JPS6037695B2 - commutator - Google Patents

Description

[Detailed description of the invention] This invention relates to a commutator.

The secondary commutator uses a capacitor to absorb the arc generated during commutation, but since this capacitor is fixed to the rotor, the dynamic balance of the rotor is poor, and the number of parts increases, which increases cost. It was high.

Therefore, an object of the present invention is to provide a commutator that has good dynamic balance, has a small number of parts, and can suppress arcing.

This invention uses a negative pressure resistor whose resistance value decreases when pressure is applied and whose resistance value increases when pressure is removed.

As a negative pressure resistor having such characteristics, there is Conductive Elastomer (trade name) manufactured by Comerix Corporation (USA).
An embodiment of the invention is shown in FIGS. 1 and 2. In these figures, C and -C3 are commutator segments, S is a slit, R and -R3 are negative pressure resistors, 1 is an insulating substrate, L-L are rotor coils, and B and B2 are brushes. Next, the operation will be explained with reference to FIGS. 3 to 6.

First, in the state shown in FIG. 3a, the brush B is on the segment C, and the negative pressure resistor R is still at a high resistance and does not form a conductive region. Therefore, the electrical circuit is shown in Figure 3b.
It looks like this. Next, when the state shown in Fig. 4a is reached, the contact pressure of the brush B is applied to the negative pressure resistor R,
Its resistance value decreases and a conductive region is formed, shorting segments C, , C2. At this time, segments C,,C
2 is brush B. As a result, the coil L becomes short-circuited as shown in FIG. 4b. Next, the fifth
When the state shown in figure a is reached, segments C, , by brush B,
Although the short circuit of C2 is released, since the negative pressure resistor R, is in the conductive region due to the contact pressure of the brush B, FIG.
As shown in FIG. 2, the coil L is in a short-circuited state, so that no surge voltage is generated in the coil L, and arc generation can be avoided. Next, when the state shown in FIG. 6a is reached, the resistance value of the negative pressure resistor R becomes high and becomes insulated, and the short circuit of the coil L is released as shown in FIG. 6b. In the embodiment, the negative pressure resistors R, to R3 are provided at the bottom of the slit S, but the same effect can be obtained even if they are provided to fill the slit S.

As described above, in the commutator of the present invention, a negative pressure resistor having a high resistance value when no pressure is applied and a low resistance value when pressurized is arranged in the slit so as to be in contact with adjacent commutator segments. , the sashiko is arranged so as to move over the negative pressure resistor of the bracket, and the resistance value is reduced by the contact pressure of the brush against the negative pressure resistor when the brush crosses the slit. Therefore, when the brush crosses the slit, the resistance value of the negative pressure resistor decreases, shorting the coil and preventing arcing, preventing radio wave interference and extending the service life. Moreover, since the resistance value of the negative pressure resistor is high when the rigid element is located away from the slit and in the middle of the commutator segment, the coil short circuit is canceled and resistance loss can be extremely reduced.

[Brief explanation of the drawing]

FIGS. 1 and 2 are a side view and a plan view, respectively, of an embodiment of the present invention, and FIGS. 3 to 6 are explanatory diagrams of its operation. C, ~C2...Commutator segment, S...Slit, R
, ~R3... Negative pressure resistor, B,, &... Brush. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1 A negative pressure resistor having a high resistance value when no pressure is present and a low resistance value when pressurized is placed in the slit so as to contact the adjacent commutator segment, and the negative pressure resistor is moved over this negative pressure resistor. A commutator in which brushes are arranged so as to reduce the resistance value of the negative pressure resistor by contact pressure of the brush with the negative pressure resistor when the brush passes through the slit.