JP2020068653A - Electric contact device and rotating electric machine - Google Patents

Abstract

To provide a technique capable of obtaining an effect of reducing electromagnetic noise generated during arc discharge in an electric contact device in a wide frequency band.SOLUTION: A rotating electric machine 1 includes an electric contact device 30 having a high-potential side contact and a low-potential side contact having mutually different electric potentials, and all of a plurality of commutator pieces 32 and two brushes 35 and 36 constituting the electric contact device 30 are composed of zinc as a low boiling material with a boiling point below 2562°C.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electric contact device and a rotating electric machine.

  In Patent Document 1 below, in a commutator motor as a rotating electric machine, among electromagnetic noises caused by arc discharge generated between a commutator piece and a brush, it is particularly desirable to reduce impulsive electromagnetic noise generated at arc extinction. Is disclosed. In this technique, the arc voltage is increased by providing the commutator element with a layer of zinc or an alloy containing zinc.

JP, 2002-171724, A

  However, when the technique disclosed in Patent Document 1 is used, the effect of reducing electromagnetic noise obtained in a high frequency band exceeding 100 MHz, for example, is smaller than the effect of reducing electromagnetic noise obtained in a low frequency band. There's a problem. Therefore, in designing a rotating electric machine, a technique for obtaining a sufficient effect of reducing electromagnetic noise not only in a low frequency band but also in a wide frequency band up to a high frequency band is desired.

  Further, the above-described problem may occur not only in a rotating electric machine such as a commutator motor but also in various devices such as an electromagnetic relay having an electric contact device that generates electromagnetic noise due to arc discharge.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique capable of obtaining an effect of reducing electromagnetic noise generated during arc discharge in a wide frequency band in an electric contact device.

One aspect of the present invention is
The high potential side contact (32, 35) and the low potential side contact (32, 36) having different potentials from each other are provided, and the high potential side contact and the high potential side contact can be contacted and separated from each other. The electric contact device (30, 130, 230, 330, 430, 430, 430, 430, 430, 430, 430, 430, 430, 430, 430, 430, 530, 630, 730, 830),
It is in.

Another aspect of the invention is
The high potential side contact (32, 35) and the low potential side contact (32, 36) having different potentials from each other are provided, and the high potential side contact and the high potential side contact can be contacted and separated from each other. The electrical contact device (30, 130, 230, 330, which is constituted by a low boiling point material having a boiling point lower than 2562 ° C. or a mixed material containing the low boiling point material, one of the low potential side contacts 430),
It is in.

  In the above electrical contact device, an arc is formed by the vapor of the low boiling point material during arc discharge when the high potential side contact and the low potential side contact are contacted and separated. At this time, both or one of the high-potential side contact and the low-potential side contact contains a low boiling point material having a boiling point lower than 2562 ° C. which is the boiling point of copper generally used as a material for the contact. Therefore, as compared with the case of using copper as the material of the contact, by increasing the vapor density during arc discharge and suppressing the speed change of electrons to be small, the arc is maintained longer and the time change rate of the arc voltage is kept small. be able to.

  Further, the inventor of the present invention has found that among the impulse type electromagnetic noise generated at the start and end of the arc discharge and the burst type electromagnetic noise continuously generated at the time of arc discharge, particularly the burst type electromagnetic noise in a high frequency band exceeding 100 MHz. Focusing on the fact that electromagnetic noise is likely to increase, the inventors have diligently studied a technique for reducing this electromagnetic noise.

  As a result, the inventor of the present invention, by using the above-mentioned low boiling point material or mixed material for both or one of the high potential side contact and the low potential side contact involved in contact and opening, arc discharge particularly in the high frequency band. We succeeded in finding that the time variation rate of the arc voltage can be kept small in the discharge continuation section from the start to the end, which is effective in reducing the bursty electromagnetic noise. . Therefore, not only the low frequency band but also a wide frequency band up to the high frequency band, a sufficient reduction effect of electromagnetic noise generated during arc discharge can be obtained.

  As described above, according to each of the above aspects, it is possible to provide the technique capable of obtaining the effect of reducing the electromagnetic noise generated during arc discharge in the electrical contact device in a wide frequency band.

  In the claims and the means for solving the problems, reference numerals in parentheses indicate the corresponding relationship with the specific means described in the embodiments described later, and limit the technical scope of the present invention. Not a thing.

FIG. 3 is a cross-sectional view of the rotary electric machine according to the first embodiment taken along the axial direction of the shaft. FIG. 3 is a cross-sectional view schematically showing the configuration of the electrical contact device of the first embodiment. FIG. 3 is a development view showing a state where a plurality of commutator pieces of the commutator in FIG. 2 are developed in a plane shape. FIG. 4 is a development view showing a state during arc discharge in FIG. 3. Sectional drawing which shows the structure of the electrical contact device of Embodiment 2 typically. Sectional drawing which shows the structure of the electrical contact device of Embodiment 3 typically. Sectional drawing which shows the structure of the electrical contact device of Embodiment 4 typically. The development view showing the state where a plurality of commutator pieces of a commutator were developed in a plane shape about the electric contact device of Embodiment 5. Sectional drawing along the axial direction of the shaft about the electromagnetic relay concerning Embodiment 6. Sectional drawing which shows the structure of the electrical contact device of Embodiment 6 typically. Sectional drawing which shows the structure of the electrical contact device of Embodiment 7 typically. Sectional drawing which shows the structure of the electrical contact device of Embodiment 8 typically. Sectional drawing which shows the structure of the electrical contact device of Embodiment 9 typically. Sectional drawing which shows the structure of the electrical contact device of Embodiment 10 typically. Sectional drawing which shows the structure of the electrical contact device of Embodiment 11 typically. Sectional drawing which shows the structure of the electrical contact device of Embodiment 12 typically. Sectional drawing which shows the structure of the electrical contact device of Embodiment 13 typically. Sectional drawing which shows the structure of the electrical contact device of Embodiment 14 typically. Sectional drawing which shows the structure of the electrical contact device of Embodiment 15 typically. FIG. 20 is a development view showing a state in which a plurality of commutator pieces of the commutator in FIG. 19 are developed in a plane shape. FIG. 21 is a development view showing FIG. 20 when arc generation is suppressed on the positive brush side. Sectional drawing which shows the structure of the electrical contact device of Embodiment 16 typically. FIG. 23 is a development view showing a state in which a plurality of commutator pieces of the commutator in FIG. 22 are developed in a planar shape when the arc generation is suppressed on the positive brush side. Sectional drawing which shows the structure of the electrical contact device of Embodiment 17 typically. FIG. 25 is a development view showing a state in which a plurality of commutator pieces of the commutator in FIG. 24 are developed in a plane shape when the arc generation is suppressed on the positive brush side. Sectional drawing which shows the structure of the electrical contact device of Embodiment 18 typically. Sectional drawing which shows the structure of the electrical contact device of Embodiment 19 typically. Sectional drawing which shows the structure of the electrical contact device of Embodiment 20 typically.

  Hereinafter, embodiments of the electrical contact device will be described with reference to the drawings.

(Embodiment 1)
As shown in FIG. 1, the rotary electric machine 1 according to the first embodiment is configured as an inner rotor type motor. The rotary electric machine 1 can be used as a drive motor for various devices, such as a drive motor for an in-vehicle device, a drive motor for household electricity, and a drive motor for general industrial machinery. At this time, the rotary electric machine 1 may be configured as an electric motor, or may be configured as a motor generator having two functions of an electric motor and a generator.

