angle from the base point where the belt starts to wrap around the pulley is within a range of 0 to 50 degrees with the center of rotation of the pulley as the center point. [Effects of the Invention]

[0035] It is possible to measure the accurate resonance frequency and belt tension without substantially changing the stiffness or resonance frequency of the resonating portion of the belt wound between the pulleys. [Brief explanation of the drawings]

[0036] [Figure 1] 1 is a schematic explanatory diagram of a power transmission mechanism in which a toothed belt is wound between a driving pulley and a driven pulley, and an information processing device according to an embodiment of the present invention; [Figure 2] FIG. 1 is a perspective view of a piezoelectric element according to an embodiment of the present invention. [Figure 3] 1A and 1B are explanatory diagrams of a piezoelectric element according to an embodiment of the present invention. [Figure 4] FIG. 3 is an explanatory diagram of the arrangement position of the piezoelectric element according to the first embodiment. [Figure 5] 10 is a graph of the power spectrum when a piezoelectric element is attached at position A in the toothed belt according to Example 1 and measurement is performed. [Figure 6] 10 is a graph of a power spectrum measured when a piezoelectric element is attached at position A in the coupled V-belt according to Example 2. [Figure 7] FIG. 10 is an explanatory diagram of the arrangement position of the piezoelectric element according to the third embodiment. [Figure 8] 10 is a graph of the power spectrum when measurements are taken with piezoelectric elements attached to positions E to G in the toothed belt according to Example 3. [Figure 9] FIG. 10 is an explanatory diagram of the arrangement position of the piezoelectric element according to the fourth embodiment. [Figure 10] 10 is a graph of a time axis waveform measured when a piezoelectric element is attached at a position I and a position K in Example 4. [Figure 11] 10 is a graph of a time axis waveform measured when a piezoelectric element is attached at a position M and a position O in Example 4. [Figure 12] 10 is a graph showing power spectra measured when piezoelectric elements are attached at positions I and K in Example 4. [Figure 13] 10 is a graph showing power spectra measured when piezoelectric elements are attached at positions M and O in Example 4. BEST MODE FOR CARRYING OUT THE INVENTION

[0037] (Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, an information processing device 10 (corresponding to a belt characteristic measuring device) will be described as an example, which measures the resonant frequency F and tension T of a toothed belt 1 (belt) wound between a driving pulley DR and a driven pulley DN in a stationary state, as the belt characteristics of the toothed belt 1, as shown in FIG.

[0038] As shown in Figure 1, the toothed belt 1 is used by being wound around a drive pulley DR connected to a drive rotating shaft and a driven pulley DN connected to a driven rotating shaft. As a result, when the drive rotating shaft rotates, the drive pulley DR rotates, and this rotational motion is transmitted to the driven pulley DN via the toothed belt 1, causing the driven rotating shaft to rotate and transmitting power.

[0039] (Toothed belt 1) The toothed belt 1 has an annular belt shape, and teeth (not shown) are arranged at predetermined intervals on the inner circumference along the longitudinal direction (circumferential direction) of the belt. In this embodiment, the measurement of the resonance frequency and tension of the toothed belt 1 is illustrated, but the resonance frequency and tension of various types of transmission belts (V-belts, V-ribbed belts, flat belts), conveyor belts, etc. may also be measured.

[0040] (Drive pulley DR and driven pulley DN) Tooth grooves (not shown) that correspond to the teeth of the toothed belt 1 are provided at predetermined intervals on the outer periphery of the drive pulley DR. Tooth grooves (not shown) that correspond to the teeth of the toothed belt 1 are also provided at predetermined intervals on the outer periphery of the driven pulley DN.

[0041] (Information processing device 10) 1, the information processing device 10 is a terminal device (a dedicated terminal device connectable to a personal computer, a smartphone, a tablet, etc.) that measures the resonance frequency and tension of the toothed belt 1, and can be operated by a user to input various data and requests, store and save data, and perform calculations. The information processing device 10 of this embodiment includes a control unit 11, a storage unit 12, an input unit 13, and a display unit 14, and is further connected to a piezoelectric element 15.

[0042] The control unit 11 controls the computer in the information processing device 10 (CPU, etc.). The storage unit 12 is configured by a ROM (Read Only Memory) in which a system program is stored, a RAM (Random Access Memory) which is a rewritable storage area, a flash memory, etc. (details will be described later). The input unit 13 is an operating device for users to input various types of data, requests, and commands. The display unit 14 displays the calculated resonance frequency of the toothed belt 1, the tension of the toothed belt 1, information based on commands from the control unit 11, and the like. The piezoelectric element 15 is attached to the toothed belt 1, the driving pulley DR, or the driven pulley DN, and is an element that produces a piezoelectric effect when the toothed belt 1 is vibrated (details will be described later).

