JP2623407B2 - Shaft grounding equipment for ships - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft grounding device between a hull and a propulsion shaft in a ship.

[0002]

2. Description of the Related Art When a propulsion shaft is stopped, a hull outer plate and a propulsion wing are connected with an extremely small resistance through an intermediate bearing or the like. However, while the propulsion shaft is rotating, a lubricating oil film is formed on bearings such as the intermediate bearings, and a large resistance is generated between the propulsion shaft and the hull. It becomes a state of non-corrosion protection.

When a stray current flows into the propulsion shaft in such a state, electrolytic corrosion occurs in the propulsion blade shaft system from which the current flows. In order to prevent such corrosion, a grounding circuit is provided between the propulsion shaft and the hull to escape the stray current flowing into the propulsion shaft to the hull.

[0004] Further, when applying cathodic protection to the propulsion wing,
In the galvanic anode method, the grounding circuit is used to form an anticorrosion circuit generated by an anticorrosion current generated from an anode attached to the stern through seawater (electrolyte) to the propulsion wing and returned to the anode via the propulsion shaft and the hull. Is adopted. Similarly, in the external power supply system, the anticorrosion circuit is formed by connecting the propulsion shaft and the negative electrode of the power supply device.

[0005] Generally, the place where such a shaft grounding device is provided is located in a long term because oil, salty water, dust, or the like easily enters between the propulsion shaft and the slip ring and between the slip ring and the brush. If used over this distance, the electrical contact resistance between the propulsion shaft and the hull increases, resulting in incomplete electrical conduction. As a result, discharge corrosion and electrolytic corrosion occur in the propulsion blade shaft system.

As means for solving such a problem, there has been proposed a method of increasing the adhesion between the propulsion shaft and the slip ring by inserting a flexible thin plate between them and cleaning the brush. (Jun 53-3999)
No. 6).

Further, it is known to seal the boundary between both edges of the slip ring and the propulsion shaft and to use a silver alloy for the material of the slip ring and the brush (Japanese Utility Model Publication No. 63-19326).

However, the above problem between the slip ring and the brush can be solved by selecting the material of the slip ring and the brush, but the increase in the electrical contact resistance between the slip ring and the propulsion shaft has not been solved yet. Is the current situation.

That is, since the joint of the rings cannot be processed and a complete seal cannot be obtained, the surface of the propulsion shaft is corroded by salt-containing water entering from the joint of the slip ring or the joint of the flexible thin plate. However, it has been found that slip rings and the like float due to the intervening corrosion products such as rust and the like, causing a sudden increase in resistance.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to prevent an increase in electrical contact resistance, secure conduction between a hull and a propulsion shaft for a long period, and effectively prevent corrosion of a propulsion wing shaft system. It is intended to provide a grounding device.

[0011]

The above objects of the present invention are achieved by providing a conductive and corrosion-resistant paint layer between a propulsion shaft and a slip ring.

That is, according to the present invention, a conductive and corrosion-resistant paint layer is provided along the outer periphery of a propulsion shaft, and a slip ring made of a thin metal plate is applied to an upper layer thereof. And a brush is brought into contact with the surface of the slip ring.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a simplified sectional view showing an example of a shaft grounding device in a ship according to the present invention. In the figure, 1 is a propulsion axis,
2 is a slip ring, 3 is a conductive and corrosion-resistant paint layer,
4 is a buffer plate, 5 is a stainless steel band (screw type),
Reference numeral 6 denotes a brush, and 7 denotes a brush holder.

In the present invention, a paint layer 3 is provided along the outer periphery of the propulsion shaft 1. The propulsion shaft 1 here includes an intermediate shaft, a thrust shaft, a crankshaft, and the like.

The paint layer 3 provided along the outer periphery of the propulsion shaft needs to have conductivity and corrosion resistance. As the pigment used in this coating material, silver, copper, carbon, nickel, zinc, etc., or a compound or mixture thereof can be used. However, when a silver-based material is used for the slip ring 2 and the brush 6, it is desirable to use the same silver-based pigment. As the vehicle, a vinyl chloride resin, an acrylic resin, an epoxy resin, a urethane resin, an alkyd resin, or the like can be used.

The thickness of the paint layer 3 is desirably 20 μm or more. If the thickness is less than 20 μm, uneven coating can occur, and stable resistance cannot be obtained. Means for providing the coating layer 3 is arbitrary such as spray coating, brush coating and the like.

