JPH07128165A - Trouble detector for belt - Google Patents

Abstract

PURPOSE:To provide a trouble detector for a belt which is simple, enables the detection of a trouble of the belt with a simple construction as a sensor to display the condition thereof and moreover, the controlling of a motor. CONSTITUTION:In a loop power system having a medium node as looped between a main drive node and a driven node mounted on a prime motor, tension pulleys 6 and 7 are arranged to allow pressing on both outgoing and incoming sides of the medium node supported on a frame in the direction opposed simultaneously or the tension pulleys 6 and 7 are built to be in a cantilever. Strain gauges 11 and 12 are used at this part to make a sensor and a signal from the sensor is connected to a detector 14 with a simple structure to detect a trouble of a belt 3. Thus, the operation of the prime motor is controlled to further allow the displaying of abnormality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt failure diagnosing device using a torque sensor used for detecting the torque of a follower in a winding power transmission system.

[0002]

2. Description of the Related Art In recent years, a winding power transmission system used in a power transmission device has a flexure medium node between a main node that gives motion to the system and a follower node that receives motion from the main node. Although the movement of the belt is transmitted between the two by the tension of the wrapping and the medial joint, the belt may be broken due to its severe use, and it is unavoidable that regular inspection is required. Belt failure detection devices, which constantly monitor and constantly emit a signal in the event of an abnormality, are becoming increasingly popular.

Conventionally, this type of belt failure detection device has been
The configuration shown in FIG. 6 has been common. The configuration will be described below with reference to FIG.

As shown in the figure, a belt 103 as an intermediate node is wound between a driving pulley 101 and a driven pulley 102 to form a power transmission system 104. The driving pulley 101 is driven by a driving machine (not shown), and the torque of the driving pulley 101 is transmitted to the driven pulley 102 by the belt 103. The power transmission system 104 is provided with a torque sensor 105. Torque sensor 105
Includes tension pulleys 106 and 107, and the tension pulleys 106 and 107 are supported by the fixed body 110 via the beams 108 and 109.
Strain gauges 111 and 112 are attached to the plate 9. The tension pulleys 106 and 107 are pressed against the belt 103, and the torque sensor 105 and the photoelectric switch 1
13 is connected to the detection device 114.

In the above structure, the tensions T1 and T2 of the belt acting on both ends of the driven pulley 102 and the driven pulley 1
The relationship of the formula (Equation 1) is established with the torque τ generated in 02.

[0006]

[Equation 1]

From this, it is understood that the strain gauge output is proportional to the torque. Further, since the load torque is obtained by measuring the tension difference between the belts 103 at both ends of the pulley, there is no offset, so that the active range can be widened without depending on the initial tension. Further, the structure also serves as the tension pulleys 106 and 107. Based on the signal from the torque sensor 105 and the signal from the photoelectric switch 113 that determines the origin of rotation of the belt 103, the detection device 1
At 14, the failure of the belt 103 is detected.

[0008]

In such a conventional belt failure detection device, a complicated process for performing signal processing is used in that an averaging method is used to extract only a fluctuation component that appears periodically. A detection device equipped with a microcomputer that requires an algorithm and a photoelectric switch for period measurement are required, and there is a problem that the device is expensive and complicated.

SUMMARY OF THE INVENTION The first object of the present invention is to solve the above problems and to detect a belt failure without using a detection device equipped with a microcomputer for signal processing and a photoelectric switch for period measurement. And

A second object is to simplify the structure of the torque sensor unit. A third purpose is to detect a failure state of the belt, and further to control the operation and notify the failure state.

[0011]

A first means for achieving the first object of the present invention has a medial node wound between a main driving part and a driven part mounted on a prime mover. In the winding power transmission system, a pair of tension pulleys supported by a frame and capable of pressing both reciprocating sides of the medial joint in opposite directions at the same time, a beam supporting the frame on a fixed body, and a distortion of the beam And a strain detecting member for detecting, and a detection device for detecting an abnormal state of the belt based on an output signal from the torque sensor.

Further, in order to achieve the second object, the second means comprises a torque sensor in which the tension pulley is supported by a cantilever and a strain gauge is attached to the cantilever.

A third means for achieving the third object is to add a detection circuit for detecting a failure state of the belt,
The configuration is provided with an operation control device for the prime mover and an alarm device for notifying the failure state.

[0014]

According to the present invention, the generation and scale of cracks can be detected in real time by inputting the output voltage of the torque sensor to the detection device (differential circuit) by the configuration of the first means described above.

Further, with the configuration of the second means, even with a single torque sensor, it is possible to detect a crack in the belt.

Further, the configuration of the third means enables control of operation and notification based on the detected failure.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, since the structure of the conventional example is basically the same, only different parts will be described. The torque sensor 5 detects an abnormal state of the belt 3 and is connected to the detection device 14 composed of the differential circuit shown in FIG.