  In the first embodiment, unless otherwise specified, the axial direction of the shaft 10 constituting the rotary electric machine 1 is indicated by an arrow X, the radial direction of the shaft 10 is indicated by an arrow Y, and the circumferential direction of the shaft 10 is indicated by an arrow Z. Shall be shown. Further, the rotation direction, which is one of the circumferential directions Z, is indicated by an arrow Za.

  The rotary electric machine 1 includes a cylindrical shaft 10 that is a rotating shaft, and is configured to be rotationally driven by the electric power supplied from the power source E. The rotating electric machine 1 includes a housing 2 configured by a case 3 and a cover 4, and a plurality of constituent elements for rotationally driving the shaft 10, and the housing 2 accommodates the plurality of constituent elements. There is.

  The plurality of components include a plurality of support portions 5 that rotatably support the shaft 10, a rotor 20 as a rotor, an electric contact device 30, and a magnet 40 as a stator.

  The rotor 20 is fixed to the shaft 10. The rotor 20 has an iron core 21 formed by laminating a plurality of electromagnetic steel plates, and an armature coil 22, and the armature coil 22 is wound around the iron core 21.

  The magnet 40 is fixed to the inner surface of the case 3 forming the housing 2 with a gap from the rotor 20. The magnet 40 has a function of giving a field to the armature coil 22, and is configured as a permanent magnet (S pole and N pole) for fields having polarities different from each other.

  The electrical contact device 30 includes a commutator 31 and two brushes 35 and 36.

  The commutator 31 has a plurality of commutator pieces 32 and is electrically connected to the armature coil 22. As shown in FIG. 2, in the commutator 31, the plurality of commutator pieces 32 are arranged side by side in the circumferential direction Z of the shaft 10. The two adjacent commutator pieces 32, 32 are separated from each other in the circumferential direction Z and are electrically connected to each other by the armature coil 22.

  The number of the commutator pieces 32 is not limited, and is set to an appropriate value as needed. In FIG. 2, the number of commutator pieces 32 is three for convenience of description.

  As shown in FIG. 2, each of the plurality of commutator pieces 32 has a sliding contact start portion 33 and a sliding contact end portion 34 with respect to each of the two brushes 35 and 36 when the commutator 31 rotates.

  The sliding contact start portion 33 is a portion where the commutator piece 32 first comes into sliding contact with the first brush 35 or the second brush 36. In FIG. 2, the commutator piece 32 is slidably contacted by the front end portion 32 a of the commutator piece 32 in the rotation direction Za. The starting unit 33 is configured.

  The sliding contact end portion 34 is a portion where the commutator piece 32 releases the sliding contact with the first brush 35 or the second brush 36, and in FIG. 2, the rear end portion 32b of the commutator piece 32 in the rotation direction Za. The sliding contact end portion 34 is configured by.

  Each of the two brushes 35 and 36 is a substantially rectangular brush that is electrically connected to the power source E and is in sliding contact with the plurality of commutator pieces 32 as the commutator 31 rotates. One first brush 35 is electrically connected to the positive terminal of the power source E. The other second brush 36 is electrically connected to the negative terminal of the power source E and is configured to form a pair with the first brush 35. The two brushes 35, 36 are arranged at positions displaced by 180 ° in the circumferential direction Z. Therefore, the first brush 35 can be called a “positive brush” and the second brush 36 can be called a “negative brush”.

  The first brush 35 is capable of coming into contact with and opening the plurality of commutator pieces 32. When the first brush 35 comes into contact with or separates from the plurality of commutator pieces 32, the first brush 35 is relatively arranged with respect to the plurality of commutator pieces 32 serving as a low potential side contact. It becomes a high potential side contact with high potential. The second brush 36 is capable of coming into contact with and separating from the plurality of commutator pieces 32, and when coming into contact with or separated from the plurality of commutator pieces 32, relative to the plurality of commutator pieces 32 serving as high-potential side contacts. It is a low potential side contact with low potential. As described above, each of the plurality of commutator pieces 32 can be a high-potential-side contact or a low-potential-side contact depending on the sliding contact relationship with the two brushes 35 and 36. In this case, the high-potential side contact and the low-potential side contact are constituted by the plurality of commutator pieces 32 and the two brushes 35, 36.

  In the present embodiment, all of the plurality of commutator pieces 32 and both of the two brushes 35 and 36 are made of zinc as a low boiling point material. These may be composed only of zinc, or may be composed of a mixed material containing zinc. Zinc is a low-boiling material having a boiling point of 907 ° C., which is lower than the boiling point of copper, which is generally used for brush materials, of 2562 °.

  Here, the state at the time of arc discharge will be described with reference to FIG. In addition, in this figure, for convenience of description, a plurality of commutator pieces 32 of the commutator 31 are shown in a flattened state so that the left-right direction of the drawing is the circumferential direction Z.

  As shown in FIG. 3, when two adjacent commutator pieces 32A and 32B are both in sliding contact with the first brush 35, the potential of these two commutator pieces 32A and 32B is the potential of the positive terminal of the power source E. Matches Further, when the two adjacent commutator pieces 32C and 32D are both in sliding contact with the second brush 36, the potentials of these two commutator pieces 32C and 32D match the potential of the negative terminal of the power source E.

  After that, as shown in FIG. 4, one of the two commutator pieces 32A and 32B that were in sliding contact with each other is separated from the first brush 35 by the rotation of the commutator 31 in the rotation direction Za. Then, an arc A is generated between the commutator piece 32A and the first brush 35. For this arc A, the first brush 35 serves as an anode and the commutator piece 32A serves as a cathode. Therefore, the first brush 35 becomes the anode brush 37P.

  Further, when one of the two commutator pieces 32C, 32D that are in sliding contact with each other is separated from the second brush 36 by the rotation of the commutator 31 in the rotation direction Za, the commutator piece 32C and the commutator piece 32C are separated from each other. An arc A is generated between the second brush 36 and the second brush 36. For this arc A, the second brush 36 serves as a cathode and the commutator piece 32C serves as an anode. Therefore, the second brush 36 becomes the cathode brush 37N.

  At this time, all of the plurality of commutator pieces 32 and both of the two brushes 35 and 36 are made of zinc having a boiling point lower than that of copper, as described above. Therefore, as compared with the case of using copper, by increasing the vapor density at the time of arc discharge and suppressing the speed change of electrons to be small, the arc A can be maintained long and the time change rate of the arc voltage can be suppressed to be small. . In particular, the use of zinc having a boiling point significantly lower than that of copper can enhance the effect of densifying the metal vapor of zinc during arc discharge.

  Further, the present inventor conducted a study paying attention to the fact that bursty electromagnetic noise is apt to increase particularly in a high frequency band exceeding 100 MHz. As a result, the high-potential side contact and the low-potential side contact and separation involved. By composing both of the plurality of commutator pieces 32 and both of the two brushes 35 and 36 as both contacts, with zinc, in the high frequency band, the arc continues in the discharge continuation section from the start to the end of the arc discharge. It was confirmed that the state in which the time change rate of the voltage was suppressed to a small level could be maintained, which was effective in reducing the bursty electromagnetic noise.

  According to the electrical contact device 30 described above, with respect to the sliding contact between the plurality of commutator pieces 32 and the two brushes 35 and 36, the sliding contact (also referred to as “contact”) and the sliding contact release (“open”). It is also possible to obtain a sufficient effect of reducing electromagnetic noise that occurs during arc discharge in the case of a wide frequency band not only in the low frequency band but also in the high frequency band.