[0043] The information processing device 10 may also include an amplifier that amplifies the voltage signal (electrical signal) from the piezoelectric element 15, and a filter (such as a low-pass filter or a high-pass filter) that extracts only signals in a specific frequency range.

[0044] (Piezoelectric element 15) The piezoelectric element 15 has a structure in which a piezoelectric body that exhibits the piezoelectric effect (the phenomenon in which a voltage is generated when pressure is applied) is sandwiched between electrodes.

[0045] For example, as shown in Figures 2 and 3(A), the piezoelectric element 15 has a structure in which a piezoelectric body 151 made of quartz, ceramics, PVDF (polyvinylidene fluoride), or the like and having a thickness of about several tens of micrometers is sandwiched between a metal vapor deposition film (conductive film) 152 having a thickness of about several micrometers and a conductive metal plate 153 having a thickness of about several hundred micrometers, and the overall thickness of the piezoelectric element 15 is about 1 mm, making it small and lightweight. Furthermore, the piezoelectric body 151, the metal vapor deposition film 152, and the conductive metal plate 153 are all circular, and the conductive metal plate 153 is larger than the piezoelectric body 151. This allows the respective conductors connected to the metal vapor deposition film 152 and the conductive metal plate 153 to be positioned on the upper side, making it easy to attach to the toothed belt 1 or the like.

[0046] 3(B), the piezoelectric element 15 may have a structure in which a piezoelectric body 251 is sandwiched between a metal vapor deposition film (conductive film) 252 having a thickness of about several μm and a metal vapor deposition film (conductive film) 253 having a thickness of about several μm provided on a substrate 254. In this case, the piezoelectric body 251, the metal vapor deposition film 252, and the metal vapor deposition film 253 provided on the substrate 254 are also circular, and the metal vapor deposition film 253 provided on the substrate 254 is larger than the piezoelectric body 251.

[0047] As shown in FIG. 3(C), the piezoelectric element 15 may have a structure in which a piezoelectric body 351 is sandwiched between a metal vapor deposition film (conductive film) 352 and a metal vapor deposition film (conductive film) 353 each having a thickness of about several μm.

[0048] Furthermore, when attaching the piezoelectric element 15 to the toothed belt 1 or the drive pulley DR or driven pulley DN, adhesive tape is applied to the back of the piezoelectric element 15, and the piezoelectric element 15 is attached to either the toothed belt 1, the drive pulley DR, or the driven pulley DN (see Figure 1). As such, since the piezoelectric element 15 is attached to a toothed belt 1 or the like each time it is used, it is preferable that the electrode on the back side of the piezoelectric element 15 be formed from a conductive metal plate 153 with a certain thickness and strength as shown in Figure 3(A), or from a metal vapor deposition film 253 provided on a substrate 254 as shown in Figure 3(B).

[0049] (Storage unit 12) The memory unit 12 stores the mass W per unit length of the toothed belt 1 and the actual span length S (see Figure 1), which is the distance between the contact point between the drive pulley DR and the toothed belt 1 and the contact point between the driven pulley DN and the toothed belt 1, via the input unit 13, etc. The span length S is determined by the relationship between tension T and resonance frequency F: T=W(2LF) 2 However, in this embodiment, calculations are performed assuming that the span length S is the length L of the resonating portion (S≈L).

[0050] The memory unit 12 also stores a program for analyzing the voltage signal sent from the piezoelectric element 15 (for example, FFT analysis: fast Fourier transform) to calculate the resonance frequency of the toothed belt 1, a program for calculating the tension of the toothed belt 1, and the like.

[0051] The program for calculating the tension T of the toothed belt 1 is as follows: T = W(2LF) where S is the span length of the actual toothed belt 1, L is the length of the resonating part, W is the mass per unit length of the toothed belt 1, and F is the resonant frequency of the toothed belt 1 calculated by analyzing the voltage signal sent from the piezoelectric element 15. 2 Substitute this into the equation to calculate the tension T of the toothed belt 1.

[0052] (Measurement process of resonance frequency F and tension T of toothed belt 1) Next, a process for measuring the resonance frequency F and tension T of the toothed belt 1 using the information processing device 10 will be described.

[0053] (1) Install toothed belt 1 between the pulleys First, the user loops the toothed belt 1 between the drive pulley DR and the driven pulley DN.

