JPS62159808A - Bearing abnormality detecting device for propeller shaft system - Google Patents

Abstract

PURPOSE:To enable abnormality monitoring to be carried out for all of bearing portions so as to facilitate maintenance thereof by providing an electric circuit for detecting variation of an electric potential difference generated between a propeller shaft system and a hull and a means for detecting the abnormality on the basis of the results of the detection. CONSTITUTION:An intermediate shaft 6 connected to a main engine and a propeller shaft connected to said intermediate shaft 6 are supported to a hull 1 through an intermediate bearing and a stern tube bearing respectively. A slip type shaft electric potential detecting terminal 9 is fastened to a shaft electric potential detecting terminal fixing pedestal 10 secured to the hull 1 and the measured electric potential is fed to a shaft electric potential monitoring device 8 through a shaft electric potential signal wire 21. When the lubricating state of a bearing is normal and an oil film is retained, a constant electric potential is kept, however, when the cut portions of the oil film are produced due to abnormal condition of the bearing, the electric potential difference between the hull 1 and the intermediate shaft 6 becomes small. Accordingly, with the simple constitution, abnormality monitoring can be carried out to all surfaces of all bearing portions and the maintenance thereof can be facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application on C1] The present invention relates to an abnormality detection device for a shaft system bearing of a ship or a seawater pump.

[Conventional technology]

Generally, in order to detect an abnormality in the shaft system bearing of a seawater pump in a ship, an abnormality detection device is provided in the bearing.

As shown in FIG. 4, in the conventional shaft system bearing section of a ship, a rotating shaft 11 is supported by a bearing section 12 having a metal 12a, and the temperature of the bearing section 12 to be monitored for an abnormal state is A sensor hole 13 is provided, and a temperature sensor 14 having one end connected to a temperature sensor lead #a15 is inserted through the temperature sensor hole 13 to near the surface of the bearing portion 12 on the back surface of the metal 12a.

With the above-described configuration, the temperature of the bearing portion 12 is detected by detecting the rise in the temperature of the metal 12a using the temperature sensor 14.

[Problem that the invention seeks to solve]

However, such a conventional propeller shaft system bearing abnormality detection device has the following problems.

(1) It is necessary to machine the temperature sensor insertion hole 13 inside the bearing metal 12, and it is possible to detect abnormalities in the bearing metal 12 near where the temperature sensor ↓ is embedded, but in the part far from the temperature sensor 14. No abnormality can be detected.

(2) When a temperature rise in the bearing metal 12 is detected, the bearing has already experienced an abnormality, and the occurrence of an abnormality cannot be known in advance.

The present invention aims to solve the above-mentioned problems, and therefore provides a bearing abnormality detection device for a propeller shaft system that can detect the occurrence of bearing abnormalities in advance and facilitate maintenance and inspection work. With the goal.

[Means for solving problems]

For this reason, the propeller shaft system bearing abnormality detection device of the present invention has the following features:
An electric circuit is provided to detect changes in the potential difference generated between the propeller shaft system including the propeller shaft, intermediate shaft, and main crank and the Qj body, and based on the detection results by the electric circuit, the It is characterized by the provision of a hand f2 for detecting an abnormality.

In other words, the oil Il generated between the bearing and the rotating shaft is detected as a bearing abnormality! ! Focusing on I7, the tendency of the oil film to decrease can be instantaneously detected electrically, and the potential difference that naturally occurs between the bearing and the rotating shaft is utilized.

[Effect]

In the propeller shaft system bearing abnormality detection device of the present invention described above,
Electrical potential Z1 generated by the electric circuit between the propeller shaft system and the hull
Based on this detection result, an abnormality in the bearing portion of the propeller shaft system is detected.

〔Example〕

Hereinafter, a bearing abnormality detection device for a propeller shaft system as an embodiment of the present invention will be explained with reference to the drawings. Fig. 1 is an overall configuration diagram thereof, Fig. 2 is a diagram illustrating a method of installing a subpotential monitoring device, and Fig. FIG. 3 is a block diagram of the same device.

As shown in FIG. 1, the l1lI system (propulsion system) of the main engine for ships consists of an intermediate shaft 6 connected to the main engine 7, a propeller shaft 5 connected to the intermediate shaft 6, and recessed by the propeller 2. The intermediate shaft 6 is supported by the hull via an intermediate bearing 4, and the propeller shaft 5 is supported by the hull via stern tube bearings 3, 3.

Furthermore, between the QO body 1 and the intermediate shaft 6, there is provided a 7.
A @+ potential monitoring device 3 as an RI circuit is provided.

As shown in FIG. 2, this potential monitoring device 8 is disposed on the intermediate shaft 6 and connected to a power source (not shown) via a power source wire 24. A slip-type Tsumugi potential detection end 9 is attached to a Tsumugi potential detection end fixing base 10 fixed to the hull 1. The tip of the detection end 9 is pressed against the circumferential surface of the intermediate shaft 6 by a force such as a spring, and measures the potential of the intermediate shaft 6 while slipping. The measured potential is sent to the sleeve potential monitoring device 8 connected by the Tsumugi potential signal fill.

Note that the portion 1 that comes into contact with the shaft potential output end of the intermediate shaft 6 is wrapped with a material having good Q conductivity, such as a silver band.

Further, the shaft potential monitoring device 8 is connected to the hull 1 via a ground wire 22, and measures the potential of the hull 1. Further, the shaft potential monitoring device 8 is also connected to an alarm signal wire 25 to output an alarm signal.