  Further, as a measure against electromagnetic noise, it is possible to omit a filter constituted by a coil, a capacitor, etc., an electromagnetic shield made of metal, an electromagnetic noise reducing element such as a rotor earth, and the cost of the apparatus can be reduced.

  As described above, it is preferable that zinc is contained in both the anode brush 37P and the cathode brush 37N, but if necessary, the effect of reducing bursty electromagnetic noise during continuous discharge is relatively high. Zinc may be contained only in the cathode brush 37N, and the anode brush 37P may be made of copper containing no zinc. That is, when zinc is contained only in the cathode brush 37N whose polarity for the arc A is the cathode, compared with the case where zinc is contained only in the anode brush 37P whose polarity for the arc is the anode, the discharge is continued. The effect of reducing the bursty electromagnetic noise is enhanced.

In the case of a mixed material, the proportion of zinc contained in this mixed material is preferably 25% by weight or more. This can enhance the effect of densifying the vapor of the low boiling point material during arc discharge.
Of course, if the desired effect is obtained, it is also possible to use a mixture having a zinc content of less than 25% by weight.

  Further, although the effect is reduced as compared with the electrical contact device in which all of the plurality of commutator pieces 32 and both of the two brushes 35 and 36 contain zinc, when an acceptable effect is obtained, a plurality of Structure in which at least one of the commutator pieces 32 of 1. contains zinc and both of the two brushes 35 and 36 contain zinc, and at least one of the plurality of commutator pieces 32 contains zinc, and 2 A structure in which one of the two brushes 35 and 36 contains zinc, or a structure in which one of the two brushes 35 and 36 does not contain zinc in any of the plurality of commutator pieces 32 and zinc is contained You can also do it.

  In the first embodiment described above, the rotary electric machine 1 which is an inner rotor type motor is exemplified, but the brush arrangement structure in this rotary electric machine can also be applied to an outer rotor type motor.

  Hereinafter, other embodiments related to the first embodiment will be described with reference to the drawings. In other embodiments, the same elements as those of the above-described first embodiment are designated by the same reference numerals, and the description of the same elements will be omitted.

(Embodiment 2)
As shown in FIG. 5, in the electrical contact device 130 of the second embodiment, the electrical contact device 30 of the first embodiment is used for all the configurations of the plurality of commutator pieces 32 and the configurations of both of the two brushes 35 and 36. It is different from the one. Only this difference will be described below.
Other configurations are similar to those of the first embodiment.

  In all of the plurality of commutator pieces 32, only the rear end portion 32b and the sliding contact end portion 34 are made of zinc, which is a low boiling point material, and the remaining portions have electric resistivity higher than that of zinc. Composed of low copper.

  Each of the two brushes 35 and 36 is made of a mixed material mainly containing zinc, which is a low boiling point material, and carbon. In each of the two brushes 35, 36, the mixed material is divided into two regions in the circumferential direction Z, zinc is arranged in one region 35a, 36a, and carbon is arranged in the other region 35b, 36b. ing.

  The term "main body" as used herein is intended to exclude trace components, impurities, and the like that are mixed in the materials that form the mixed material. For this reason, the mixed material of the present embodiment is substantially composed of only zinc and carbon, except for the trace components and impurities.

  The carbon functions as a lubricant that can reduce the sliding resistance between each of the two brushes 35 and 36 and the plurality of commutator pieces 32. In this case, in each of the two brushes 35 and 36, it is preferable to arrange carbon on the front side of the commutator 31 in the rotation direction Za so that the carbon first contacts the commutator piece 32.

  According to the electrical contact device 130 of the second embodiment, both of the two brushes 35 and 36 are mainly composed of zinc which is a low boiling point material and carbon which is a lubricant so that no other material is contained. By doing so, the effect of densifying the vapor of the low boiling point material during arc discharge can be kept high.

  Further, among the respective parts of the commutator piece 32, the part using zinc can be minimized only by the sliding contact end part 34, which is effective in suppressing the manufacturing cost low. Further, by constructing the portion of the commutator piece 32 other than the sliding contact end portion 34 from copper having a lower electrical resistivity than zinc, it is effective to improve the efficiency of the rotating electric machine 1.

  Furthermore, the cost of the device can be kept low by using relatively inexpensive carbon as the lubricant.

  Note that the lubricant is not limited to carbon, and a lubricant other than carbon can be used if necessary. In addition, a material other than copper can be used for parts other than the sliding contact end part 34 as long as the material has a lower electrical resistivity than zinc.

  In addition, the same operational effects as those of the first embodiment are obtained.

  As a modification particularly related to the electrical contact device 130 of the second embodiment, a structure in which a portion using zinc is only the sliding contact start portion 33, or a portion using zinc is in sliding contact with the sliding contact start portion 33. It is also possible to adopt a structure having both of the end portions 34.

(Embodiment 3)
As shown in FIG. 6, the electrical contact device 230 of the third embodiment is different from that of the electrical contact device 130 of the second embodiment in all the configurations of the plurality of commutator pieces 32. Only this difference will be described below.
Other configurations are similar to those of the second embodiment.

  Each of the plurality of commutator pieces 32 is configured such that the radial length of the rear end portion 32b gradually decreases toward the rear end surface. Therefore, in each of the plurality of commutator pieces 32, the sliding contact end portion 34 is arranged at a position moved to the front end portion 32a side from the rear end portion 32b. Even with such a configuration, the same operational effect as that of the second embodiment can be obtained.

  As a modification particularly related to the electrical contact device 230 of the third embodiment, a structure in which a portion using zinc is only the sliding contact start portion 33, or a portion using zinc is in sliding contact with the sliding contact start portion 33. It is also possible to adopt a structure having both of the end portions 34.

(Embodiment 4)
As shown in FIG. 7, the electrical contact device 330 of the fourth embodiment is different from that of the electrical contact device 130 of the second embodiment in all the configurations of the plurality of commutator pieces 32. Only this difference will be described below.
Other configurations are similar to those of the second embodiment.

  Each of the plurality of commutator pieces 32 is configured such that the radial length of the front end portion 32a gradually decreases toward the front end surface, and the radial length of the rear end portion 32b extends toward the rear end surface. It is configured to gradually decrease as it goes. Therefore, in each of the plurality of commutator pieces 32, the sliding contact start portion 33 is arranged at a position moved to the rear end portion 32b side from the front end portion 32a, and the sliding contact end portion 34 is located farther than the rear end portion 32b. It is arranged at a position moved to the front end portion 32a side. Even with such a configuration, the same operational effect as that of the second embodiment can be obtained.

(Embodiment 5)
As shown in FIG. 8, the electrical contact device 430 according to the fifth embodiment is the same as the electrical contact device 30 according to the first embodiment with respect to the point including a plurality of pressure equalizing lines 38 and the number and arrangement of the brushes 35 and 36. Is different from Only this difference will be described below.
Other configurations are similar to those of the first embodiment.

  Each of the plurality of pressure equalizing wires 38 is configured to electrically connect two of the plurality of commutator pieces 32. According to this configuration, it is possible to suppress the torque fluctuation by finely switching the voltage and reducing the pulsation.

  Two brushes 35 and 36 are provided. Among these, the two brushes 35 and 36, whose sliding contact with the commutator piece 32 ends immediately before the arc A occurs, are made of zinc as a low boiling point material. Such a configuration is effective in reducing burst-type electromagnetic noise by increasing the vapor density during arc discharge and suppressing the change in electron velocity.