[0054] (2) Installation of the piezoelectric element 15 Next, the user attaches the piezoelectric element 15 to the toothed belt 1 wound between the drive pulley DR and the driven pulley DN, or to the drive pulley DR or the driven pulley DN, using adhesive tape.

[0055] (2-1) Here, the piezoelectric element 15 may be attached to the outer circumferential surface of the resonating portion of the toothed belt 1 corresponding to the span length S, as shown in FIG. When the toothed belt 1, wound between the drive pulley DR and the driven pulley DN, is vibrated by hitting the vicinity of the center BC of the toothed belt 1 (see Figure 1) with a metal rod, the vibration of the resonating part is large, so a large voltage is likely to be generated.In addition, because the piezoelectric element 15 is lightweight, even when it is attached to the resonating part of the toothed belt 1, its effect on the mass and rigidity of the toothed belt 1 is small.

[0056] (2-2) In addition, at least a portion of the piezoelectric element 15 may be attached to the outer surface of the winding portion R (see Figure 1), which is the portion of the toothed belt 1 where the toothed belt 1 is wound around the drive pulley DR, or to the outer surface of the winding portion N (see Figure 1), which is the portion of the toothed belt 1 where the toothed belt 1 is wound around the driven pulley DN.

[0057] Since the piezoelectric element 15 can detect even minute vibrations, at least a portion of the piezoelectric element 15 can be attached to the winding portion R or N other than the resonating portion (span length S portion) of the toothed belt 1, and the voltage generated by the piezoelectric effect can be measured. By attaching the piezoelectric element 15 to the winding portion R or N, the mass and rigidity of the resonating portion of the toothed belt 1 are not changed, so the resonant frequency F of the toothed belt 1 can be measured more accurately.

[0058] Furthermore, assuming that the toothed belt 1 is vibrated by hitting the vicinity of the center BC (see Figure 1) of the toothed belt 1 wound between the drive pulley DR and the driven pulley DN with a metal rod, when attaching the piezoelectric element 15 to the winding portion R, it is preferable that the piezoelectric element 15 be attached at a position in the winding portion R where the position where the toothed belt 1 begins to wind around the drive pulley DR is set as the base point RS, and the central point is the rotation center RC of the drive pulley DR, and the central point is within the range of 0 to 50 degrees from the base point RS. Similarly, when attaching the piezoelectric element 15 to the winding portion N, it is preferable that the piezoelectric element 15 be attached at a position on the winding portion N where the toothed belt 1 begins to wind around the driven pulley DN as the base point NS, with the central angle from the base point NS being within a range of 0 to 50 degrees, with the rotation center NC of the driven pulley DN as the center point. According to the above configuration, when the toothed belt 1 wound between the drive pulley DR and the driven pulley DN is vibrated, the vibrations are not absorbed by the drive pulley DR and the driven pulley DN, but reach the piezoelectric element 15 to an extent that the piezoelectric effect of the piezoelectric element 15 is fully exerted, so that the resonant frequency F of the toothed belt 1 can be measured more reliably.

[0059] (2-3) At least a portion of the piezoelectric element 15 may be attached to the side of the drive pulley DR between the winding portion R where the toothed belt 1 is wound around the drive pulley DR and the rotation center RC of the drive pulley DR (see Figure 1). At least a portion of the piezoelectric element 15 may be attached to the side surface of the drive pulley DR between the outer periphery of the drive pulley DR where the toothed belt 1 is not wrapped around the drive pulley DR and the center of rotation RC of the drive pulley DR. Furthermore, at least a part of the piezoelectric element 15 may be attached to the side surface of the driven pulley DN between the winding portion N where the toothed belt 1 is wound around the driven pulley DN and the rotation center NC of the driven pulley DN. At least a portion of the piezoelectric element 15 may be attached to the side surface of the driven pulley DN between the outer circumferential edge of the driven pulley DN where the toothed belt 1 is not wrapped around the driven pulley DN and the rotation center NC of the driven pulley DN.

[0060] Since the piezoelectric element 15 can detect even minute vibrations, the piezoelectric element 15 can be attached to the side surface of the driving pulley DR or the side surface of the driven pulley DN to measure the voltage generated by the piezoelectric effect. By attaching the piezoelectric element 15 to the side of the drive pulley DR or the side of the driven pulley DN, the mass and rigidity of the resonating part of the toothed belt 1 are not changed, so the resonant frequency F of the toothed belt 1 can be measured more accurately.