In the shaft grounding device of the present invention, a slip ring 2 made of a thin metal plate is attached to the upper layer of the paint layer 3. The material of the metal thin plate forming the slip ring 2 is
It is not particularly limited as long as it is a conductive metal, for example, lead,
Examples include copper, silver or alloys thereof.

The thickness of this slip ring is 0.2
It is desirably about 0.5 mm. This thickness is 0.5
mm, the workability is reduced because it is hard and difficult to wind,
If the thickness is less than 0.2 mm, swelling is likely to occur when the film is wound, and the adhesion is poor.

The slip ring 2 is usually fixed at both ends thereof with a stainless steel band 5 of a screw type.
During this time, it is desirable to insert the buffer plate 4 to increase the non-slip and holding area to prevent the tightened portion of the stainless steel band 5 from floating. The buffer plate 4 is preferably made of a polyethylene resin, a polypropylene resin, or various rubbers.

The thus fixed slip ring 2 is in contact with the brush 6, and the two are always in contact. The brush 6 is held by a brush holder 7. The brush 6 is preferably made of a silver alloy or a silver-carbon material.

The shaft grounding device for a ship of the present invention thus obtained can prevent an increase in electrical contact resistance not only between the slip ring and the brush but also between the slip ring and the propulsion shaft. Propulsion shaft conduction is ensured for a long time. As a result, the propulsion wing shaft system can be effectively protected.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments and the like.

Example 1 A conductive and corrosion-resistant paint layer of about 25 μm was applied over a width of 100 mm on the outer periphery of a propulsion shaft having a diameter of 300 mm. The pigment of this conductive paint was silver, and the vehicle was vinyl chloride resin.

A slip ring made of a silver-copper alloy plate (width 80 mm, thickness 0.4 mm) is attached to the outer layer of the paint layer, and both ends of the slip ring are made of polyethylene.
After pressing with 5mm width x 3t), further tightened screw type stainless steel band (width 12.5mm, thickness 0.8m)
m).

Further, using a brush holder short-circuited to the hull side, a silver-copper brush was brought into contact with the slip ring to obtain a shaft grounding device.

Comparative Example 1 A shaft grounding device was manufactured in the same manner as in Example 1 except that the conductive and corrosion-resistant paint layer used in Example 1 was not used.

Comparative Example 2 A shaft grounding device was manufactured in the same manner as in Example 1 except that a lead plate (width 80 mm, thickness 0.4 mm) was used instead of the conductive and corrosion-resistant paint layer used in Example 1. .

Seawater was dropped onto the three types of shaft grounding devices thus obtained, and the rotation was set at 180 rpm. 2. The propulsion shaft was rotated to measure the contact resistance periodically, and the two were compared during a test period of 1000 hours. The results are shown in FIG. The contact resistance was measured by a constant current voltage drop method.

As shown in FIG. 2, the contact resistance of Comparative Examples 1 and 2 started to increase after about 20 hours had elapsed.
After 00 hours, the value showed about 100 times. On the other hand, in Example 1, the increase in the contact resistance was not so remarkable.

After the test was completed, the outer periphery of the propulsion shaft from which the slip ring was removed had black rust in Comparative Examples 1 and 2, whereas the conductive and corrosion-resistant paint layer in Example 1 had a rust. No change was observed on the surface.

[0031]

According to the shaft grounding device of the present invention as described above, an increase in electrical contact resistance is prevented, and conduction between the hull and the propulsion shaft can be ensured for a long time. Therefore, the propulsion wing shaft system can be effectively protected.

[Brief description of the drawings]

FIG. 1 is a simplified sectional view showing an example of a shaft grounding device in a ship according to the present invention.

FIG. 2 is a graph showing the relationship between contact resistance and elapsed time in Examples and Comparative Examples.

[Explanation of symbols]

1: Propulsion shaft, 2: Slip ring, 3: Conductive and corrosion-resistant paint layer, 4: Buffer plate, 5: Stainless steel band (screw type), 6: Brush, 7: Brush holder.

Continuation of the front page (56) References JP-A 62-202498 (JP, U) JP-A 1-93196 (JP, U) JP-A 53-39996 (JP, Y2) JP-A 3-13978 (JP) , Y2)

Claims (1)

(57) [Claims] 1. A conductive and corrosion-resistant paint layer is provided along the outer periphery of a propulsion shaft, a slip ring made of a thin metal plate is applied to an upper layer thereof, and both ends of the slip ring are fixed to the shaft with bands. A shaft grounding device for a ship, wherein a brush is brought into contact with a surface of the slip ring.