  In addition, the same operational effects as those of the first embodiment are obtained.

(Embodiment 6)
As shown in FIG. 9, the electrical contact device 530 of the sixth embodiment is different from the electrical contact device 30 of the first embodiment in that it is provided in the electromagnetic relay 101 as a relay. Only this difference will be described below.

  In the sixth embodiment, unless otherwise specified, the axial direction of the shaft 110 that constitutes the electromagnetic relay 101 is indicated by an arrow X, and the radial direction of the shaft 110 is indicated by an arrow Y.

  The case 102 of the electromagnetic relay 101 includes a first case 102a, a second case 102b, and a third case 102c interposed between the first case 102a and the second case 102b. The third case 102c has a through hole 103 through which a part of each of a movable core 106 and a shaft 110 described later can be inserted.

  In a space surrounded by the first case 102a and the third case 102c, a mover 104 having two movable contacts 104a, two fixed terminals 105 having fixed contacts 105a, and a movable core 106 made of a magnetic metal material. And are housed.

  One of the two movable contacts 104a is arranged to face one of the two fixed contacts 105a in the axial direction X, and the other of the two movable contacts 104a is arranged of the two fixed contacts 105a. It is arranged to face the other side in the axial direction X.

  Here, the electric contact device 530 includes two movable contacts 104a as high-potential side contacts, two fixed contacts 105a as low-potential side contacts capable of contacting and separating from the two movable contacts 104a, and It is composed by.

  In a space surrounded by the second case 102b and the third case 102c, an exciting coil 107 that forms a magnetic field when energized, and a fixed core 108 made of a magnetic metal material and arranged inside the exciting coil 107 in the radial direction Y. And a return spring 109 interposed between the movable core 106 and the fixed core 108.

  The return spring 109 constantly elastically biases the movable core 106 so as to separate it from the fixed core 108 in the axial direction X.

  The shaft 110 is fixed to the movable element 104 and the movable core 106, and an end portion of the shaft 110 opposite to the movable element 104 with the movable core 106 interposed therebetween extends inside the fixed core 108 to the vicinity of the exciting coil 107. .

  When the exciting coil 107 is not energized, the mover 104 is arranged at a position separated from the fixed terminal 105 in the axial direction X according to the elastic biasing force of the return spring 109. At this time, the mover 104 is separated from the two fixed terminals 105, and the two movable contacts 104a and the two fixed contacts 105a are separated from each other, so that the energization is cut off.

  On the other hand, when the exciting coil 107 is energized, the movable core 106 is attracted toward the fixed core 108 side by the electromagnetic attraction force against the elastic biasing force of the return spring 109. At this time, the mover 104 moves downward in FIG. 9 toward the two fixed terminals 105, and the two movable contacts 104a and the two fixed contacts 105a come into contact with each other to be energized.

  As shown in FIG. 10, all of the two movable contacts 104a and the two fixed contacts 105a of the electric contact device 530 are made of zinc as a low boiling point material. Note that, in FIG. 10, only one movable contact 104a and one fixed contact 105a are shown for convenience of description. Similar to the structure of the electric contact device 30 described above, this structure also has a structure that "both the high potential side contact and the low potential side contact are made of a low boiling point material having a boiling point lower than 2562 ° C." Equivalent to.

  According to the electric contact device 530, similarly to the case of the electric contact device 30 of the first embodiment, the movable contact 104a and the fixed contact 105a as both the high-potential side contact and the low-potential side contact involved in contact and separation are provided. Since both of them are made of zinc, the arc A is formed by the metal vapor of zinc during arc discharge when the movable contact 104a and the fixed contact 105a are contacted and separated from each other. At this time, as compared with the case where copper is used as the material of the contact, the time change rate of the arc voltage can be suppressed to be small. This makes it possible to reduce bursty electromagnetic noise during continuous discharge.

(Embodiment 7)
As shown in FIG. 11, the electrical contact device 630 of the seventh embodiment differs from the electrical contact device 530 of the sixth embodiment in the configuration of the two fixed contacts 105a. Only this difference will be described below.
Other configurations are similar to those of the sixth embodiment.

  Each of the two fixed contacts 105a has a coating layer 105b made of zinc on the contact surface, and the other portions are made of copper.

  According to the above electrical contact device 630, the device cost can be kept low by reducing the amount of zinc used in the two fixed contacts 105a.

  In addition, the same operational effects as the sixth embodiment are achieved.

(Embodiment 8)
As shown in FIG. 12, the electrical contact device 730 of the eighth embodiment differs from that of the electrical contact device 530 of the sixth embodiment in the configuration of the two movable contacts 104a and the two fixed contacts 105a. Only this difference will be described below.

  Each of the two movable contacts 104a has a coating layer 104b made of zinc on the contact surface, and the other parts are made of copper. Each of the two fixed contacts 105a has a coating layer 105b made of zinc on the contact surface, and the other parts are made of copper.

  According to the electric contact device 730, the device cost can be kept low by reducing the amount of zinc used in both the two movable contacts 104a and the two fixed contacts 105a.

  In addition, the same operational effects as the seventh embodiment are achieved.

(Embodiment 9)
As shown in FIG. 13, the electrical contact device 830 of the ninth embodiment differs from that of the electrical contact device 730 of the eighth embodiment in that one movable contact 104a is assigned to two fixed contacts 105a. There is. Only this difference will be described below.

  According to the electric contact device 830 described above, the device cost can be kept low by reducing the number of the movable contacts 104a.

  In addition, the same effect as that of the eighth embodiment is obtained.

  In the electrical contact device 30 of Embodiment 1 described above, both of the plurality of commutator pieces 32 and both of the two brushes 35 and 36 are made of zinc as a low boiling point material, so that zinc is not discharged during arc discharge. Although it is possible to reduce the electromagnetic noise by densifying the metal vapor of No. 3, when the rotating electric machine 1 is operated with a large current, there may be a problem that the effect of reducing the electromagnetic noise is lowered. Therefore, there is a demand for a technique for suppressing the reduction of the electromagnetic noise reduction effect under the condition of a large current.

  As a result of earnest studies on the factors that reduce the electromagnetic noise reduction effect under the condition of a large current, the present inventor melted the low boiling point material, and the low boiling point material on the surface as the sliding contact surface of each commutator piece 32. There is a problem that adhered substances that are oxides (for example, zinc oxide when the low boiling point material is zinc) are adhered, and the following Embodiments 10 to 14 are effective in solving this problem. I found it.

(Embodiment 10)
As shown in FIG. 14, the electrical contact device 30A of the tenth embodiment is applied to the rotary electric machine 1 of FIG. 1 as a modification of the electrical contact device 30 of the first embodiment. The electric contact device 30A provides the two brushes 35 and 36 with a function of physically removing the adhered matter fixed to the surface of each commutator piece 32, thereby reducing the electromagnetic noise under the condition of a large current. Is configured to suppress the lowering of.

  In order to achieve this configuration, in the electric contact device 30A, the two brushes 35 and 36 contain an abrasive together with zinc. The electric contact device 30A has a sliding contact structure (hereinafter, referred to as "first sliding contact structure") in which the two brushes 35 and 36 are in sliding contact with each of the plurality of commutator pieces 32 via an abrasive.