[0061] Furthermore, assuming that the toothed belt 1 is vibrated by hitting the vicinity of the center BC (see Figure 1) of the toothed belt 1 wound between the drive pulley DR and the driven pulley DN with a metal rod, when the piezoelectric element 15 is attached on the side of the drive pulley DR between the winding portion R and the rotation center RC of the drive pulley DR, it is preferable that at least a portion of the piezoelectric element 15 is attached at a position within a central angle of 0 to 50 degrees from the base point RS, with the position where the toothed belt 1 begins to wind around the drive pulley DR as the base point RS and the rotation center RC of the drive pulley DR as the center point. Similarly, when the piezoelectric element 15 is attached to the side of the driven pulley DN between the winding portion N and the rotation center NC of the driven pulley DN, it is preferable that at least a portion of the piezoelectric element 15 is attached at a position where the central angle from the base point NS, which is the position where the toothed belt 1 begins to wind around the driven pulley DN, is within a range of 0 to 50 degrees, with the rotation center NC of the driven pulley DN as the center point. According to the above configuration, when the toothed belt 1 wound between the drive pulley DR and the driven pulley DN is vibrated, the vibrations are not absorbed by the drive pulley DR and the driven pulley DN, but reach the piezoelectric element 15 to an extent that the piezoelectric effect of the piezoelectric element 15 is fully exerted, so that the resonant frequency F of the toothed belt 1 can be measured more reliably.

[0062] When the piezoelectric element 15 is attached to the side surface of the drive pulley DR, it is preferable to attach it closer to the outer periphery of the drive pulley DR than to the center of rotation RC of the drive pulley DR. For example, the piezoelectric element 15 may be attached to the outer periphery of the side surface of the drive pulley DR. Similarly, when the piezoelectric element 15 is attached to the side surface of the driven pulley DN, it is preferable to attach it closer to the outer periphery of the driven pulley DN than to the center of rotation NC of the driven pulley DN. For example, the piezoelectric element 15 may be attached to the outer periphery of the side surface of the driven pulley DN.

[0063] (3) Measurement of the resonance frequency F of toothed belt 1 Next, the user wraps the toothed belt 1 between the drive pulley DR and the driven pulley DN. Then, while the drive pulley DR and the driven pulley DN are stationary and not rotating, a physical impact is applied to the toothed belt 1 near the center BC, causing the toothed belt 1 to vibrate. The vibrations generated at this time vibrate the piezoelectric element 15, and pressure is applied to the piezoelectric body 151, generating a voltage between the metal deposition film 152 and the conductive metal plate 153 (between the two electrodes). The control unit 11 of the information processing device 10 receives a signal of this generated voltage and analyzes the voltage change to determine the resonant frequency F of the toothed belt 1. Specifically, conductors are attached to the metal deposition film 152 and the conductive metal plate 153 of the piezoelectric element 15, and the control unit 11 of the information processing device 10 analyzes the generated voltage using an FFT analyzer or the like, plots the power spectrum of the frequency-axis waveform, and calculates the frequency showing the strongest peak as the resonant frequency F.

[0064] (4) Resonance frequency F of toothed belt 1 Next, the resonance frequency F of the toothed belt 1 calculated by the control unit 11 is displayed on the display unit 14.

[0065] (5) Calculation of tension T of toothed belt 1 Next, the control unit 11 calculates the mass W per unit length of the toothed belt 1, the span length S (span length S≈length L of the resonating portion of the toothed belt 1), and the calculated resonance frequency F of the toothed belt 1, which are stored in advance in the storage unit 12 by the input unit 13 or the like, as follows: T=W(2LF) 2 Substitute this into the equation to calculate the tension T of the toothed belt 1.

[0066] (6) Display of tension T of toothed belt 1 Next, the tension T of the toothed belt 1 calculated by the control unit 11 is displayed on the display unit 14.

[0067] In addition, the user may independently perform the operation of measuring the resonance frequency F (process (3)) multiple times (for example, five times) by physically applying an impact near the center BC of the toothed belt 1, which is wound between the drive pulley DR and the driven pulley DN and in a stationary state, to vibrate the toothed belt 1, and generating a voltage in the piezoelectric element 15 due to the vibration generated at that time. In this case, the user may calculate an average of the tension T of the toothed belt 1 calculated based on the calculated resonance frequency F for multiple times and display it on the display unit 14. In other words, the average of the tension T of the toothed belt 1 calculated for multiple previous times can be calculated. In this way, if the measured values ​​for the past multiple times are stable, it can be determined that the measurements have been performed normally, and the measurement accuracy of the tension T of the toothed belt 1 can be improved.

