JPH02190727A - Measuring instrument for tension of belt - Google Patents

Abstract

PURPOSE:To measure tension of belt accurately and easily by providing an input means, resonance frequency detecting means, arithmetic means and display means. CONSTITUTION:A sound collecting microphone 56 is connected to an acoustic pressure-voltage signal converter 60 as an input means. The acoustic pressure caused by the vibration of the belt, which is collected by the microphone 56, is converted to an electrical signal. The converter 60 is connected to a frequency analyzer 58 through an A/D converter 62. Frequency series signals obtained by the analyzer 58 are inputted to a peak-hold circuit 64 which is the resonance frequency detecting means, wherein the resonance frequency can be obtained by the change of amplitude during from the beginning up to the ending of the belt vibration. A map indicating the relation between the resonance frequency calculated by a specified equation and the tension is stored in a storage circuit 66. By a frequency-tension converter 68 consisting of the arithmetic circuit together with the storage circuit 66, the tension is specified from the resonance frequency obtained by the circuit 64 and data in the storage circuit 66 then displayed 70.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a belt tension measuring device that measures tension by vibration of a belt.

[Conventional technology]

A driving force transmission belt is known that is wound between a pair of pulleys and transmits the rotational force of the pulleys.

For example, in an image recording device that rotates a recording material wrapped around the outer periphery of a recording drum and records an image using a recording head, sub-scanning is performed by moving the recording head relatively in the direction of the recording drum axis. It is used as a means of transmitting driving force when

In this case, a pulley is attached to the motor for driving the recording head, and a belt is wound around this pulley to connect it to another pulley having a different diameter. In addition, another belt connected to the recording head is wrapped around the other pulley, so that the driving force of the motor is transmitted to the recording head and the recording head is moved in the axial direction of the recording drum. .

Further, a low-return encoder is attached to the motor, and this encoder detects and feeds back the rotational speed of the motor to control the rotational speed of the motor to a predetermined speed.

According to this driving force transmission belt, by using a steel belt with high rigidity and no sag,
The driving force of the motor (pulley) can be reliably transmitted to the recording head. Therefore, the rotation of the motor whose rotational speed is precisely controlled by the encoder can be accurately transmitted to the recording head, and, for example, the sub-scanning line pitch will not become unstable.

[Problem to be solved by the invention]

By the way, in such a driving force transmission belt, in order to reliably transmit the driving force of the boob, the tension of the belt is wound at a predetermined optimum value, and then this tension is kept at a predetermined optimum value. needs to be adjusted so that it is maintained.

In this regard, in the past, the tension of the belt wound around the boob was measured using a device such as a tension meter so that the tension reached a predetermined optimum value. However, with such a device, it is not possible to measure this tension in an image recording device or the like where the space around the pulley or belt is narrow. Furthermore, such a mechanical method of measuring belt tension has a large measurement error, which makes it impossible to obtain an accurate tension.

The present invention has been made in consideration of the above facts, and an object of the present invention is to provide a belt tension measuring device that can accurately and easily measure belt tension regardless of the width of the space around the belt.

[Means to solve the problem]

The belt tension measuring instrument according to the present invention includes an input means for detecting the sound pressure when the belt is vibrated and converting the sound pressure into an electrical signal, and a resonant frequency that is determined by frequency-analyzing the temporal change of the electrical signal. a resonant frequency detecting means for detecting the resonant frequency, a calculating means for calculating the tension corresponding to the resonant frequency detected by the resonant frequency detecting means, and a display means for displaying the tension calculated by the calculating means. .

[Effect]

According to the invention, the belt whose tension is to be measured is vibrated,
The sound pressure generated by this vibration is detected by the input means and converted into an electrical signal. The converted electrical signal changes depending on the amplitude of the vibration, and the resonance frequency detection means frequency-analyzes the temporal change in the electrical signal, converts it into a frequency sequence signal, and detects the resonance frequency. The calculation means calculates the tension based on this resonance frequency. The calculated tension is displayed by the display means, and the belt tension can be obtained by simply vibrating the belt.

As described above, according to the present invention, the tension can be obtained simply by measuring the sound pressure obtained by vibration of the belt, so the tension can be measured accurately and easily regardless of the size of the space around the belt. Can be done.

〔Example〕

FIG. 1 shows a driving force transmission device 1O to which a belt measured by a belt tension measuring device 11 according to the present embodiment is applied.

The driving force transmission device 10 includes a plurality of pulleys 12 having different diameters.
．． 14.16.18.20 are located. Pulley 1
2 is a rotating shaft 26 of the motor 24 fixed to the upper substrate 22
It is fixed to the motor 24 and rotates together with the motor 24.

On the other hand, the pulleys 14 and 16 are each fixed to a rotating shaft 30 that is rotatably supported on the middle board 28, and the pulleys 18 and 20 are each fixed to a rotating shaft 34 that is rotatably supported on the lower board 32. It is fixed.