  As the abrasive, it is preferable to use a material having a hardness higher than that of the fixed matter fixed on the surface of each commutator piece 32. In the case of the present embodiment, typically, silicon carbide, mesocarbon powder, copper-manganese alloy, or the like can be used as a material having a hardness higher than that of solid zinc oxide. Since silicon carbide has relatively high polishing performance, it is preferable to use silicon carbide in order to enhance the effect of preventing fixation of zinc oxide. On the other hand, in order to extend the service life, it is preferable to use mesocarbon powder or a copper-manganese alloy.

  The content ratio of the abrasive in each of the two brushes 35 and 36 is preferably 10% by weight or less. If the content ratio of the abrasive exceeds 10% by weight, the amount of zinc is relatively reduced, and it is difficult to obtain the original effect of reducing electromagnetic noise by using zinc.

  Further, when the content ratio of the abrasive is high (for example, when it exceeds 10% by weight), frictional heat generated by polishing with the abrasive is relatively increased. Then, this can be a factor such as an increase in the melting amount of zinc (that is, an increase in zinc oxide) and damage to each commutator piece 32. Therefore, it is preferable to keep the content ratio of the polishing agent low while taking into consideration the frictional heat generated by polishing with the polishing agent.

  Other configurations are similar to those of the first embodiment.

  According to the above electrical contact device 30A, when each commutator piece 32 slides in the circumferential direction Z with respect to the two brushes 35, 36 when the shaft 10 rotates in the rotational direction Za, the two brushes 35, 36 are provided. The abrasive contained in (1) is ground so as to physically scrape off the zinc oxide adhered to each commutator piece 32. Therefore, the amount of zinc oxide formed on the surface of each commutator piece 32 can be reduced. As a result, the metal vapor of zinc can be densified during arc discharge, and the electromagnetic noise reduction effect can be improved even when the rotating electrical machine 1 is operated at a large current.

  In addition, the same operational effects as those of the first embodiment are obtained.

  In a modification particularly related to the electric contact device 30A, only one of the two brushes 35 and 36 may contain the abrasive.

(Embodiment 11)
As shown in FIG. 15, the electrical contact device 30B of the eleventh embodiment is a modification of the electrical contact device 30A of the tenth embodiment. In this electrical contact device 30B, the plurality of commutator pieces 32 are all made of copper, and the two brushes 35 and 36 are each divided into two regions in the circumferential direction Z, and one region 35a is formed. , 36a are zinc-containing portions containing zinc, and the other regions 35b, 36b are zinc-free portions containing copper or carbon other than zinc. Then, the regions 35a and 36a which are zinc-containing portions contain the same abrasive as in the case of the electrical contact device 30A.

  Other configurations are similar to those of the tenth embodiment.

  According to the electric contact device 30B described above, when the two brushes 35 and 36 are in sliding contact with the respective commutator pieces 32, as in the case of the electric contact device 30A, they are included in the regions 35a and 36a of the two brushes 35 and 36. The zinc oxide adhered to each commutator piece 32 can be ground so as to be physically scraped off by the abrasive material provided.

  In addition, the same operational effects as the tenth embodiment are obtained.

(Embodiment 12)
As shown in FIG. 16, the electrical contact device 30C of the twelfth embodiment is a modification of the electrical contact device 30B of the eleventh embodiment. In this electric contact device 30C, each commutator piece 32 is arranged at a position where the sliding contact end portion 34 is moved to the front end portion 32a side rather than the rear end portion 32b, and the sliding contact end portion 34 is made of zinc. And the remaining part is made of copper.

  Other configurations are similar to those of the eleventh embodiment.

  According to the electric contact device 30C described above, when the two brushes 35 and 36 are in sliding contact with the respective commutator pieces 32, as in the case of the electric contact device 30B, they are included in the regions 35a and 36a of the two brushes 35 and 36. The zinc oxide adhered to each commutator piece 32 can be ground so as to be physically scraped off by the abrasive material provided.

  In addition, the same effect as that of the eleventh embodiment is obtained.

In a modification particularly related to the electric contact devices 30B and 30C, only one of the areas 35a and 36a of the two brushes 35 and 36 may contain the abrasive.

(Embodiment 13)
As shown in FIG. 17, the electrical contact device 30D of the thirteenth embodiment is a modification of the electrical contact device 30 of the first embodiment. In this electric contact device 30D, the plated layer 32d is provided on the surface of each commutator piece 32 to make it difficult for the adhered matter to adhere, so that the effect of reducing electromagnetic noise under a high current condition is suppressed. It is configured.

  In order to achieve this configuration, in the electrical contact device 30D, the sliding contact surface of each commutator piece 32 is plated with at least one material selected from silver, nickel, and palladium. This electrical contact device 30D has a sliding contact structure in which a plating layer 32d made of at least one material of silver, nickel, and palladium is formed on each sliding contact surface of a plurality of commutator pieces 32 (hereinafter, referred to as “first 2 sliding contact structure ”).

  Other configurations are similar to those of the first embodiment.

  According to the above electrical contact device 30D, the corrosion resistance (oxidation resistance) of each commutator piece 32 can be enhanced by the plating layer 32d, and zinc oxide is generated on the sliding contact surface of each commutator piece 32. Can be prevented. Thereby, even when the rotary electric machine 1 is operated with a large current, the effect of reducing electromagnetic noise can be improved.

  In addition, the same operational effects as those of the first embodiment are obtained.

(Embodiment 14)
As shown in FIG. 18, the electrical contact device 30E of the fourteenth embodiment is a modification of the electrical contact device 30 of the first embodiment. This electrical contact device 30E reduces the melting amount of zinc, which is a low boiling point material, and makes it difficult for the adhered matter to adhere to the surface of each commutator piece 32, thereby reducing the effect of reducing electromagnetic noise under the condition of a large current. Is configured to suppress the

  In order to achieve this configuration, in the electric contact device 30E, the sliding contact area of the two brushes 35 and 36 with respect to each commutator piece 32 is increased to suppress the electric resistance during energization. This electric contact device 30E has a sliding contact structure (hereinafter, referred to as "first contact part") in which the brush 35 is in sliding contact with each of the plurality of commutator pieces 32 at a sliding contact length Lb that is 1/10 or more of the facing length La in the axial direction X. 3 sliding contact structure ”).

  Although not particularly shown, the brush 36 also has a third sliding contact structure similar to that of the brush 35. Below, only the 3rd sliding contact structure provided with respect to the brush 35 is demonstrated.

  Other configurations are similar to those of the first embodiment.

  In the third sliding contact structure, the facing length La is a length in the axial direction X at which the brush 35 faces the commutator pieces 32 so as to be slidable. On the other hand, the sliding contact length Lb is the length in the axial direction X when the facing surface 35c of the brush 35 is actually in sliding contact with the facing surface 32c of each commutator piece 32. Therefore, when the facing surface 35c of the brush 35 and the facing surface 32c of each commutator piece 32 are in a substantially parallel relationship, the sliding contact length Lb matches the facing length La. The smaller the inclination angle of the facing surface 35c with respect to the facing surface 32c, the larger the sliding contact length Lb, and the larger the inclination angle of the facing surface 35c with respect to the facing surface 32c, the smaller the sliding contact length Lb.