[0068] The control unit 11 may also determine whether the calculated tension T of the toothed belt 1 is within an appropriate range that indicates an appropriate value of the tension T of the toothed belt 1 and that is stored in advance in the storage unit. If the calculated tension T is within the appropriate range, the display unit 14 may display a message or the like indicating that the tension T is appropriate. On the other hand, if the calculated tension T exceeds the upper limit of the appropriate range, the display unit 14 may display a message or the like indicating that the tension T is too high, and if the calculated tension T is below the lower limit of the appropriate range, the display unit 14 may display a message or the like indicating that the tension T is too low.

[0069] According to the information processing device 10, the piezoelectric element 15 has a simpler structure and a smaller mass than the MEMS-type acceleration sensor of Patent Document 2, and therefore can be easily attached to the toothed belt 1 wound between the drive pulley DR and the driven pulley DN or to the drive pulley DR itself (the driven pulley DN itself). Even when the piezoelectric element 15 is attached to the resonating portion of the toothed belt 1 (the portion with span length S of the toothed belt 1), the resonating frequency F can be accurately calculated (measured) without substantially changing the stiffness of the resonating portion or the resonating frequency F. Furthermore, the tension T of the toothed belt 1 can be calculated (measured) based on the calculated resonating frequency F, the mass W per unit length of the toothed belt 1, and the span length S (span length S ≈ length L of the resonating portion) that are stored in advance in the storage unit 12.

[0070] (Other embodiments) The process of measuring the tension T of the toothed belt 1 or the like, which is executed in the above embodiment, may be installed as software (program, data) and executed in an information processing device, exemplified by a portable information device such as a smartphone, a portable computer, a laptop computer, a notebook computer, a tablet PC, a handheld PC, a PDA (Personal Data Assistant), etc. In this case, the software may be downloaded from a server or the like via communication means and stored in a storage device (flash memory, etc.) within the portable information device. The communication means may be a transmission path that allows two-way communication, such as the Internet or cable television, or may be broadcasting that transmits information in only one direction.

[0071] In addition, software (program) that executes the process of measuring the tension T of the toothed belt 1 or the like may be stored in a storage medium such as a CD-ROM, DVD-ROM, MO (magneto-optical disk), hard disk, or flash memory, and may be read from the storage medium as needed and installed in the memory unit 12 of the information processing device 10.

[0072] Furthermore, the contents described in the above embodiment may be implemented as a service executed between an information terminal such as a smartphone or PC (for inputting various information) and the information processing device 10 (for calculating the belt tension T) via the Internet (communication line).

[0073] Furthermore, the processes executed in the above-described embodiments may be programs installed on a smartphone, a PC, etc. Furthermore, the programs may be stored in a storage medium.

[0074] The processing executed in the above embodiment may be realized as a method for measuring belt characteristics, such as the resonance frequency F and tension T of the toothed belt 1, using the information processing device 10 or the like.

[0075] Although the embodiments of the present invention have been described above, they are merely illustrative examples and do not particularly limit the present invention, and the specific configurations of each means etc. can be appropriately modified in design. Furthermore, the effects described in the embodiments of the present invention are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments of the present invention. [Example]

[0076] To verify whether the resonant frequency of a transmission belt can be correctly measured using a piezoelectric element, a transmission belt (belt) was wound between a drive pulley DR and a driven pulley DN (with the same diameter as the drive pulley DR), and the resonant frequency was measured and compared using two methods: measurement using a conventional ultrasonic belt tension meter, and measurement using a piezoelectric element.

[0077] In measurements using an ultrasonic belt tension meter, the microphone of the ultrasonic belt tension meter was placed near the center BC between the drive pulley DR and the driven pulley DN, and the belt at that point was struck with a metal rod to vibrate and measure the resonance frequency. Measurements were taken five times, and the average value was used. Note that when measurements were taken using the ultrasonic belt tension meter, no piezoelectric element was attached to the belt.

[0078] In measurements using a piezoelectric element, the piezoelectric element, connected to an FFT analyzer via a lead wire, was attached to a predetermined position with adhesive tape, and then the belt was vibrated by hitting it with a metal rod near the center BC between the drive pulley DR and the driven pulley DN. The change in voltage generated between the two electrodes of the piezoelectric element was converted from a time-axis waveform to a frequency-axis waveform using an FFT analyzer to plot a power spectrum, and the frequency showing the strongest signal in the power spectrum was determined as the resonant frequency.