As shown in FIG. 3, the sleeve potential monitoring device 8 includes a Tsumugi potential signal converter 26, a noise filter 27, an alarm level setting device 28, a comparator 29,'! ! The system compares the potential between the hull 1 and the intermediate 1llll6, detects an abnormality in the bearing based on the change in potential, and issues an alarm signal if necessary. ing.

The bearing abnormality detection device for a propeller shaft system according to an embodiment of the present invention has a groove structure as described above.
When is rotating, propeller shafts 5 and 1 are in between? lI
] 6 and the hull are electrically insulated at the stern tube bearing 3 and the intermediate bearing 4 by an oil film in the bearing portion.

Here, when the propeller 2 made of aluminum and the hull 1 made of copper plate are in electrolyte seawater,
A certain potential difference occurs between these different metals due to their ionization tendency.

Therefore, the bearings 3 and 4 in the propeller shaft system and the soil are
If the lubricating state of the internal pad holder and thrust bearing (not shown) is normal and the oil film is properly maintained, a constant sleeve potential is maintained.

Such a potential difference between the intermediate shaft 6 and the hull 1 is measured and monitored by a sleeve potential KZ viewing device 8.

In other words, in the Tsumugi potential monitoring device 8, as shown in FIG.
The detected potentials of the hull 1 and the intermediate shaft 6 are input to the sleeve potential signal converter 26 via the shaft potential signal line 21 and the ground wire 22, respectively, and are converted into signals at the required level by the sleeve potential signal converter 26. At the same time, noise in the signal is filtered and removed by the /ear filter 27, and taken out as an actual measured axis potential signal.

On the other hand, a required alarm level is set by the alarm level setting device 28, and a setting signal B is generated.

Then, the comparator 29 compares the levels of the input actual measurement axis potential signal A and the alarm level setting signal B,
If A is greater than B, m without emitting an alarm signal.
A surveillance car is then carried out.

If any abnormality occurs in the bearings (not shown) of the propeller shaft 5 or intermediate shaft 6 that are electrically connected to the propeller 2, or in the bearings (not shown) of the main (71)
: If even a slight break in the oil film occurs between the system and the bearing metal, a minute current flows through the break in the oil film due to the potential difference mentioned above and is discharged, causing a change in potential difference. In other words, the potential difference between the hull 1 and the intermediate shaft 6 becomes smaller.

When the Tif difference becomes smaller, the level to the actual measured axis potential signal also becomes smaller.And the comparator.
- Compare the alarm level setting No. 53B with the alarm level setting No. 53B at
The alarm signal wire 25 is then sent to an alarm device (not shown).

Therefore, by constantly monitoring the potential difference between the intermediate shaft 6 (rotating shaft system) and the hull 1 (Illll receiving part) with the shaft potential monitoring device rrL8 at a certain time when an oil film is formed, changes in the potential can be detected instantaneously. It is possible to detect abnormalities in the shaft system bearings.

In addition, we can predict abnormalities in the shaft system bearings based on the tendency of changes.
It can also be detected much earlier.

If a shaft grounding device is installed, a constant weak grounding current always flows through the p# grounding section, but if the current in this section changes or the shaft system and grounding section at this section Abnormalities in the bearing portion can also be detected by monitoring changes in the potential difference in the same manner as described above.

〔Effect of the invention〕

As described in detail above, the propeller shaft system bearing abnormality detection device of the present invention detects a change in the potential difference that occurs between the propeller shaft system including the propeller shaft, intermediate shaft, and main crank, and the hull. This is an extremely simple purchase that includes a means to detect abnormalities in the bearings of the propeller shaft system based on the detection results from the Ti air circuit. This makes it possible not only to monitor abnormalities, but also to detect very early abnormalities based on changing trends.

Also, since a monitoring device is installed outside the bearing, one hole for the temperature sensor is machined in the bearing. : Not only does this eliminate the need for additional maintenance, but it also facilitates maintenance and inspection of the device.

[Brief explanation of drawings]

Figures 1 to 3 show a bearing abnormality detection device for a propeller shaft system as an embodiment of the present invention. Figure 1 is an overall diagram of the groove, and Figure 2 explains the mounting means of the glaze potential monitoring device. figure to do,
FIG. 3 is a block diagram of the same device, and FIG. 4 is an overall schematic diagram of a conventional bearing abnormality detection device for a propeller shaft system. 1. Hull, 2. Propeller, 3. Stern tube bearing, 4.
・Intermediate bearing, 5...Propeller shaft, 6...Intermediate shaft, 7...
Dosei Seki, 8... Sleeve potential monitoring device, 9... Shaft potential detection end,
10... Sleeve electric cry detection end fixing stand, 21... Shaft potential signal line,
22... Earth wire, 24... Power supply wire, 25... Alarm signal wire, 26... Shaft potential signal converter, 27... Noise filter, 28... Alarm level setting device, 29...
Comparator, 30...Alarm signal transmitter. Sub-Agent Patent Attorney Yoshihiko Iinuma Figure 1■ Figure 4

Claims (1)

[Claims] Equipped with an electric circuit to detect changes in potential difference occurring between the propeller shaft system, including the propeller shaft, intermediate shaft, and main engine crank, and the hull, and based on the detection results by the electric circuit, abnormalities in the bearing part of the propeller shaft system are detected. What is claimed is: 1. A bearing abnormality detection device for a propeller shaft system, characterized in that it is provided with means for detecting.