  A pressing spring 39 is provided inside the brush holder 30a that accommodates the brush 35 slidably in the radial direction Y. The pressing spring 39 has an elastic function of pressing the brush 35 against each commutator piece 32. It is preferable to use a spring member such as a coil spring or a leaf spring as the pressing spring 39. By the pressing spring 39, the facing surface 35c of the brush 35 is pressed against the facing surface 32c of each commutator piece 32. If necessary, an elastic member may be used instead of the spring member as long as it can exhibit the same elastic function as the pressing spring 39.

  When the length of the facing surface 35c of the brush 35 in the circumferential direction Z is constant, the contact area between the facing surface 32c and the facing surface 35c of each commutator piece 32 is proportional to the sliding contact length Lb. As the sliding contact length Lb increases, the contact area between the facing surface 32c and the facing surface 35c of each commutator piece 32 increases, and as the sliding contact length Lb decreases, the facing surface 32c of each commutator piece 32 faces. The contact area with the surface 35c is reduced.

  The condition that the sliding contact length Lb is 1/10 or more of the facing length La is preferably satisfied when the electrical contact device 30E is finally assembled. Therefore, when the above conditions are not satisfied, it is necessary to perform a process on the brush 35 to eliminate the uneven contact of the facing surface 35c with respect to the facing surface 32c of each commutator piece 32. Here, the “single contact” means a state in which only a part of the facing surface 35c of the brush 35 serves as a sliding contact surface against the facing surface 32c.

  Therefore, for example, the facing surface 35c of the brush 35 is cut using a tool such as a cutting jig or the rotating electric machine 1 is actually operated, and the facing surface of the brush 35 is satisfied until the above condition is satisfied. The sliding contact length Lb with respect to the facing length La can be increased by abrading 35c.

  According to the electrical contact device 30E described above, the contact area between each of the two brushes 35 and 36 and each commutator piece 32 is set by making the sliding contact length Lb 1/10 or more of the facing length La. It can be increased to suppress the electric resistance when energized. In this case, it is possible to reduce the Joule heat and suppress the generation of zinc oxide that can adhere to the facing surface 32c of each commutator piece 32. Thereby, even when the rotary electric machine 1 is operated with a large current, the effect of reducing electromagnetic noise can be improved.

  In addition, the same operational effects as those of the first embodiment are obtained.

  In a modification particularly related to the electric contact device 30E, the third sliding contact structure may be adopted for only one of the two brushes 35 and 36.

  In another modification, a structure in which at least two of the first sliding contact structure, the second sliding contact structure, and the third sliding contact structure are combined can be adopted.

  In the above-described Embodiments 10 to 14, the case in which the adhered matter is prevented from adhering to the surface of each commutator piece 32 to suppress the reduction of the electromagnetic noise reduction effect under the condition of a large current has been exemplified. The present inventor, based on a viewpoint different from this, suppresses the occurrence of the arc itself as described in Embodiments 15 to 20 below even if the adhered matter adheres to the surface of each commutator piece 32. It was found that doing so is effective in reducing electromagnetic noise.

(Embodiment 15)
As shown in FIGS. 19 and 20, the electrical contact device 30F of the fifteenth embodiment is a modification of the electrical contact device 30 of the first embodiment. The electric contact device 30F includes an arc absorbing portion 50. The arc absorbing portion 50 is a positive brush generated when the positive brush 35 electrically connected to the positive electrode of the power source E of the two brushes 35 and 36 is released from sliding contact with the commutator piece 32. It is for absorbing the arc energy on the brush 35 side.

  The positive brush 35 is made of copper, and the negative brush 36 is made of zinc. The positive brush 35 may be made of zinc, if necessary. In this case, molten zinc is fixed as zinc oxide S on the surface of each commutator piece 32.

  The arc absorbing portion 50 is provided in a commutator piece 32 (a commutator piece 32 adjacent to the front side in the rotation direction Za) different from the commutator piece 32 with which the positive brush 35 is slidably contacted among the plurality of commutator pieces 32. The auxiliary brush 51 is in sliding contact, and the energizing member 53 provided in the bypass path 52 that electrically connects the positive brush 35 and the auxiliary brush 51.

  The auxiliary brush 51 is disposed on the front side in the rotation direction Za of the commutator 31 with respect to the positive brush 35, and the distance D in the circumferential direction Z between the auxiliary brush 51 and the positive brush 35 is the circumferential direction Z of the commutator pieces 32. Is smaller than the minimum value Cmin of the width dimension.

  The current-carrying member 53 includes at least one of a known diode, a capacitor, a snubber, and a varistor, as well as a high resistance body having a higher resistance than the positive brush 35.

  Other configurations are similar to those of the first embodiment.

  In this electric contact device 30F, the sliding contact relationship between the positive brush 35 and the plurality of commutator pieces 32 changes as shown in FIGS. 20 to 21 due to the rotation of the commutator 31 in the rotation direction Za. As shown in FIG. 21, when one commutator piece 32A of the two commutator pieces 32A, 32B slidably contacting the positive brush 35 is separated from the positive brush 35, the normal brush 35 and An arc A is generated between the commutator piece 32A (in FIG. 21, the arc A that can be generated on the positive brush 35 side is indicated by a broken line for convenience of description). On the other hand, when one of the two commutator pieces 32C and 32D that slidably contact the negative brush 36 is separated from the negative brush 36, an arc is generated between the negative brush 36 and the commutator piece 32C. A occurs.

  Here, according to the arc absorbing unit 50, a bypass current flows from the positive brush 35 side to the commutator piece 32A through the energizing member 53 and the auxiliary brush 51 immediately before the positive brush 35 is separated from the commutator piece 32A. It is possible to prevent the generation of the arc A by letting the arc energy on the side of the positive brush 35, which is the generation factor of the arc A, escape. Therefore, even when the rotating electric machine 1 is operated with a large current in a state where the zinc oxide S adheres to the surface of each commutator piece 32, the generation of the arc A itself is suppressed to reduce the electromagnetic noise. Can be improved.

  In addition, the same operational effects as those of the first embodiment are obtained.

(Embodiment 16)
As shown in FIG. 22, the electrical contact device 30G of the sixteenth embodiment is a modification of the electrical contact device 30F of the fifteenth embodiment. The electric contact device 30G includes an arc absorbing portion 50A. 50 A of arc absorption parts absorb the arc energy by the side of the positive brush 35 produced when sliding contact with the commutator piece 32 with which the positive brush 35 is sliding contact is cancel | released similarly to the arc absorption part 50 of 15th Embodiment. It is for doing.

  The arc absorbing portion 50A has a pair of two commutator pieces 32, 32 located on both sides of the commutator piece 32 on both sides in the rotation direction Za with the commutator piece 32 with which the positive brush 35 slidably contacts being sandwiched. The auxiliary brushes 51A and 51B and the diode 54 provided in the bypass path 52 that electrically connects the pair of auxiliary brushes 51A and 51B are provided. The diode 54 has an anode electrically connected to a rear side auxiliary brush 51A of the pair of auxiliary brushes 51A and 51B on the rear side in the rotation direction Za, and a cathode of the pair of auxiliary brushes 51A and 51B to the front side in the rotation direction Za. It is electrically connected to the front side auxiliary brush 51B.

  Further, in the arc absorbing portion 50A, the distance D1 in the circumferential direction Z between the front side auxiliary brush 51B and the positive brush 35 is below the minimum value Cmin of the width dimension in the circumferential direction Z of the plurality of commutator pieces 32, and the rear side. The distance D2 in the circumferential direction Z between the auxiliary brush 51A and the positive brush 35 is configured to exceed the maximum value Cmax of the width dimension of the plurality of commutator pieces 32 in the circumferential direction Z.