[0079] [Example 1] In Example 1, as shown in Figure 4, piezoelectric elements were attached with adhesive tape to the outer surface of the belt at positions A to D, from the center BC of the resonating part of the belt to the contact start position with the drive pulley DR (base point RS: the position where the belt starts to wrap around the drive pulley DR). Position A is the position where the belt and the drive pulley DR start to contact each other, and this position is set as the base point RS (0 mm). Positions B to D are located 1 / 6, 1 / 4, and 1 / 2 of the length of the resonating portion of the belt, respectively, away from the base point RS, and the distances from the base point RS are as shown in Table 1. Note that the piezoelectric elements were not attached to all four locations, A to D, at the same time, but were attached to one location for each measurement. Figure 5 shows the power spectrum when the piezoelectric element was attached to position A and measured.

[0080] [Specifications of the belt in Example 1] Belt type: toothed belt Tooth profile: JIS YH tooth profile (8mm pitch) Belt tooth count: 97 Belt width: 12.7mm Pulley teeth count: 24 Resonating part length: 292mm Load: 588N

[0081] [Table 1]

[0082] When the piezoelectric element was attached at positions A and B, the measured value was almost the same as the resonance frequency measured by the ultrasonic belt tension meter, and it was determined that the measurement accuracy was high. In contrast, when the piezoelectric element was attached to positions C and D, a peak was observed at a frequency lower than the resonance frequency measured by the sonic belt tension meter, and it was determined that the measurement accuracy was slightly inferior. This is thought to be because the piezoelectric element was attached to the resonating part of the belt, which inhibited vibration.

[0083] [Example 2] In Example 2, the measurement target was a joined V-belt. The piezoelectric element was attached at the same position as position A in Example 1. The power spectrum measured using the piezoelectric element is shown in FIG.

[0084] [Specifications of the belt in Example 2] Belt Type: Bonded V-belt Belt type: ASABE HB type 6 ribs Belt length: 4260mm Load: 2648N

[0085] The resonant frequency measured with the ultrasonic belt tension meter was 7.19 Hz, while the resonant frequency measured with the piezoelectric element was 7.13 Hz. Because bonded V-belts have a large unit mass and a low resonance frequency, they are prone to measurement errors when used with an ultrasonic belt tension meter, which means that the number of measurement attempts is likely to be large.In this experiment, while measurements using an ultrasonic belt tension meter resulted in multiple measurement errors, measurements using a piezoelectric element were able to measure the resonance frequency in one measurement, and the measured value was almost the same as that measured with the ultrasonic belt tension meter.

[0086] [Example 3] In Example 3, as shown in FIG. 7, piezoelectric elements were attached with adhesive tape to the outer circumferential surface of the belt at positions E to H from the contact start position with the drive pulley DR (base point RS) to the winding portion of the drive pulley DR. Position E is the contact start position (base point RS) between the belt and the drive pulley DR, similar to position A in the first embodiment, and this position is set as the base point RS (0 degrees). Positions F to H are 3 teeth, 4 teeth, and 5 teeth away from the base point, respectively, and the angles (central angles relative to the base point RS and the arcs formed by positions F to H) are as shown in Table 2. Note that the piezoelectric elements were not attached to all four locations (E to H) at the same time, but were attached to one location for each measurement. Figure 8 shows the power spectrum when measurements were taken with the piezoelectric elements attached to locations E to G.

[0087] [Specifications of the belt in Example 3] Belt type: toothed belt Tooth profile: JIS YS tooth profile (8mm pitch) Belt tooth count: 137 Belt width: 15.0mm Pulley teeth count: 30 Load: 570N

[0088] [Table 2]

[0089] When the piezoelectric elements were attached at positions E to G, the measured values ​​were almost the same as the resonance frequencies measured by the sonic belt tension meter, and it was determined that the measurement accuracy was high. In contrast, when the piezoelectric element was attached at position H, the resonant frequency could not be determined, possibly because the voltage generated by the piezoelectric element was too low. Position G is at a central angle of 48 degrees from the contact start position (base point RS) between the belt and drive pulley DR, and position H is at a central angle of 60 degrees from the base point RS. Therefore, it was confirmed that the resonant frequency can be accurately measured even if the piezoelectric element is attached to the belt winding portion, as long as it is within a central angle of 50 degrees from the contact start position (base point RS) between the belt and drive pulley DR.

