JP2000121465A - Apparatus and method for measurement of tension of belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an apparatus and a method in which the tension of a belt is measured simply and precisely by a method wherein the belt is bent to be V-shaped by a pressure body, a pressure force is measured by a pressure-force measuring device and the bending angle of the belt generated when it is pressed is detected by a bending- angle detecting device. SOLUTION: An apparatus 4 for tension measurement is formed by combining a belt-pressure-force measuring device 5, a belt-bending-angle detecting device 6 and a display 7. It is constituted in such a way that it is held easily by hand and that it is brought selectively into contact with a flat belt 3 in a tension measuring operation. The measuring device 5 measures a force when the flat belt 3 is pressed. A pressure part 8, a frame-shaped part and four strain gages, i.e., strain sensing elements, compose the measuring device. A first arm 23, a second arm 24, a first roller 25, a second roller 26, a slit plate, a light emitting element, a light receiving element and a case compose the detecting device 6. The detecting device 6 outputs a bending angle on the basis of the output of the light receiving element. A signal processing circuit converts the output into an angle so as to be output. The pressure-force measuring device and the detecting device 6 are connected to the display 7 via the signal processing circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt tension measuring apparatus and method suitable for measuring the tension of a driving belt used around an engine of an automobile or the like.

[0002]

2. Description of the Related Art Since there is no movable and simple device for measuring the tension of a belt, the tension of the belt is determined by palpation or by a measure of an experienced person. In a magnetic tape device, a tension arm may be provided to control the tension of the magnetic tape, a potentiometer may be coupled to the arm, the tension may be measured by the potentiometer, and the measured output may be used for tension control. However, this type of tension measuring device, i.e., a tension measuring device, is fixedly provided on a magnetic tape device and cannot be used for measuring the tension of another device.

[0003]

When the belt tension is determined by palpation or by the amount of the eye, the result of the determination varies depending on the degree of experience. Also, the determination result varies due to the change in the spring constant of the belt and the number and shape of the pulleys.

Accordingly, an object of the present invention is to provide an apparatus and a method for easily and accurately knowing the belt tension.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems and achieve the above object, the present invention is an apparatus for obtaining data necessary for knowing the tension of a belt. A pressing body for pressing the belt so as to bend in a shape, a pressing force measuring device for measuring a pressing force by the pressing body, and detecting a bending angle of the belt caused when the belt is pressed by the pressing body. The present invention relates to a belt tension measuring device having a deflection angle detecting device. As described in claim 2, it is desirable to integrate the pressing body, the pressing force measuring device and the bending angle detecting device. It is desirable that a display be provided. Further, a means for calculating the belt tension can be provided. It is desirable to determine the belt tension by the method described in claim 5.

[0006]

According to the present invention, the tension of the belt can be easily and accurately determined. That is, data for determining the belt tension can be obtained only by the pressing operation of the belt. Further, according to the invention of claim 2, it is possible to provide a device which is easily carried or carried. Also,
According to the invention of claim 3, the measurement result can be easily known on the display.

[0007]

Embodiments and Examples Next, embodiments and examples of the present invention will be described with reference to FIGS.

[0008]

FIG. 1 shows a first pulley 1 having a radius r1 and a second pulley 2 having a radius r2 and a belt 3 hung thereon.
1 schematically shows a belt transmission consisting of: and a device 4 for measuring the tension of the belt 3 according to a first embodiment of the invention. In this embodiment, the first pulley 1 is a driving pulley, and the second pulley 2 is a driven pulley. The radii r1 and r2 of the first and second pulleys 1 and 2 are set equal to each other.

The tension measuring device 4 is composed of a combination of a belt pressing force measuring device 5, a belt deflection angle detecting device 6, and a display 7, and can be easily held by a human hand. It is configured to selectively contact. That is, the tension measuring device 4 is a portable small measuring device.

