JPH0227236A - Damage detector for weak pin - Google Patents

Abstract

PURPOSE:To achieve a higher automation level of a machine having a weak pin by forming an empty chamber at a weak part of the weak pin. CONSTITUTION:A liquid supply system A comprises an air feeder 9, a labirynth device 7 and pipes 6 and 8 and a liquid pressure detector system B is made up of a pressure sensor 10, an alarm 12 and signal lines 11a and 11b. a downstream end of the supply system A communicates with an empty chamber 2 of a weak pin 1. When a pin 1 is normal, no leak is caused in a pressure air fed from the device 9 and hence, there is no drop in pressure with no flow of air via the device 7. An air pressure within a pipe 6 is kept at a level of air supplied from the device 9. In such a condition, a sensor 10 transmits a pressure data to the device 12, but no alarm is emitted as the air pressure is equal to that of the device 9. In case the weak pin 1 is broken, the pressure air in the empty chamber 2 is released into atmospheric air to lower the air pressure in the pipe 6 because of the existence of the device 7. Thus, likewise, a signal of the sensor 10 is compared with the air pressure of the device 9 to emit an alarm.

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention detects damage to important parts of the machine due to overload and aging fatigue deterioration in the power transmission system of industrial machinery and general machinery, thereby preventing serious accidents. The present invention relates to a device for preventing.

(Prior art) Weak point pins have been widely used in power transmission systems, but when an overload exceeding a predetermined value is applied, the weak point pin breaks at the weak point to protect important parts from damage. .

By the way, in order to automate a mechanical device using such a weak point pin, for example, there is a method in which a signal line is passed through the weak point of the weak point pin, and breakage of the weak point is detected from the cessation of the electrical signal.

((Problem to be solved by l! Ming) However, according to such conventional technology, although it is detected that the weak point pin is in a completely broken state, it is detected that the weak point pin is in a state immediately before breaking. cannot be detected.

In addition, as weak point pins are installed in the power transmission system as mentioned above, fatigue due to repeated stress may cause minute cracks and racks at the weak point. This results in unnecessary breakage, which actually hinders the improvement of machine operating efficiency.

This invention was made based on this background, and can detect that the weak point pin has broken, and can also detect that the weak point pin is about to break at the same time,
This makes it possible to increase the level of automation of machines with weak point pins.

(Means for Solving the Problems) Therefore, the present invention forms a void in the weak point of the weak point pin, fills the void with fluid under pressure, and provides means for detecting the pressure of the fluid. , which constitutes a weak point pin damage detection device.

(Function) Therefore, if the weak point pin breaks, the cavity formed at the weak point will also break and the pressurized fluid will leak, so if the pressure of the pressurized fluid is detected, the weak point pin will break. Breakage can be detected.

In addition, if a microscopic rack is formed at the weak point of the weak point pin due to repeated stress, etc., and the crack grows and opens the void to the atmosphere, pressurized fluid may leak from the void formed at the weak point. Since the pressure decreases, it is possible to detect the state immediately before the weak point pin breaks.

(Example) An embodiment shown in the drawings will be described below.

This example relates to a weak point pin installed between a link pivoted to a gate ring of a water turbine or pump and a guide vane arm pivoted to a guide vane. In such a case, the weak point pin is broken to prevent damage to parts such as the guide vane.

That is, in FIG. 1, 1 is a weak point pin, 2 is a cavity formed in the weak point pin 1, and the cavity 2 is a blind hole formed in the axial direction from one end of the weak point pin 1, This cavity 2 is formed so as to pass through the inside of a weak point 3 formed in a small diameter at the center of the weak point pin 1.

The power obtained by the water turbine is transmitted from the arm 5 of the guide vane to the link 4 via the weak point pin 1 for use, and the weak point pin 1 formed as described above is connected to the arm 5. It is interposed between the link 4 and constitutes a power transmission system.

A damage detection device s as described below is connected to the weak point pin 1.

The damage detection device S consists of a fluid supply system A and a fluid pressure detection system B.

The fluid supply system A consists of an air supply device 9, a labyrinth device 7, and a vibro 8, and the fluid pressure detection system B consists of a pressure sensor 10, an alarm device 12, and signal lines 11a and 11b.

The lower end of the fluid supply system A is communicated with the cavity 2 of the weak point pin 1.

The air supply device 9 uses a compressor or a high-pressure air cylinder, and supplies air at a pressure higher than atmospheric pressure to the cavity 2 of the weak point pin 1 via the labyrinth device 7.

On the other hand, the pressure sensor 10 of the fluid pressure detection system B detects the air pressure in the chamber 2 of the fluid supply system A, but since the weak point pin 1 is small, the labyrinth device 11' A pressure detection port 10a is installed in a vibro which communicates between the vibro 7 and the weak point pin 1, and the air pressure in the vibro is detected as the air pressure in the cavity 2.

This pressure sensor 10 has the pressure detection port 10a.
The pressure measured by the sensor is converted into an electrical signal, and the pressure data is transmitted from the output terminal to the alarm device 12 via the signal line 11a.

Further, llb is a signal line that transmits the air pressure supplied by the air supply device 9 to the alarm device 12.

The alarm device 12 compares the signal from the pressure sensor 10 with the air pressure signal from the air supply device 9, and is controlled by a computer to issue an alarm output etc. if the signal from the pressure sensor 10 is low. .

Note that instead of using the air pressure signal from the air supply device 9, the air pressure signal may be compared with preset reference pressure data and an alarm may be issued.