[0090] [Example 4] In Example 4, the piezoelectric element was attached to the side surface of the drive pulley DR between the winding portion and the rotation center RC of the drive pulley DR. Specifically, as shown in Fig. 9, at least a part of the piezoelectric element was attached with adhesive tape to the side surface of the drive pulley DR at positions I to O within a central angle of 0 to 90 degrees from the base point RS, with the rotation center RC of the drive pulley DR as the central point, and on the outer periphery of the side surface of the drive pulley DR. Position I is a position where the center of the piezoelectric element is located on the outer periphery of the side surface of the drive pulley DR, between the winding portion and the rotation center RC of the drive pulley DR, and the central angle is 0 degrees. Position J is a position where the center of the piezoelectric element is located on the outer periphery of the side surface of the drive pulley DR, between the winding portion and the rotation center RC of the drive pulley DR, and the central angle is 15 degrees. Position K is a position where the center of the piezoelectric element is located on the outer periphery of the side surface of the drive pulley DR, between the winding portion and the rotation center RC of the drive pulley DR, and the central angle is 30 degrees. Position L is a position where the center of the piezoelectric element is located on the outer periphery of the side surface of the drive pulley DR, between the winding portion and the rotation center RC of the drive pulley DR, and the central angle is 45 degrees. Position M is a position where the center of the piezoelectric element is located on the outer periphery of the side surface of the drive pulley DR, between the winding portion and the rotation center RC of the drive pulley DR, and the central angle is 60 degrees. Position N is a position where the center of the piezoelectric element is located on the outer periphery of the side surface of the drive pulley DR, between the winding portion and the rotation center RC of the drive pulley DR, and the central angle is 75 degrees. Position O is a position where the center of the piezoelectric element is located on the outer periphery of the side surface of the drive pulley DR, between the winding portion and the rotation center RC of the drive pulley DR, and the central angle is 90 degrees. Table 3 summarizes the angles (corresponding to central angles) from the base point RS to the arcs drawn by the base point RS and each of the positions I to O. Note that the piezoelectric elements were not attached to all seven locations (I to O) at the same time, but were attached to one location for each measurement. Also, although the illustrated piezoelectric elements are formed in a circular shape, the piezoelectric elements do not have to be formed in a circular shape. The time-axis waveforms and power spectra measured when the piezoelectric elements were attached to positions I, K, M, and O are shown in Figures 10 to 13.

[0091] [Specifications of the belt in Example 4] Belt type: toothed belt Tooth profile: JIS YS tooth profile (8mm pitch) Belt tooth count: 137 Belt width: 15.0mm Pulley teeth count: 34 The load in Example 4 was not adjusted to 570 N as in Example 3, but was adjusted so that the resonance frequency measured with a sonic belt tension meter was 66 Hz.

[0092] [Table 3]

[0093] According to the measurement results in Table 3 and the measurement results of the time axis waveform and power spectrum in Figures 10 to 13, in Example 4, the frequency could be measured almost accurately regardless of the position of the piezoelectric element attached, I to O. However, the maximum output voltage decreased as the attachment position of the piezoelectric element moved away from the base point RS, making measurement difficult. Therefore, when attaching the piezoelectric element to a pulley, it was confirmed that it is preferable to attach it to the side of the pulley at a central angle of 0 to 50 degrees, just as in Example 3, where the piezoelectric element was attached to the belt winding portion. [Explanation of symbols]

[0094] 1 Toothed belt 10. Information processing equipment 11 Control section 12 Storage section 13 Input section 14 Display section 15 Piezoelectric element DR Drive pulley DN driven pulley S span length L: Length of the resonating part R Winding part (drive pulley side) N Winding part (driven pulley side)

Claims

1. a belt wound between pulleys or a piezoelectric element that can be attached to the pulley; a control unit that calculates a resonance frequency of the belt based on a voltage generated by a piezoelectric effect of the piezoelectric element when the belt is vibrated in a stationary state in which the pulley is kept stationary so as not to rotate; a display unit that displays the resonance frequency calculated by the control unit.

2. a belt wound between pulleys or a piezoelectric element that can be attached to the pulley; a storage unit capable of storing the mass per unit length of the belt and the span length, which is the actual distance between the contact points of each pulley and the belt; a control unit that calculates the tension of the belt based on the mass per unit length of the belt and the span length stored in the storage unit, and a resonance frequency of the belt calculated based on a voltage generated by the piezoelectric effect of the piezoelectric element when the belt is vibrated in a stationary state in which the pulley is stationary so as not to rotate; a display unit that displays the tension of the belt calculated by the control unit.

3. 3. The belt characteristic measuring device according to claim 1, wherein at least a part of the piezoelectric element is attached to a winding portion of the belt, which is a portion of the belt that is wound around the pulley.