The pressing force measuring device 5 measures a force F when the flat belt 3 is pressed, and includes a pressing portion 8 as a belt pressing body, a frame portion 9, and four strain gauges, that is, strain sensing elements. 10a, 10b, 10c, and 10d. The belt pressing portion 8 is formed of a linearly extending plate-like body,
The belt 3 has a tapered tip portion 11 that comes into contact with the belt 3.
Is pressed. The frame-like portion 9 is formed in a quadrangular shape in plan view, and the first and second portions 12 extend in a direction (x-axis direction) orthogonal to a direction (y-axis direction) in which the belt pressing portion 8 extends. , 13 and the first and second
Third and fourth portions 14 and 15 extending in a direction (y-axis direction) orthogonal to the portions 12 and 13 of FIG. The belt pressing portion 8 is connected to the middle of the second portion 13 of the frame portion 9. Therefore, the second portion 13 is divided into one portion 13a and the other portion 13b around the connecting portion of the belt pressing portion 8. A first through hole 16 is formed in one portion 13a so as to generate strain, and a second through hole 1 is formed in the other portion 13b.
7 are formed. Thereby, the circular through holes 16, 1
7 have shrinkage strain generating portions 18 and 19 on one side and stretch strain generating portions 20 and 21 on the other side. The first strain-sensitive element 10a is connected to the first contraction strain generation section 1
8, the second strain-sensitive element 10 b is stuck to the first elongation strain generating section 20, and the third strain-sensitive element 1 b
0c is affixed to the second shrinkage strain generating section 19,
The sensitive element 10d is affixed to the second elongation strain generating section 21. First, second, third and fourth sensitive elements 1
In 0a, 10b, 10c, and 10d, the resistance value increases according to the elongation strain, and the resistance value decreases according to the shrinkage strain.

The four strain-sensitive elements 10a, 10b, 1
As shown in FIG. 4, 0 c and 10 d are connected in a Wheatstone bridge, and this bridge circuit is connected to a pressing force detection circuit 22. The pressing force detection circuit 22 outputs a signal indicating the pressing force F based on the outputs of the four strain sensing elements 10a, 10b, 10c, and 10d. In addition, the resistance value of the strain sensing elements 10a, 10b, 10c, and 10d changes based on the strain, and a method of obtaining the amount of strain or the pressing force F corresponding to the strain based on the change in the resistance value is well known.

The deflection angle detecting device 6 includes first and second arms 23 and 24, first and second rollers 25 and 26,
Shaft 27, slit plate for encoder 28, light emitting element 2
9, a light receiving element 30, and an encoder case 31. Through holes 32 and 33 are provided near the distal end of the pressing portion 8 and near one end of the first arm 23, respectively, and the shaft 27 is rotatably inserted therein. Second arm 2
The vicinity of one end of 4 is fixed to a shaft 27. Further, a slit plate 28 is also fixed to the shaft 27. A cylindrical portion 34 for supporting the first arm 23 is formed on the outer periphery of the slit plate 28. The light emitting element 29 is fixed to the first arm 23, and the light receiving element 30 is a slit 35 of the slit plate 28.
And is fixed to the case 31. The case 31 includes the light emitting element 29 and the light receiving element 30
And is arranged to surround the slit plate 28 and is fixed to the first arm 23.

The first and second rollers 25 and 26 have shafts 36 implanted at the other ends of the first and second arms 23 and 24, respectively.
37 is rotatably supported. The first and second rollers 25, 26 have substantially the same radius. FIG.
, The left end of the first roller 25 is the first arm 2
3 slightly protrudes from the left end, and the right end of the second roller 26 protrudes slightly from the right end of the second arm 24. Therefore, the first and second rollers 25 and 26 can be brought into contact with the belt 3 without being obstructed by the first and second arms 23 and 24.