  Here, the smallest value of the width dimensions in the circumferential direction Z for all the commutator pieces 32 of the commutator 301 is defined as the “minimum value Cmin”, and the largest value is defined as the “maximum value Cmax”.

  Other configurations are similar to those of the fifteenth embodiment.

  As shown in FIG. 23, according to the arc absorbing portion 50A, immediately before the positive brush 35 is separated from the commutator piece 32A, the rear auxiliary brush 51A, the diode 54, and the front auxiliary brush 51B from the positive brush 35 side. Since the bypass current flows through the commutator element 32A through the arc current, it is possible to prevent the arc A from being generated by letting out the arc energy on the side of the positive brush 35, which is the cause of the arc A. Therefore, even when the rotating electric machine 1 is operated with a large current in a state where the zinc oxide S adheres to the surface of each commutator piece 32, the generation of the arc A itself is suppressed to reduce the electromagnetic noise. Can be improved.

  In addition, the same effect as that of the fifteenth embodiment is obtained.

(Embodiment 17)
As shown in FIG. 24, the electrical contact device 30H of the seventeenth embodiment is a modification of the electrical contact device 30F of the fifteenth embodiment. The electric contact device 30H includes an arc absorbing portion 50B. The arc absorbing portion 50B absorbs the arc energy on the side of the positive brush 35 generated when the sliding contact with the commutator piece 32 with which the positive brush 35 is slidingly contacted is released, similarly to the arc absorbing portion 50 of the fifteenth embodiment. It is for doing.

  The arc absorbing unit 50B has an auxiliary brush 51 similar to the arc absorbing unit 50, and a Zener diode 55 provided in a bypass path 52 that electrically connects the positive brush 35 and the auxiliary brush 51. The Zener diode 55 has an anode electrically connected to the auxiliary brush 51 and a cathode electrically connected to the positive brush 35. The Zener diode 55 is configured so that a current flows from the cathode side to the anode side when the voltage exceeds a preset voltage.

  Other configurations are similar to those of the fifteenth embodiment.

  As shown in FIG. 25, according to the arc absorbing portion 50B, immediately before the positive brush 35 is separated from the commutator piece 32A, the positive brush 35 is moved from the positive brush 35 side to the commutator piece 32A through the Zener diode 55 and the auxiliary brush 51. Since the bypass current flows, the generation of the arc A can be prevented by letting the arc energy on the side of the positive brush 35, which is the generation factor of the arc A, escape. Therefore, even when the rotating electric machine 1 is operated with a large current in a state where the zinc oxide S adheres to the surface of each commutator piece 32, the generation of the arc A itself is suppressed to reduce the electromagnetic noise. Can be improved.

  In addition, the same effect as that of the fifteenth embodiment is obtained.

(Embodiment 18)
As shown in FIG. 26, the electrical contact device 30I of the eighteenth embodiment is a modification of the electrical contact device 30F of the fifteenth embodiment. The electric contact device 30I includes an arc absorbing portion 50C. The arc absorbing portion 50C is configured such that the auxiliary brush 51 is joined to the positive brush 35 via the electric insulating layer 56 to be integrated. That is, the electric insulating layer 56 is sandwiched between the auxiliary brush 51 and the positive brush 35 in the circumferential direction Z.

  Other configurations are similar to those of the fifteenth embodiment.

  According to the electrical contact device 30I described above, by integrating the auxiliary brush 51 and the positive brush 35, the number of brushes themselves can be reduced, and the number of brush holders and spring members associated with the brushes can be reduced. It can be reduced. Further, the arc absorbing portion 50C can be downsized by bringing the auxiliary brush 51 and the positive brush 35 close to each other in the circumferential direction Z.

  In addition, the same effect as that of the fifteenth embodiment is obtained.

(Embodiment 19)
As shown in FIG. 27, the electrical contact device 30J of the nineteenth embodiment is a modification of the electrical contact device 30H of the seventeenth embodiment. The electric contact device 30J includes an arc absorbing portion 50D. The arc absorbing portion 50D is configured such that each of the pair of auxiliary brushes 51A and 51B is joined to and integrated with the positive brush 35 via the electric insulating layer 56. That is, one electric insulating layer 56 is sandwiched by the rear auxiliary brush 51A and the positive brush 35 in the circumferential direction Z, and the other electric insulating layer 56 is circumferentially Z in the front auxiliary brush 51B and the positive brush 35. It is sandwiched between and.

  Other configurations are similar to those of the seventeenth embodiment.

  According to the above electrical contact device 30J, by integrating the pair of auxiliary brushes 51A and 51B and the positive brush 35, the number of brushes can be reduced, and the number of brush holders and spring members attached to the brushes can be reduced. Therefore, the cost can be reduced. Further, by making the pair of auxiliary brushes 51A and 51B and the positive brush 35 close to each other in the circumferential direction Z, the arc absorbing portion 50D can be downsized.

  In addition, the same effect as that of the seventeenth embodiment is obtained.

  In the electric contact devices 30F, 30G, 30H, 30I, 30J, the arc absorbing parts 50, 50A, 50B, 50C, 50D may be provided on the negative brush 36 side in addition to the positive brush 35 side. As a result, the effect of reducing electromagnetic noise can be further improved. On the other hand, it is known that the electromagnetic noise caused by the arc A generated on the negative brush 36 side is smaller than the electromagnetic noise generated by the arc A generated on the positive brush 35 side, and the electromagnetic contact devices 30F, 30G, 30H, 30I, 30J have the following characteristics. In order to reduce the cost, it is preferable to provide the arc absorbing parts 50, 50A, 50B, 50C and 50D only on the positive brush 35 side.

(Embodiment 20)
As shown in FIG. 28, the electrical contact device 30K of the twentieth embodiment is a modification of the electrical contact device 30F of the fifteenth embodiment. The electric contact device 30K includes an arc absorbing portion 50E. The arc absorbing portion 50E is configured such that the sliding contact length Ma of the positive brush 35 in the circumferential direction Z exceeds the sliding contact length Mb of the negative brush 36 in the circumferential direction Z.

  Other configurations are similar to those of the fifteenth embodiment.

  According to the above electrical contact device 30K, by making the sliding contact length Ma of the positive brush 35 longer than the sliding contact length Mb of the negative brush 36, the positive brush 35 slidably contacts the two commutator pieces 32. The time for which the coil is short-circuited can be extended and the amount of arc energy consumed as heat can be increased. Therefore, even when the rotating electric machine 1 is operated with a large current in a state where the zinc oxide S adheres to the surface of each commutator piece 32, the generation of the arc A itself is suppressed to reduce the electromagnetic noise. Can be improved.

  In addition, the same effect as that of the fifteenth embodiment is obtained.

  The present invention is not limited to the above-described typical embodiments, and various applications and modifications are conceivable without departing from the object of the present invention. For example, each of the following forms to which the above-described embodiment is applied can be implemented.

  In the above-described embodiment, the case where zinc is used as the low boiling point material has been described as an example, but instead of this, a material having a boiling point lower than that of copper (for example, magnesium) can be used.

  In the above-described embodiment, the mixed material mainly composed of zinc and the lubricant has been exemplified, but the material mixed in addition to zinc is not limited to the lubricant, and if necessary, other than the lubricant may be used. You can also add ingredients.