Next, the operation of this damage detection device fS will be explained.

When the weak point pin 1 is normal, the empty space 2 is a sealed space, so there is no leakage of the pressurized air supplied from the air supply device 9, and therefore there is no flow of air through the labyrinth 1JIf7. , there is no pressure drop.

Therefore, the air pressure inside the vibro is maintained at the air pressure supplied from the air supply device 9.

Note that even in this state, the pressure sensor 10 issues a low pressure to the alarm device 112, but since the pressure is equal to the air pressure of the air supply device 9, no alarm is issued.

If the weak point pin 1 breaks, the pressurized air in the cavity 2 is released to the atmosphere, so air from the air supply device 9 is supplied to the cavity 2 side via the labyrinth device 7. Due to the presence of the labyrinth device 7, the air pressure inside the vibro is reduced.

In such a state, the signal of the pressure sensor is transmitted to the alarm device 1.
Similarly, at 12, the air pressure is compared with the air pressure of the air supply device 9, and an alarm is issued.

By the way, when the weak point pin 1 breaks due to cracks 13 occurring due to repeated stress etc., as shown in FIG. However, after that, the weak point pin 1 breaks due to a small load.

According to the damage detection device S of this embodiment, when the crack 13 is generated and the crack 13 grows to a state where the empty space 2 of the weak point pin 1 communicates with the atmosphere, the same problem occurs as in the case of the breakage of the weak point pin 1 described above. Since a drop in air pressure is detected and an alarm is issued, it is possible to take measures such as replacing the weak point pin 1 just before the weak point pin 1 actually breaks, which has the advantage that the replacement work of the weak point pin 1 is relatively simple. be.

Further, by inputting a signal immediately before the breakage of the weak pin 1 to the water turbine operation control device, it can be used to automatically stop the operation of the water turbine.

In addition, since the pressure level and pressure drop pattern are different between the air pressure drop situation due to the breakage of the weak point pin 1 and the air pressure drop situation due to a crack, such data can be stored in the computer of the alarm device 12. It is also possible to easily issue separate warnings for each situation.

In the embodiment described above, the damage detection device IS is configured for a single weak point pin 1. However, in the case where a large number of weak point pins 1 are installed in a single machine, This can be easily implemented using the circuit configuration shown in the figure.In the following explanation, only the circuit configuration differs from the previously explained embodiment, and the constituent elements of each circuit are the same. Therefore, detailed explanation thereof will be omitted.

That is, in the embodiment shown in FIG. 3, the fluid supply system A is branched into a circuit for each weak point pin 1 on the downstream side of the labyrinth device 7 and the pressure detection port 10a.

Therefore, if any of the weak point pins 1 is broken or a crack has grown, an alarm can be issued. It has the advantage of not requiring the addition of special parts.

In the embodiment shown in FIG. 4, a fluid supply system A is branched for each weak point pin 1 on the upstream side of the labyrinth device 7, and a pressure sensor 10 etc. is added for each weak point pin 1 accordingly. be.

Therefore, it is possible to clearly identify and issue an alarm as to which of the plurality of weak point pins 1 that have been installed has broken or a crack has occurred, and the work of replacing the weak point pin 1 can be carried out efficiently. be able to.

In the embodiments described above, air is used as the fluid, but the present invention is not limited to this, and can be easily implemented using a liquid such as water.

In addition, although the fluid supply system A uses the labyrinth device 1j7, an orifice may be installed in place of the labyrinth device 7, and the air supply system 9 and the weak point pin 1
If you select a small diameter vibro 8 to connect the two, you can create a labyrinth! It is also possible to omit 17.

(Effects of the Invention) As explained above, the present invention forms a cavity at the weak point of the weak point pin, fills the cavity with fluid under pressure, and provides means for detecting the pressure of the fluid. , which constitutes a weak point pin damage detection device.

If the weak point pin breaks, the vacancy formed at the weak point will also break and the pressurized fluid will leak, so if the pressure of the pressurized fluid is detected, the weak point pin will break. can be detected.

In addition, if a microscopic rack is formed at the weak point of the weak point pin due to repeated stress, etc., and the crack grows and opens the void to the atmosphere, pressurized fluid may leak from the void formed at the weak point. Since the pressure decreases, it is possible to detect the state immediately before the weak point pin breaks.

As described above, according to the present invention, in addition to the fact that the weak point pin has broken, it is also possible to detect that the weak point pin is in a state immediately before breaking, which could not be detected with the conventional technology, and based on the detection result, Since it is also possible to take measures such as stopping the mechanical device in advance, the level of automation of the mechanical device using the weak point pin can be increased.

[Brief explanation of the drawing]

The drawings relate to this invention; 1r:IJ is an overall system diagram of one embodiment, and FIG. 2 is the H-! of FIG. 1. ■An explanatory diagram of the growth of a crack in a weak point caused by repeated stress in a cross section. Figure 3 is a system diagram of another embodiment that supports multiple weak point pins. Figure 4 is a system diagram of another embodiment that supports multiple weak point pins. It is a system diagram of an example. S... Damage detection device B... Fluid pressure detection system 2... Weak point 7... Labyrinth device lO... Pressure sensor A... Fluid supply system 1... Weak point pin 3... Vacant room 9...Air supply 5AR 12...Alarm device Diagram Section 1

Claims (1)

[Claims] A damage detection device for a weak point pin, characterized in that a void is formed in the weak point of the weak point pin, this void is filled with fluid under pressure, and means for detecting the pressure of the fluid is provided.