The first and second rollers 25 in FIG.
The first roller 25 is arranged above the first arm 23, and the second roller 26 is arranged below the second arm 24 in order to align the height positions of 26. In FIG. 3, the distance from axis 27 to the left end of first roller 25 is axis 2
7 is equal to the distance from the right end of the second roller 26. Further, the first and second arms 23 and 24 and the pressing portion 8 and the first arm 23 and the cylindrical spacer portion 34 are respectively formed so as to contact with low frictional resistance. Have been. That is, the shaft 27, the second arm 24, and the slit plate 28 are rotatable with respect to the pressing portion 8,
Further, the first arm 23 is rotatable with respect to the shaft 27.

The slit plate 28 constituting the encoder has a different number of slits in accordance with a change in the angular position. The slit information at each angular position is detected based on the light-emitting element 29 and the light-receiving element 30 to obtain the angle information. Is configured to obtain. Accordingly, the deflection angle detection device 6 shown in FIG. 4 outputs data indicating the deflection angle β based on the output of the light receiving element 30. The signal processing circuit 40 converts the angle β into an angle θ described later and outputs the angle β. The pressing force detection circuit 22 and the deflection angle detection device 6 are connected to the display 7 via a signal processing circuit 40. The display 7 is configured to display the pressing force F and the angle θ. Note that the angle β can be displayed on the display 7. The display 7 of FIG. 4 is supported by the frame 9 as shown in FIG. 2 includes the various circuits of FIG. 4 and is supported by the frame 9.
2 and 3, the strain-sensitive elements 10a to 10a-1
0d and the wiring of the light emitting element 29 and the light receiving element 30 are omitted.

When measuring the pressing force F required for measuring the tension of the belt 3 and the belt deflection angle β, the first and second
In the middle of the pulleys 1 and 2, the pressing portion 8 is arranged so that the direction in which the pressing portion 8 extends and the pressing direction are perpendicular to the longitudinal direction of the belt 3, and the tapered tip 11 of the pressing portion 8 The belt 3 is pressed to bend the belt 3 into a V-shape. When the belt 3 is pressed by the pressing portion 8, the first portion 12 of the frame portion 9 is pressed by hand in the direction indicated by the arrow 42 in FIG. First and second arms 23, 24
Is rotatably supported at the tip of the pressing portion 8,
The other ends of the first and second arms 23 and 24 are the first and second arms.
Is pressed by the belt 3 via the rollers 25 and 26 of the
Arm 23 moves clockwise in FIG.
4 rotates counterclockwise to a position corresponding to the deflection angle β of the belt 3. When it is necessary to quantitatively determine the tension of the belt 3, the pressing force F and the deflection angle β are measured twice, and the first and second measured values F1 and F2 of the pressing force are measured.
And the first and second measurement values β1, β2 of the deflection angle are obtained. Since there is a certain relationship between the tension T of the belt 3 and the pressing force F and the bending angle β, when the pressing force F and the bending angle β are detected, the tension T of the belt 3 is estimated or calculated quantitatively. It is possible to ask.