  DESCRIPTION OF SYMBOLS 1 ... Rotating electric machine, 10 ... Shaft, 20 ... Rotor, 21 ... Iron core, 22 ... Armature coil, 30, 130, 230, 330, 430, 530, 630, 730, 830 ... Electrical contact device, 31 ... Commutator , 32, 32A, 32B, 32C, 32D ... Commutator element (high-potential side contact, low-potential side contact), 32d ... Plating layer, 33 ... Sliding contact start part, 34 ... Sliding contact end part, 35 ... First brush (High potential side contact, positive brush), 36 ... Second brush (low potential side contact, negative brush), 37N ... Cathode brush, 40 ... Magnet, 50, 50A, 50B, 50C, 50D, 50E ... Arc absorbing part, 51 ... Auxiliary brush, 51A ... Rear side auxiliary brush (auxiliary brush), 51B ... Front side auxiliary brush (auxiliary brush), 52 ... Bypass path, 53 ... Energizing member, 54 ... Diode, 55 ... Zener diode, 5 ... electrical insulating layer, 104a ... movable contact (high potential side contact), 105a ... fixed contact (low potential side contact), A ... arc, Cmin ... minimum value, Cman ... maximum value, D, D1, D2 ... interval, E ... Power supply, La ... Opposing length, Lb ... Sliding contact length, Ma, Mb ... Sliding contact length, X ... Axial direction, Z ... Circumferential direction, Za ... Rotation direction

Claims (20)

  High potential side contacts (32, 35, 104a) and low potential side contacts (32, 36, 105a) having different potentials are provided, and the high potential side contact and the high potential side contact are opened and closed. The electric contact device (30, 130, 230, 230), which is configured by a low boiling point material having a boiling point lower than 2562 ° C. or a mixed material containing the low boiling point material, 330, 430, 530, 630, 730, 830).   High potential side contacts (32, 35, 104a) and low potential side contacts (32, 36, 105a) having different potentials are provided, and the high potential side contact and the high potential side contact are opened and closed. The electrical contact device (30, 130, 130, 130), wherein one of the low-potential-side contact capable of being made of is a low-boiling material having a boiling point lower than 2562 ° C., or a mixed material containing the low-boiling material. 230, 330, 430).   The proportion of the low boiling point material in the mixed material is 25% by weight or more when at least one of the high potential side contact and the low potential side contact is made of the mixed material. Electrical contact device.   The electrical contact device according to claim 1, wherein the low boiling point material is zinc.   The electrical contact device according to any one of claims 1 to 4, wherein the mixed material is mainly composed of zinc as the low boiling point material and a lubricant.   The electrical contact device according to claim 5, wherein the lubricant is carbon. A shaft (10) which is a rotating shaft,
A rotor (20) fixed to the shaft,
An armature coil (22) wound around the iron core (21) of the rotor;
A commutator (31) electrically connected to the armature coil;
A plurality of commutator pieces (32) arranged in the circumferential direction (Z) of the shaft in the commutator;
A magnet (40) for applying a field to the armature coil,
A plurality of brushes (35, 36) electrically connected to the power source (E) and slidingly contacting the plurality of commutator pieces as the commutator rotates;
An electrical contact device according to any one of claims 1 to 6,
Equipped with
The rotating electrical machine (1), wherein the high potential side contact and the low potential side contact of the electric contact device are constituted by the plurality of commutator pieces and the plurality of brushes.   The rotating electric machine according to claim 7, wherein all of the plurality of brushes are made of the low boiling point material or the mixed material.   Each of the plurality of commutator pieces has a slide contact start portion (33) and a slide contact end portion (34) for each of the plurality of brushes when the commutator rotates, and the slide contact start portion and the slide contact start portion are provided. The rotary electric machine according to claim 7, wherein at least one of the sliding contact end portions is made of the low boiling point material or the mixed material.   The rotary electric machine according to claim 7, wherein at least one of the plurality of brushes contains an abrasive and is configured to be in sliding contact with each of the plurality of commutator pieces via the abrasive.   The rotary electric machine according to claim 10, wherein the abrasive is made of at least one material of silicon carbide, mesocarbon powder, and copper-manganese alloy.   The rotary electric machine according to claim 10 or 11, wherein the content ratio of the abrasive is 10% by weight or less.   The plating layer (32d) made of at least one material of silver, nickel, and palladium is formed on each of the sliding contact surfaces of the plurality of commutator pieces, and the plating layer (32d) is formed. The rotating electric machine described in.   At least one of the plurality of brushes is slidably in contact with each of the plurality of commutator pieces in a sliding contact length (Lb) that is 1/10 or more of the opposing length (La) in the axial direction (X). ), The rotary electric machine according to any one of claims 7 and 10 to 13 configured to be in sliding contact with each of the plurality of commutator pieces.   When the brush electrically connected to the positive electrode of the power source among the plurality of brushes is the positive brush (35), sliding with the commutator piece with which the positive brush is in sliding contact with the plurality of commutator pieces The rotary electric machine according to claim 7, further comprising an arc absorbing portion (50, 50A, 50B, 50C, 50D, 50E) that absorbs the arc energy on the positive brush side generated when the contact is released. The arc absorbing portion includes an auxiliary brush (51) slidingly contacting a commutator piece different from the commutator piece slidingly contacting the positive brush among the plurality of commutator pieces, the positive brush, and the auxiliary brush. And a current-carrying member (53) provided in a bypass path (52) for electrically connecting
The auxiliary brush is arranged on the front side in the rotation direction (Za) of the commutator with respect to the positive brush, and the interval (D) in the circumferential direction between the auxiliary brush and the positive brush is the plurality of commutator pieces. Is smaller than the minimum value (Cmin) of the above-mentioned circumferential width dimension,
The rotating electric machine according to claim 15, wherein the current-carrying member is composed of at least one of a high resistance body having a resistance higher than that of the positive brush, a diode, a capacitor, a snubber, and a varistor.   17. The energizing member is constituted by a Zener diode (55) as the diode, an anode of which is electrically connected to the auxiliary brush and a cathode of which is electrically connected to the positive brush. Rotating electric machine.   The rotary electric machine according to claim 16 or 17, wherein the auxiliary brush is joined to and integrated with the positive brush via an electrically insulating layer (56). The arc absorbing portion is in sliding contact with two commutator pieces located on both sides in the rotation direction (Za) of the commutator with the commutator piece with which the positive brush is in sliding contact being sandwiched among the plurality of commutator pieces. A pair of auxiliary brushes (51A, 51B) and a bypass auxiliary path (52) electrically connecting the pair of auxiliary brushes, the anode of which is the rear side auxiliary brush on the rear side in the rotation direction of the pair of auxiliary brushes. A diode (54) electrically connected to (51A) and having a cathode electrically connected to the front side auxiliary brush (51B) on the front side in the rotation direction of the pair of auxiliary brushes;
The circumferential distance (D1) between the front auxiliary brush and the positive brush is less than the minimum value (Cmin) of the circumferential width dimension of the plurality of commutator pieces, and the rear auxiliary brush is 16. The circumferential gap (D2) between the positive brush and the positive brush is configured to exceed a maximum value (Cmax) of the width dimension of the commutator pieces in the circumferential direction. Rotating electric machine.   When the brush electrically connected to the negative electrode of the power source among the plurality of brushes is a negative brush (36), the arc absorbing portion has a sliding contact length (Ma) in the circumferential direction of the positive brush. The rotary electric machine according to any one of claims 15 to 19, which is configured to exceed a sliding contact length (Mb) of the negative brush in the circumferential direction.

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