JPS5925352B2 - brush - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in brushes for electrical machinery.

Copper powder fastening has traditionally been used as a method for connecting lead wires to the plan body.

This method of fixing copper powder involves creating a lead wire insertion hole in the head of the brush body, inserting the lead wire into the lead wire insertion hole, and then filling and crimping copper powder around the lead wire to connect the lead wire. It is. However, with this method, the brush temperature is 10
At present, when the temperature exceeds 0° C., the resistance of the connection portion gradually increases, making it impractical.

The reason for this is that the thermal expansion coefficients of carbon and copper powder, which are the materials of the brush, are different (carbon's thermal expansion coefficient is 4 to 6 x 10-6/℃, copper powder's thermal expansion coefficient is 16.5 x 101/℃). Due to repeated expansion and contraction due to heat cycles over time, a gap is created between the carbon and copper powder, increasing contact resistance.

Furthermore, copper powder has low elasticity and is easily plastically deformed due to the annealing effect of heat, and when the copper powder is crimped, almost no restoring force is produced, and therefore gaps are more likely to form.

Furthermore, if air enters the gap, the copper powder will be oxidized, further increasing the contact resistance.

To solve this problem, we used sponge iron powder to connect the lead wires, and it was confirmed that the lead wire caulking resistance was relatively stable compared to conventional brushes in a 200-hour energization test at 160°C. Ta.

However, if we look at the details, these resistances tend to increase, albeit slightly. This is because when the sponge iron powder is subjected to a long-time energization test, minute voids are created between the lead wire insertion hole and the sponge iron powder, between the lead wire and the sponge iron powder, and in the sponge iron powder, and the air is completely removed from the outside. It is thought that this is because the sponge iron powder itself oxidizes because it is impossible to block it. The object of the present invention is to provide a brush that does not have the above-mentioned drawbacks.

In the present invention, the lead wire is inserted into the lead wire insertion hole provided in the head of the brush body, and the lead wire is connected by filling and crimping sponge iron powder that has been treated with blue-hot brittle around the lead wire. About the brush that comes with it.

That is, in the present invention, as shown in FIG. 1, a lead wire insertion hole is provided in the head of the brush body 1, and after the lead wire 3 is inserted into the lead wire insertion hole, a blue hot wire is placed around the lead wire 3. In order to prevent the oxidation of the sponge iron powder which has been subjected to a blue-hot brittle treatment and to firmly connect the lead wire 3, the sponge iron powder which has been subjected to a blue-hot brittle treatment is filled and then crimped. It is something to do. In the present invention, the blue-hot brittle treatment of sponge iron powder refers to, for example, heating sponge iron powder at 150°C to 400°C for 5 minutes to 1 hour to form an oxide film of Fe3O4 to prevent oxidation. This is a method of treating objects as immobile objects.

Furthermore, sponge iron powder is a powder made of porous particles obtained by reducing Fe hooks. Further, in the present invention, if necessary, a synthetic resin such as phenol resin or epoxy resin may be applied to the upper surface to which the lead wire of the brush is connected.

The upper surface to which the lead wire is connected is the surface of the brush to which the lead wire is connected. The present invention will be explained below with reference to Examples.

Example 1 As a blue-hot brittle treatment, the surface of sponge iron powder (manufactured by Höganäs K.K., trade name MHIOO.28) having the characteristics shown in Table 1 was
A blue oxide film of Fe3O4 was formed at 250° C. for 30 minutes, and then this film was optically filled around the lead wire inserted into the lead wire insertion hole, and then the lead wire was connected by crimping.

Example 2 As a blue-hot brittle treatment, 2
A blue oxide film of Fe3O4 was formed at 50 DEG C. for 30 minutes, and then this film was placed around the lead wire inserted into the lead wire insertion hole, and then the lead wire was connected by crimping.

Example 3 As a blue-hot brittle treatment, 2
A blue oxide film of Fe3O4 was formed at 50°C for 30 minutes, and then this film was filled with light around the lead wire inserted into the lead wire insertion hole, and then the lead wire was crimped to connect the lead wire. Further, as shown in FIG. 2, a phenol resin (manufactured by Hitachi Chemical Co., Ltd., trade name VP-IIN) 4 was applied to the upper surface to which the lead wires of the brush were connected.

Phenol resin 4 was applied to the sponge iron powder which had been subjected to blue brittle treatment for the purpose of further preventing oxidation. Comparative Example 1 A sponge iron powder (manufactured by Höganäs K.K., trade name MHIOO.28) with the characteristics shown in Table 1 was used, and it was not subjected to blue-hot brittle treatment, but was inserted into the lead wire insertion hole or The surroundings of the lead wires were filled with light, and the lead wires were connected in the same manner as in Example 1.

Comparative Example 2 A lead wire using sponge iron powder (manufactured by Höganäs K.K., trade name MH4O.24) with the characteristics shown in Table 2 and inserted into the lead wire insertion hole without undergoing blue brittle treatment. The surrounding area was filled, and lead wires were connected in the same manner as in Example 2.

Comparative Example 3 A lead wire using sponge iron powder (manufactured by Höganäs K.K., trade name MH4O.24) with the characteristics shown in Table 2 and inserted into the lead wire insertion hole without undergoing blue brittle treatment. Light was filled around the periphery, and lead wires were connected in the same manner as in Example 1.

Next, a comparison was made between the brushes of the present invention obtained by the methods of Examples 1, 2, and 3, a conventional brush crimped with only copper powder, and a brush crimped with sponge iron powder that was not subjected to blue brittle treatment. A comparative test of lead wire pull-out strength and caulking resistance was conducted for the brushes of Example 1, Comparative Example 2, and Comparative Example 3.

The results are shown in Table 3. Further, a current was applied to the brush so that the temperature at the center of the brush reached 160° C., and a 400-hour current test was conducted.

The results are shown in FIG. However, the test was conducted using Comparative Example 1 as a comparative example. Although the lead wire pull-out strength of the brush of the present invention is almost the same as that of the brush of the comparative example, it is much improved compared to the conventional brush, and the initial value of the lead wire crimp resistance is lower than that of the present invention. The brush of Comparative Example 1 and the conventional brush had a slightly higher cost than the brush of Comparative Example, but as shown in FIG. In contrast, with the brush of the present invention, almost no change in caulking resistance was observed even when energized for a long time. According to the present invention, between the lead wire insertion hole and the sponge iron powder subjected to the blue-hot brittle treatment, between the lead wire and the sponge iron powder subjected to the blue-hot brittle treatment, and between the lead wire and the sponge iron powder subjected to the blue-hot brittle treatment, the blue-hot brittle treatment is performed. Since no voids are formed in the applied sponge iron powder and the outside air can be completely blocked, a brush with stable performance and almost no change in contact resistance can be obtained even after long-term use.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a brush according to the present invention, and FIG. 2 is a graph showing the relationship between current application time and caulking resistance. Explanation of symbols, 1... Brush body, 2... Sponge iron powder treated with bluish brittle treatment, 3... Lead wire, 4...
・Phenol Jugetsuji.

Claims (1)

[Claims] 1 The lead wire is inserted into the lead wire insertion hole provided in the head of the brush body, and the lead wire is connected by filling sponge iron powder that has been treated with blue-hot brittle treatment around the lead wire and crimping it. brush.