Next, the relationship among the tension T, the pressing force F, and the deflection angle β of the belt 3 will be described. Here, the distance between the centers of the first and second pulleys 1 and 2 is C. Also belt 3
Is hung on the first and second pulleys 1 and 2 without slack. Further, the belt 3 is pressed by the pressing portion 8 into the first
And the distance between the intermediate position before pressing, that is, the expected pressing position and the winding end or start end position of the belt 3 with respect to the first and second pulleys 1 and 2, respectively. L1. The V-shaped deflection angle generated when the belt 3 is pressed by the pressing portion 8 is represented by β. Also,
The angle of the belt 3 with respect to a virtual straight line 41 that is parallel to a virtual straight line connecting the centers of the first and second pulleys 1 and 2 and that is in contact with the distal end portion 11 of the pressing unit 8 is defined as θ.
Note that there is a relationship of θ = (180 ° −β) / 2 between θ and β. Therefore, when the deflection angle β is detected, θ can be obtained by calculation. The tension of the belt 3 before the belt 3 is pressed by the pressing portion 8, that is, the initial tension is defined as Ti (kg).
The tension after pressing the belt 3 to the angle θ is T
_θ (kg). The force required to extend the belt 3 by 1% is defined as E (kg /%). The value E indicating the elongation includes the deflection of the shaft supporting the pulleys 1 and 2 in addition to the elasticity of the belt 3. Now, the radius r1 of the first and second pulleys 1 and 2,
Assuming that r2 is represented by r1 = r2 = r, the total length L of the belt 3 before being pressed can be expressed by the following equation. L = 4L1 + 2πr (1) Further, the extension ΔL of the belt 3 when pressed by the force F can be expressed by the following equation. ΔL = ｛(1 / cos θ) −1｝ L1 (2) Further, the belt 3 pressed by the pressing force F so as to have the angle θ.
Tension T _theta (kg) can be shown by the following equation. _Tθ = Ti + ｛(△ L / L) 100｝ E (3) The relationship between the tension Tθ of the belt 3 pressed to the angle _θ and the pressing force _Fθ is shown in the vector diagram of FIG. And can be expressed by the following equation. F _θ = 2T _θ sin θ (4) By substituting T _{θ of} (3) into this equation (4), the following equation is obtained. F _θ = 2 [Ti + ｛(△ L / L) 100｝ E] sin θ (5) By substituting equation (2) into ΔL of equation (5), the following equation is obtained. _{F θ = 2 [Ti + {} (1 / cos θ) -1} L1 F θ = 2 [Ti + {(K θ L1 / L) 100} E] sin θ (6) where, in the formula (6) _Kθ indicates {(1 / cos θ) −1}. In equation (6), Ti and E are unknown,
_Fθ , θ, L1, L are known. Two unknowns Ti,
To find E, at least two equations including Ti and E are required. Therefore, the pressing force F and the angle θ are measured a plurality of times (at least two times) by changing the value of the pressing force to obtain, for example, F1, F2, θ1, and θ2. This produces the following two equations. F1 = 2 [Ti + {( K θ 1 L1 / L) 100} E] sin θ1 (7) F2 = 2 [Ti + {(K θ 2 L1 / L) 100} E] sin θ2 (8) above ( The initial tension Ti is obtained based on the equations (7) and (8). Note that, in order to reduce the measurement error, the pressing force F and the angle θ may be increased more than twice, and the average value of the measurement values may be obtained.

The apparatus for measuring the belt tension according to the first embodiment does not include a device for calculating the belt tension Ti in order to reduce the cost. Therefore, a large number of pressing forces F and angles θ
The relationship between the tension Ti and the tension Ti is determined in advance, and a table showing the relationship is prepared. The table shows the tension Ti. Alternatively, a calculation formula for obtaining the tension Ti is stored in a personal computer in advance, and the pressing force F and the angle θ or the angle β are input, whereby the tension T
Find i. Of course, pressing force F, angle θ or β, and tension Ti
When the operator memorizes the value of the tension Ti or the tension T based on the value of the pressing force F and the angle θ or β.
It is possible to immediately know whether or not i is within the normal range.

As apparent from the above, the present embodiment has the following effects. (1) It is possible to accurately know the tension Ti of the belt 3 without depending on intuition. (2) The tension Ti can be known with a simple configuration comprising a combination of the pressing force measuring device 5 and the deflection angle detecting device 6. (3) In a stationary state or a driving state of the belt 3, data for knowing the tension can be obtained by a simple operation of pressing the pressing portion 8 and the rollers 25 and 26 against the belt 3. (4) Since the pressing force measuring device 5, the deflection angle detecting device 6, and the display 7 are integrally configured, a portable or portable and easy-to-handle tension measuring device can be provided. (5) The deflection angle detecting device 6 includes a pair of arms 23 and 24.
And a pair of rollers 25 and 26 and an optical encoder, the angle β can be accurately detected with a simple configuration. (6) The tension Ti can be obtained even if the number of pulleys, the length of the belt, the type of the belt, that is, the elongation, etc., change.
Therefore, a highly versatile tension measuring device can be provided.