4. 4. The belt characteristic measuring device according to claim 3, wherein at least a portion of the piezoelectric elements are attached at a position on the winding portion where the belt starts to wind around the pulley, the central angle from the base point being within a range of 0 to 50 degrees with the center of rotation of the pulley as the center point.

5. 3. The belt characteristic measuring device according to claim 1, wherein at least a portion of the piezoelectric element is attached to a side surface of the pulley between a winding portion where the belt in the stationary state is wound around the pulley and a rotation center of the pulley.

6. 6. The belt characteristic measuring device according to claim 5, wherein at least some of the piezoelectric elements are attached at positions within a central angle of 0 to 50 degrees from a position where the belt starts to wrap around the pulley, with the center of rotation of the pulley as a center point.

7. (1a) a step in which the control unit calculates a resonance frequency of the belt based on a voltage generated by a piezoelectric effect of the belt wound between the pulleys or a piezoelectric element attached to the pulleys when the belt wound between the pulleys is vibrated while the pulleys are kept stationary so as not to rotate; (1b) a step in which the control unit displays the resonance frequency calculated in step (1a) on a display unit; To perform the belt characteristics measurement method.

8. (2a) A step in which the control unit calculates a resonance frequency of the belt, which is calculated based on a voltage generated by the piezoelectric effect of the belt wound between the pulleys or a piezoelectric element attached to the pulleys when the belt wound between the pulleys is vibrated while the pulleys are kept stationary so as not to rotate, and calculates the tension of the belt based on the mass per unit length of the belt stored in a memory unit and the span length, which is the actual distance between the contact points of each pulley and the belt; (2b) a step in which the control unit displays the tension of the belt calculated in the step (2a) on a display unit; To perform the belt characteristics measurement method.

9. 9. The belt characteristic measuring method according to claim 7, wherein at least a part of the piezoelectric element is attached to a winding portion of the belt, which is a portion of the belt that is wound around the pulley.

10. 10. The belt characteristic measuring method according to claim 9, wherein at least some of the piezoelectric elements are attached at positions within a central angle of 0 to 50 degrees from a position where the belt starts to wrap around the pulley, with the center of rotation of the pulley as a center point.

11. 9. The belt characteristic measuring method according to claim 7, wherein at least a portion of the piezoelectric element is attached to a side surface of the pulley between a winding portion where the belt is wound around the pulley and a rotation center of the pulley.

12. 12. The belt characteristic measuring method according to claim 11, wherein at least some of the piezoelectric elements are attached at positions within a central angle of 0 to 50 degrees from a position where the belt starts to wrap around the pulley, with the center of rotation of the pulley as a center point.

13. A program that causes a computer to display the resonance frequency of a belt wound between pulleys, On the computer, (3a) A process of calculating a resonance frequency of the belt based on a voltage generated by a piezoelectric effect of the belt wound between the pulleys or a piezoelectric element attached to the pulleys when the belt wound between the pulleys is vibrated in a stationary state with the pulleys kept stationary so as not to rotate; (3b) a process of displaying the resonance frequency calculated in the process of (3a) on a display unit; A program that executes.

14. A program that causes a computer to display the tension of a belt wound between pulleys, On the computer, (4a) A process of calculating the tension of the belt based on the resonant frequency of the belt, which is calculated based on the voltage generated by the piezoelectric effect of the belt wound between the pulleys or the piezoelectric element attached to the pulleys when the belt wound between the pulleys is vibrated in a stationary state with the pulleys stationary so as not to rotate, and the mass per unit length of the belt, which are stored in a memory unit, and the span length, which is the actual distance between the contact points of each pulley and the belt; (4b) a process of displaying the tension of the belt calculated in the process of (4a) on a display unit; A program that executes.

15. 15. The program according to claim 13, wherein at least a part of the piezoelectric element is attached to a winding portion of the belt, which is a portion of the belt that is wound around the pulley.

16. The program according to claim 15, wherein at least some of the piezoelectric elements are attached at a position where the central angle from the base point where the belt begins to wrap around the pulley is within a range of 0 to 50 degrees with the center of rotation of the pulley as the center point.

17. 15. The program according to claim 13, wherein at least a portion of the piezoelectric element is attached to a side surface of the pulley between a winding portion where the belt is wound around the pulley and a rotation center of the pulley.

18. The program according to claim 17, wherein at least some of the piezoelectric elements are attached at a position where the central angle from the base point where the belt begins to wrap around the pulley is within a range of 0 to 50 degrees with the center of rotation of the pulley as the center point.

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