With the above configuration, the output voltage from the torque sensor 5 shown in FIG. 1 is input to the terminal Vin of the detection device 14 (hereinafter referred to as a differential circuit) shown in FIG. 2, but a circuit having only a differential characteristic. Considering the above, the circuit oscillates with only the capacitor 15 and the resistor 16 and is not practical. That is, when the impedance of Vin is zero, the feedback voltage returned through the resistor 16 has a pole at the frequency determined by the capacitor 15. Therefore, if a resistor 17 and a capacitor 18 are added to the differentiating circuit and the resistor 17 is placed in series with the capacitor 15, the upper part becomes flat as shown in the frequency characteristic diagram of FIG. Since the stability is poor when the resistor 17 is small, the capacitor 18 is inserted in parallel with the resistor 16. Further, although the amplification degree is limited by the effect of the resistor 17, the operation is stable. The resistor 19 makes the output voltage of the operational amplifier 20 stable and ideal, and its value can be obtained by the following equation (Equation 2).

[0020]

[Equation 2]

By using this differentiating circuit, the high frequency component generated by the crack of the belt 3 can be amplified. The output waveform of Vout of the differentiating circuit is shown in FIG.

As described above, according to the belt failure detection apparatus of the first embodiment of the present invention, since the amplitude of the high frequency due to the crack of the belt can be amplified, the occurrence of the crack of the belt can be realized in real time with a simple structure. The scale can be detected.

Next, a second embodiment of the present invention will be described with reference to FIG. As shown in the figure, the tension sensor 21 supports a tension pulley 22 by a cantilever 23, a strain gauge 24 is attached to the cantilever 23, and the tension sensor 21 and the detection device 14 are connected.

With the above structure, the relationship between the tension T3 of the belt 3 and the output voltage of the tension sensor 21 is expressed by the following equation (Equation 3).

[0025]

[Equation 3]

From this, the tension T3 of the belt and the output voltage of the tension sensor 21 have a proportional relationship, and the detection device 14 can detect the voltage change due to the crack of the belt 3.

As described above, according to the belt failure detecting apparatus of the second embodiment of the present invention, the belt tension T
It can be detected by the change of 3.

Next, a third embodiment of the present invention will be described with reference to FIG. As shown in the figure, the detection device 14
A drive device 2 for driving a prime mover 30 by inputting a variable resistor 26 (hereinafter referred to as a differentiating circuit) to a microcomputer 27 by a switching element such as a transistor 25 to drive a prime mover 30.
8 and the notification device 29 are connected to the microcomputer 27.

With the above construction, the voltage change due to the crack of the belt passing through the differentiating circuit enters the switching element such as the transistor 25, the output state thereof is judged by the microcomputer 27, and the operation of the prime mover 30 is controlled by the drive unit 28. The state of cracks in the belt can be displayed on the notification device 29.

According to the belt failure detecting apparatus of the third embodiment of the present invention as described above, it is possible to carry out the operation control and to give an alarm depending on the belt state.

[0031]

As is apparent from the above embodiments, according to the present invention, it is easy to use a microcomputer requiring a complicated algorithm, a photoelectric switch for measuring a period, and the like without using an expensive and complicated device. It is possible to provide a belt failure detection device which is effective in detecting a belt failure with any device.

Further, it is possible to provide a belt failure detection device which is effective in detecting a failure even with one tension pulley.

Further, it is possible to provide a belt failure detection device which is effective in detecting a failure, controlling the electric motor, and reporting the failure.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a belt failure detection device according to a first embodiment of the present invention.

FIG. 2A is a circuit diagram of the same detection device, and FIG. 2B is an output waveform diagram of the same detection device.

FIG. 3 is a frequency characteristic diagram of the detection device.

FIG. 4 is a configuration diagram of the second embodiment.

FIG. 5 is a circuit configuration diagram of a detection device according to the third embodiment.

FIG. 6 is a block diagram of a conventional belt failure detection device.

[Explanation of symbols]

 1 Driving Pulley 2 Driven Pulley 3 Belt 5 Torque Sensor 6,7 Tension Pulley 8,9 Beam 11,12 Strain Gauge 14 Detector 15 Capacitor 16 Resistor 17 Resistor 18 Capacitor 19 Resistor 20 Operational Amplifier 21 Tension Sensor 22 Tension Pulley 23 Beam 24 Strain gauge 25 Transistor 26 Variable resistor 27 Microcomputer 28 Drive device 29 Notification device

Claims (3)

[Claims] 1. A winding power transmission system having a mediation node wound between a main driving part and a driven node attached to a prime mover, and the reciprocating both sides of the mediating part supported by a frame are opposed to each other at the same time. Detection that detects an abnormal state of the belt by an output signal from a torque sensor that includes a pair of tension pulleys that can be pressed in a direction, a beam that supports the frame on a fixed body, and a strain detection member that detects the strain of the beam Belt failure detection device consisting of a circuit. 2. The belt failure detection device according to claim 1, further comprising a tension sensor in which the tension pulley is supported by a cantilever and a strain gauge is attached to the cantilever. 3. The belt failure detection device according to claim 1, further comprising an operation control device for the prime mover and an alarm device for notifying the failure condition in addition to the detection circuit for detecting the failure condition of the belt.