A steel belt 36 is wound around the pulleys 12 and 14, and a steel belt 38 is further wound around the pulleys 16 and 18. Also pulley 20
A steel belt 40 connected to another device (for example, an exposure head, etc.), not shown, is wound around the motor 24, and thereby the rotational force of the motor 24 is transmitted by changing the speed (deceleration) by a predetermined amount. There is.

Each pulley has its circumferential surface (steel belt 36.3
8.40) is etched to increase the friction coefficient of the circumferential surface, and the steel belt 36.
38.40 prevents slippage.

The motor 24 is connected to a control device (not shown) and is activated based on an activation signal.

A plurality of elongated holes 4 are provided in the upper substrate 22 to which the motor 24 is fixed.
Further, a fixing bolt 44 is passed through the elongated hole 42 and then screwed into the intermediate board 28. One end of the upper substrate 22 (on the near side in the drawing) has a bent portion 46 bent downward in an L-shape, and further includes an adjustment bolt 4.
8.50 are screwed together. The tip of the adjustment bolt 48 is designed to engage only the tip of the middle board 28. Therefore, by screwing in (or unscrewing) this adjustment bolt 48, the connection between the top board 22 and the middle board 28 is adjusted. relative position,
That is, the distance between the rotating shafts 26 and 30 (in other words, the tension of the steel belt 36) can be changed.

Note that when changing this relative position, loosening the fixing bolt 44 allows the fixing bolt 44 to move within the elongated hole 42, and prevents interference during relative movement between the upper substrate 22 and the middle substrate 28. It has become.

On the other hand, a plurality of elongated holes 52 are formed in the lower substrate 32 on which the rotating shaft 34 is rotatably supported, and the elongated holes 5
A fixing bolt 54 is inserted into the inner substrate 2 and then screwed into the inner board 28. Further, the tip of the lower substrate 32 is connected to the upper substrate 22.
It is designed to engage only with the adjustment bolt 50 that is screwed into the bent portion 46 of the board. Therefore, by screwing in (or unscrewing) this adjustment bolt 50, the relative position between the lower board 32 and the middle board 28 can be adjusted. , that is, the rotating shaft 34 and the rotating shaft 30
(In other words, the tension of the steel belt 38)
can be changed.

In this case as well, by loosening the fixing bolts 54, the fixing bolts 54 can move within the elongated holes 52, so that they do not interfere with each other when the lower substrate 32 and the middle substrate 28 move relative to each other. There is.

The steel belt 36.38 wrapped around each pulley is
The vibration state is measured by a sound collecting microphone 56 that constitutes a part of the input means. Sound collection microphone 5
6 is connected to a belt tension measuring device 11, and the configuration of the belt tension measuring device 11 will be described below.

As shown in FIG. 2, the sound collecting microphone 56 is connected to a sound pressure-to-electrical signal converter 60 (hereinafter referred to as an S/E converter 60) which serves as an input means together with the sound collecting microphone 56. The sound pressure due to belt vibration collected by the belt 56 is converted into an electrical signal. S/E
The converter 60 is an analog/digital (A/D) converter 6
2, a frequency analyzer (F
FT) 58. Note that a spectrum analyzer is used for frequency analysis of such electrical signals.

The FFT 58 has the role of frequency-analyzing the temporal change of the input electrical signal and converting it into a sine wave frequency sequence signal. The frequency sequence signal obtained by the FFT 58 is passed through a peak hold circuit 64 which is a resonance frequency detection means.
The resonance frequency f, which is the maximum value, is obtained from the frequency sequence signal. Thereby, the resonant frequency f can be obtained from the change in amplitude from the start to the end of the belt vibration.

Here, the resonant frequency f (1/s) of the belt is f=1/
2L-677 mouth...(1) L: Belt length (cm) S: Belt tension (kg) g: Gravitational acceleration (cm/52) T: Belt linear density (kg/cm) There is a certain relationship. be. Both L and T are constants unique to the belt, and therefore, the belt tension S is determined from the resonant frequency f of this belt. The belt tension measuring device 11 of this embodiment has a built-in memory circuit 66 that constitutes a part of the calculating means, and the memory circuit 66 stores the resonance frequency f and the tension S calculated by the above equation (1). A map showing the relationship or a map obtained by adding correction values to this map is stored in advance. The storage circuit 66 and the peak hold circuit 64 are connected to a frequency-tension (f/S) converter 68 which constitutes a calculation means together with the recording circuit, and the tension is calculated from the resonant frequency f obtained by the peak hold circuit 64. It is now possible to specify S. Further, the f/s converter 68 is connected to a display 81B70 so that the specified tension S can be displayed.

Next, the operation of this embodiment will be explained.

First, a procedure for measuring the tension of the steel belt 36 will be explained. Note that the tension of the steel belt 38 can be measured using the same procedure, so the explanation thereof will be omitted.

