JPH058769Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a means for preventing wear of a motor shaft exposed to water droplets of a motor used in an environment where water droplets are scattered.

(Prior Art) A hot rolling mill in the steel industry is equipped with a hot run table that is about 140 meters long and has about 700 motors between a finishing rolling mill and a winding device. This hot run table conveys the hot steel strip from the finish rolling mill to the winding device without sagging, and at the same time, it uses high-pressure water from both sides of the hot steel strip as appropriate for the purpose of refining the hot steel strip. are being sprayed.

Due to its nature, each transport roll of the hot-transport table requires extremely precise speed control and responsiveness, so the transport roll and its driving DC motor are directly connected over the shortest distance, reducing the mass of the drive system. It's on. For this reason, the DC motor is inevitably exposed to high-pressure cooling water that is sprayed for the above-mentioned tempering of the hot steel strip.

Of course, DC motors have a waterproof structure, but this is done to prevent water from entering the inside of the DC motor and the terminal box, which is the electrical connection part with the outside, and of course the outer skin of the motor. However, it is exposed to the above-mentioned spray water.

However, according to the inventor's experience, the motor shaft of the DC motor used in the hot run table gradually becomes thinner due to exposure to the high-pressure spray water, and in particular, a large amount of the spray water concentrates. However, if the auxiliary waterproof cover 2 is provided, for example, where the motor housing 1 and the motor shaft 3 meet as shown in FIG. 3, or as shown in FIG.
At the point where the motor shaft 3 meets the water droplet (arrow) falling from the motor housing 1 or the auxiliary waterproof cover 2, the entire circumference of the shaft is pierced, as if the motor shaft 3 had been pierced by water droplets (arrows) falling from the motor housing 1 or the auxiliary waterproof cover 2. As shown by the shaded area in the figure, it is subject to wear due to electrical corrosion, etc. This wear and tear progressed until the motor shaft had to be repaired or replaced, posing a major maintenance problem.

(Problems to be solved by the invention) In order to solve these problems, the invention aims to solve the following problems:
As a result of various experiments and studies, we have provided a motor shaft that is inexpensive and has excellent electrical corrosion resistance.

(Means for solving problems) The present invention will be described in detail below based on examples.

In Fig. 1, 1 is the motor housing;
2 is an auxiliary waterproof cover, 3 is a motor shaft, and 4 is a sleeve attached to the motor shaft 3. The state in which the motor shaft 3 and the sleeve 4 are attached includes fitting without a gap or loosely fitting with some gap. Further, 5 and 6 are a coupling ring and a conveyance roller, respectively. Note that the motor is not limited to a DC motor, and may be an AC motor.

The sleeve 4 in this example was made of MC nylon (monomer casting nylon manufactured by Nippon Polypenco Co., Ltd.) and was made to cover the entire motor shaft 3 exposed to water droplets, but it is not limited to this. For example, as shown in Fig. 2 A or B, the MC nylon sleeve can be attached only to the auxiliary waterproof cover 2 where the spray water is concentrated, or to the area near where the motor housing 1 and motor shaft 3 contact. A similar effect can be obtained.

This is because the water flow that conventionally was directed directly onto the motor shaft 3, but if the MC nylon sleeve 4 is attached to the area where the water flow hits, as shown in Figure 2, the water flow will first hit the MC nylon sleeve 4. Since the MC nylon sleeve 4 rotates together with the motor shaft 3, the water flow is blown away by centrifugal force without touching the motor shaft 3, so that it is possible to obtain the effect of preventing wear and tear. To further enhance this effect, it is advantageous to provide a barb 7 at the end of the sleeve, for example as shown.

That is, the sleeve diameter expands by the height of the turn 7, and with this expansion, the centrifugal force increases, causing the water flow to scatter.

In addition, the material of the sleeve is
Although MC nylon was used, any electrical insulator and strength may be used, such as Bakelite or any other type of nylon. If the sleeve is made of such a material, wear and tear on the motor shaft can be completely prevented.

As described above, the installation of the sleeve has been explained, but experiments have shown that methods of coating the motor shaft with tape-like or liquid materials made of the above-mentioned materials take time to coat and cannot be used for long periods of time. This method has the following drawbacks and is less effective than the present invention.

(Effects of the invention) As mentioned above, the motor shaft of the invention is designed to prevent wear and tear of motors used in environments where water droplets are scattered.
In particular, it is extremely effective as a countermeasure against electrical corrosion, and has great benefits in extending the life and maintenance of motors.

[Brief explanation of drawings]

Fig. 1 is an explanatory view showing an embodiment of the present invention, Fig. 2 A and B are explanatory views showing other forms of the sleeve, and Fig. 3 is an explanatory view showing an embodiment of the present invention.
Figures A and B and Figures A and B are explanatory diagrams of conventional examples. 1... Motor housing, 2... Auxiliary waterproof cover, 3... Motor shaft, 4... Sleeve, 5
...Cup ring, 6...Conveyance roller.

Claims (1)

[Claims for Utility Model Registration] 1. A motor shaft characterized in that a sleeve made of an electrical insulator and having a turn at the end is attached to the part of the motor shaft where the motor housing and the motor shaft meet. 2. A motor shaft, characterized in that the sleeve according to claim 1 is attached to the motor shaft portion where the waterproof cover of the motor housing and the motor shaft meet.