JP2516816B2 - Timing belt vibration measuring device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for measuring vibration of a toothed belt used to drive an automobile engine, for example, in order to obtain the tension of the belt.

[Conventional technology]

Conventionally, as a method of measuring the tension acting on a toothed belt or the like, there is known a method of applying a lateral vibration to the belt and detecting the tension by measuring the frequency thereof. That is,
The frequency and the tension have a fixed relationship, and the tension can be obtained if the weight per unit length of the belt and the span (distance between two pulleys around which the belt is wound) are known.

[Problems to be Solved by the Invention]

The frequency of the belt decreases as the span of the belt increases, but the measuring range of the sensor that normally detects the frequency is limited, and when the span of the belt exceeds a certain length,
The detection accuracy of the frequency is extremely reduced, making it impossible to measure the tension.

In view of the above problems, the present invention provides a timing belt vibration measuring device that enables highly accurate tension detection even for a belt having a long span, and that can be simply and quickly implemented. It was done for the purpose.

[Means for solving the problem]

A vibration measuring device for a timing belt according to the present invention includes lower claws formed on two tip portions of a lower frame member, upper claws formed on two tip portions of an upper frame member, respectively. The side claw and the upper claw sandwich the two different tooth bottoms of the timing belt, which is the belt under measurement, to generate vibration by striking the measured portion of the timing belt, and the frequency of this vibration. And a detection means for detecting.

[Action]

The part to be measured is hit, and vibration is generated in this part to be measured. Since the portion to be measured has a predetermined length, the measurable frequency is always obtained regardless of the length of the belt itself, and the tension of the belt is detected by this.

〔Example〕

 The present invention will be described below with reference to illustrated embodiments.

FIG. 1 schematically shows a usage state of an apparatus according to an embodiment of the present invention. In this figure, a pair of pulleys 11, 12
An endless timing belt 13 is wound around. As will be described later, the measuring device 20 of the present embodiment sandwiches two points of the timing belt 13 to form a measured portion of a predetermined length, hits this measured portion to generate vibration, and the frequency of this vibration is measured. The tension of the timing belt 13 is detected based on the above.

 2 and 3 show the configuration of the measuring device 20.

The lower frame member 21 has a U-shape, and a grip 22 extending outward is provided in the center thereof. The upper frame member 23 has a U-shape corresponding to the shape of the lower frame member 21, and a grip 24 extending above the grip 22 is formed. 2 of the lower frame member 21
The two tips extend parallel to the grip 22 and the claw 21
a is formed. Similarly, the two tips of the upper frame member 23 also extend in parallel to the grip 24, and the claws 22a are formed in the lower portion. The lower frame member 21 and the upper frame member 23 are mutually connected by a pin 25, and a restoring spring (not shown) is provided at this connecting portion.

By gripping the grips 22 and 24 and bringing the grip 24 close to the grip 22, the tip of the upper frame member 23 rotates upward, and the upper frame member 23 and the lower frame member 21 are opened. In this state, the belt 13 as the object to be measured is inserted between the upper frame member 23 and the lower frame member 21 (FIG. 2), and the grip 24 is released.
The upper frame member 23 is restored downward by the breaking force of the restoring spring,
The upper frame member 23 and the lower frame member 21 are closed, and the belt 13 is
It is clamped by a and 22a (Fig. 3).

A vibration sensor 31 is attached inside the lower frame member 21, that is, on the opposite side of the grip 22. The vibration sensor 31 itself is conventionally known and has a U-shaped cross section, and a pair of microphones facing each other is provided inside the vibration sensor 31. The vibration sensor 31 is provided so that the belt 13 is arranged between the microphones in the state shown in FIGS. 2 and 3, and the belt 13 which is the object to be measured is provided.
The sound generated by the vibration of is detected. The measurable frequency range is 35 Hz to 300 Hz. The detection signal of the vibration sensor 31 is transmitted to the calculation display unit 32, where the tension of the timing belt 13 is obtained and displayed as described later.