First, the steel belt 36 is vibrated, and the sound pressure caused by this vibration is detected by the sound collecting microphone 56 and input to the belt tension measuring device 11. The sound pressure from the sound collecting microphone 56 is S
The signal is converted into an electrical signal by the /E converter 60, then digitized by the A/D converter 62, and then input to the FFT 58. The FFT 58 performs frequency analysis on temporal changes in the input electrical signal. That is, an electric signal that changes over time is decomposed into sine waves with different frequencies by Fourier transform, and the amplitude and phase of each component sine wave is analyzed. When the frequency is analyzed, the peak hold circuit detects the frequency with the maximum amplitude and holds this as the resonance frequency f. The resonant frequency held by the peak hold circuit is
The tension is supplied to the f/S converter 68 and the tension based on this resonance frequency f is specified. That is, the f/S converter 68 has
A memory circuit 66 in which a map indicating the relationship between resonance frequency and tension is stored is connected, and the tension S is specified based on the input resonance frequency f. The specified tension S is supplied to the display section 70 and displayed, so that the tension of the steel belt 36 can be visually confirmed.

In this way, in this embodiment, the tension can be checked simply by vibrating the steel belt 36, and if an appropriate tension is determined in advance, the tension can be easily adjusted by the tension adjustment procedure shown below. can do.

That is, the steel belt 36 displayed on the display section 70
The measured value of the tension is compared with a preset tension, and the positions of the rotation axes of the pulleys 12 and 14 are adjusted so that the measured value matches the set value.

First, with the fixing bolt 44 loosened,
4 can move within the elongated hole 42, and the adjustment bolt 48
By screwing in (or unscrewing), the relative position between the upper substrate 22 and the middle substrate 28, that is, the distance between the rotation shafts 26 and 30, is changed.

By firmly fixing the fixing bolts 44 after the adjustment is completed, the relative position between the upper substrate 22 and the middle substrate 28, that is, the distance between the rotating shafts 26 and 30, will not change thereafter.

After the tension adjustment of the steel belt 36 is completed, the steel belt 38 wound around the pulleys 16 and 18 is vibrated, and the tension is similarly measured by the sound collecting microphone 56 and displayed on the display section 70, and the tension is set in advance. Adjust the rotation axis positions of pulley 16 and pulley 18 to match the tension.

That is, by loosening the fixing bolt 54 so that it can move within the elongated hole 52, and screwing in (or unscrewing) the adjusting bolt 50, the lower board 3
2 and the intermediate substrate 28, that is, the distance between the rotating shafts 34 and 30 is changed. As a result, the tension of the wrapped steel belt 38 becomes the optimum tension.

After the adjustment is completed, by firmly fixing the fixing bolts 54, the relative position between the lower substrate 32 and the middle substrate 28, that is, the distance between the rotating shafts 34 and 30, will not change.

In this way, according to this embodiment, the tension can be measured simply by vibrating the steel bell (36, 38) wrapped around each pulley, so it can be measured accurately regardless of the space around these pulleys or the steel belt. Moreover, adjustment can be easily carried out, not only during the initial assembly of the steel belt 36.38, but also afterward in order to maintain the tension of the steel belt 36.38 in the drive power transmission device IO at a predetermined optimum value. Adjustments can be made accurately and easily even when making adjustments.

In addition, a device for tension measurement is installed on each driving force transmission device 1.
It is no longer necessary to provide it at 0, and it is possible to downsize the device and reduce costs.

Further, in this embodiment, an endless belt wrapped between a pair of bobbins has been described, but the present invention is not limited to this.
It is also applicable to simply measuring the tension of a belt stretched between two points. Furthermore, it is also possible to apply the present invention to a device provided with a tension roller or the like for setting the tension of the belt, and in this case, the tension can be adjusted more accurately.

In this embodiment, the relationship between the resonance frequency and the tension is stored in the recording circuit 66 in advance, but the relationship may be calculated using the equation (1) above.

〔Effect of the invention〕

As explained above, the belt tension measuring device according to the present invention has the excellent effect of being able to accurately and easily measure the belt tension regardless of the width of the space around the belt.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a belt tension measuring device and a driving force transmission device according to this embodiment, and FIG. 2 is an internal configuration diagram of the belt tension measuring device. 11... Belt tension measuring device, 56... Sound collection microphone, 58... FFT. Figure 1: S/E converter, ・Peak hold circuit, ・Memory circuit, ・Display section.

Claims (1)

[Claims] (1) An input means that detects the sound pressure when the belt is vibrated and converts this sound pressure into an electrical signal, and a resonance frequency detection means that detects the resonance frequency by analyzing the frequency of the temporal change in the electrical signal. A belt tension measuring instrument comprising: a calculating means for calculating a tension corresponding to the resonance frequency detected by the resonant frequency detecting means; and a display means for displaying the tension calculated by the calculating means.