[0020]

Second Embodiment Next, a tension measuring device according to a second embodiment will be described with reference to FIG. However, in FIG.
Parts substantially the same as those in FIG. 5 are denoted by the same reference numerals, and description thereof is omitted. The pressing force measuring device 5 and the deflection angle detecting device 6 of the tension measuring device of the second embodiment are configured in the same manner as the first embodiment. The second embodiment is different from the first embodiment in that a tension calculation circuit 51 and a safety determination circuit 52, which are composed of a microcomputer, are provided. Tension calculation circuit 51
Is a digital circuit for obtaining the tension Ti based on the above equations (7) and (8). The safety determination circuit 52 determines whether or not the measurement result of the tension Ti is within a target tension range in which safety can be ensured. The display 7 has a tension Ti
And the safety judgment result are displayed. Note that the safety determination result may be indicated in a display form of the tension determination result. For example, the tension is displayed continuously when it is within the safe range, and the tension is blinked when it is out of the safe range.

The second embodiment has the same effect as the first embodiment, and also has the effect that the tension and the safe range can be easily and quickly known.

[0022]

[Modifications] The present invention is not limited to the above-described embodiment, and for example, the following modifications are possible. (1) The configurations of the pressing force measuring device 5, the deflection angle detecting device 6, and the like can be variously modified. (2) A roller can also be attached to the distal end 11 of the pressing portion 8, and the belt 3 can be pressed via the roller. (3) The angle β can be displayed on the display 7.

[Brief description of the drawings]

FIG. 1 is a front view schematically showing a belt transmission function and an apparatus for measuring belt tension according to a first embodiment of the present invention.

FIG. 2 is an enlarged front view showing the apparatus for measuring belt tension in FIG. 1;

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a circuit diagram showing an electrical connection of the belt tension measuring device of FIG. 2;

FIG. 5 is an enlarged front view of a part of FIG. 1 for explaining pressing force detection and deflection angle detection by the apparatus of FIGS. 1 to 4;

FIG. 6 is a circuit diagram showing an apparatus for measuring belt tension according to a second embodiment.

[Explanation of symbols]

 1, 2 pulley 3 belt 4 tension measuring device 5 pressing force measuring device 6 deflection angle detecting device 7 display

Claims (5)

[Claims] 1. A device for obtaining data necessary to know the tension of a belt, comprising: a pressing member for pressing the belt so as to bend the belt into a V-shape; A belt tension measuring device, comprising: a pressing force measuring device for measuring a pressing force; and a bending angle detecting device for detecting a bending angle of the belt generated when the belt is pressed by the pressing body. . 2. The belt tension measuring device according to claim 1, wherein the pressing force measuring device is connected to the pressing member, and the bending angle detecting device is held by the pressing member. 3. The apparatus for measuring belt tension according to claim 1, further comprising an indicator for displaying an output of the pressing force measuring device and an output of the deflection angle detecting device. 4. The apparatus according to claim 1, further comprising means for calculating the tension of the belt based on an output of the pressing force measuring device and an output of the angle detecting device.
Or the apparatus for measuring belt tension according to 2 or 3. 5. An apparatus for obtaining data necessary to know the tension of a belt, comprising: a pressing body for pressing the belt so as to bend the belt in a V-shape; A step of preparing a belt tension measuring device having a pressing force measuring device for measuring a pressing force and a bending angle detecting device for detecting a bending angle of the belt generated when the belt is pressed by the pressing body; Pressing the belt from a direction perpendicular to the belt by the pressing body, measuring the pressing force with the pressing force measuring device, and detecting the bending angle of the belt with the bending angle detecting device; Determining the magnitude of the tension before pressing the belt based on the pressing force and the deflection angle.