A hit bar 35 is provided to impart vibration to the belt 13. As shown in FIGS. 4 and 5, the hit bar 35 is swingably attached to the connecting portion 26 of the lower frame member 21 and the grip 22 via a pin 36. Hit bar 35 and tip
37 is located above the belt 13 and is used for tension measurement.
It strikes 13 and the operation piece is on the opposite side of the tip 37.
38 is formed. The curved portion 39 formed in the middle of the hit bar 35 is for preventing the hit bar 35 from interfering with the upper frame member 23. The coil spring 33 is provided by being fitted to the pin 34, one end of the spring 33 is connected to the connecting portion 26, and the other end thereof is connected to the hit bar 35.

Therefore, the hit bar 35 is parallel to the grip 22 in the neutral position, and the tip portion 37 is separated from the belt 13. When the operation piece 38 is flipped downward while the belt 13 is sandwiched by the upper frame member 23 and the lower frame member 21, the tip portion 37 hits the belt 13 by the elastic force of the spring 33 and the belt 13 vibrates. Given. Hit bar 35 is restored to its original horizontal position,
It stands still apart from the belt 13.

Now, there is the following relationship between the frequency and the span of the belt.

Where F is the frequency of the belt span (Hz) G is the acceleration of gravity (981cm / s ² ) R is the weight per unit length of the belt (kgf / cm) L is the span length (cm) T is the belt span tension ( kgf).

As understood from the equation (1), the tension of the belt 13 can be obtained by detecting the frequency.

In order to obtain a more accurate belt tension, an empirical formula may be used in consideration of the characteristics of the measuring device 20 or the span length. As an example of this empirical formula, the inventor has shown that if the span length is 15.24 cm, I got Here, Is.

As described above, in this embodiment, vibration is generated in a specific span of the belt 13 and the tension of the belt 13 is detected from this frequency. As described above, by sandwiching two points of the belt 13 to form a portion to be measured having a predetermined length, a high frequency that can be detected by the sensor 31 can be obtained regardless of the span length of the entire belt 13. . Therefore, the speed of measuring the tension of the belt 13 is improved. Further, the present embodiment is configured so that the operation piece 38 of the hit bar 35 can be flipped while holding the grips 22 and 24 in one hand. Therefore, it is easy to detect the tension, and the tension can be very quickly implemented.

The length of the portion to be measured of the belt 13, that is, the distance between the claws 21a, 21a is preferably 10 cm to 20 cm, and particularly preferably 15.24 cm. This is because a frequency within a predetermined range can be obtained in the required measurement range.

The conversion from the vibration frequency of the belt 13 into the tension does not have to be performed by the calculation display unit 32, and may be performed separately.

The claws 21a and 22a may have any shape as long as the belt 13 can be fixed at two positions.

The shape of the hit bar 35 is not limited, and any material may be used as long as it can generate vibrations on the belt 13.

Further, the vibration sensor 31 is not limited to that of the embodiment, and may be any other sensor.

〔The invention's effect〕

As described above, according to the present invention, even with a belt having a long span, it is possible to obtain the tension with high accuracy, and further, it is possible to obtain the effect that the vibration measurement can be performed easily and quickly.

[Brief description of drawings]

FIG. 1 is a front view showing a usage state of an embodiment device of the present invention, FIG. 2 is a perspective view showing the embodiment device before a belt is sandwiched, and FIG. 3 is an embodiment showing a belt sandwiched. FIG. 4 is a perspective view showing the device, FIG. 4 is a side view showing the hit bar and the grip, and FIG. 5 is a plan view showing the hit bar and the grip. 13 …… Belt 21 …… Lower frame member 23 …… Upper frame member 31 …… Sensor 32 …… Calculation display 35 …… Hit bar

Claims (2)

(57) [Claims] 1. A lower claw formed on each of the two tip portions of the lower frame member, an upper claw formed on each of the two tip portions of the upper frame member, and the lower claw and the upper claw being covered. The timing belt, which is a measurement belt, is provided with a vibration generating means for hitting a measured portion of the timing belt formed by sandwiching two different tooth bottom portions to generate vibration, and a detecting means for detecting the frequency of the vibration. A timing belt vibration measuring device characterized in that 2. The vibration measuring device for a timing belt according to claim 1, wherein the holding means has a U-shape, and a grip extending outward is formed at a central portion thereof.