JP2011061976A - Dc motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly durable DC motor capable of supplying a large current to an armature coil while preventing the occurrence of arc sparks without constructing a complicated control circuit. <P>SOLUTION: The DC motor includes a plurality of armature coils 2 to which drive current for rotating a rotor shaft 4 flows, field magnets 51 generating a magnetic field flux acting on the armature coils 2, a coil terminal 32 which is conductively connected to both ends of the armature coil 2, a pair of positive and negative conductive contactors 7 which are conductively connected to a DC power supply E and are intermittently brought into conductive contact with the coil terminal 32, and a magnetic field generation unit 6 forming a magnetic field between a pair of magnetic poles facing across contact parts of the coil terminal 32 and the conductive contactors 7. The coil terminal 32 and the conductive contactors 7 are brought into contact with each other and are separated each other in the magnetic field by the magnetic field generation unit 6 while they relatively rotate with the rotor shaft 4 as a center. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a DC motor suitable for use as a vehicle drive source, and more particularly to a DC motor capable of suppressing the occurrence of arc sparks.

  In recent years, the spread of hybrid vehicles using both a prime mover (internal combustion engine) and an electric motor has been remarkable. Such hybrid vehicles also have a parallel type in which both a prime mover and an electric motor are used alternately as a wheel drive source, and a series type in which the prime mover is exclusively used for power generation to obtain the drive power of the motor. There is also an increasing trend in electric vehicles that drive electric motors for driving by using stored electric power from batteries and electric power generated by fuel cells without being installed.

  On the other hand, as an electric motor, a DC motor driven by a DC power source and an AC motor driven by an AC power source are known. In a DC motor using a commutator and a brush, a commutator piece made of copper or the like and carbon are used. In addition to the problem of excessive wear due to sliding contact with the brush, there is a problem of generating sparks due to noise and arc discharge, and it is not possible to make a large amount of current due to the energization restriction by the carbon brush, so it can be made brushless A complicated electronic circuit must be constructed by using a large number of transistors.

  For this reason, in a hybrid vehicle, an electric vehicle, a fuel cell vehicle, and the like, an AC motor is used as an electric motor, and an AC motor is driven by converting a DC power source into an AC power source by an inverter (for example, Patent Document 1).

JP 2006-333552 A

  However, according to a vehicle using an AC motor (AC servo motor) as a driving source for traveling, there is a problem that an expensive inverter and a complicated control device are required to convert DC power into AC power, resulting in high cost. is there.

  The present invention has been made in view of the above circumstances, and its purpose is to supply a large current to the armature coil while suppressing the occurrence of arc sparks without constructing a complicated control circuit. An object of the present invention is to provide a DC motor with good durability that can be used.

In order to achieve the above object, the present invention
A plurality of armature coils through which a driving current for rotating the rotor shaft flows, a field system that generates a field flux acting on the armature coils, and coil terminals that are conductively connected to both ends of the armature coils; A magnetic field is formed between a pair of positive and negative conductive contacts that are conductively connected to a DC power source and intermittently conductively contact the coil terminal, and a pair of magnetic poles facing each other across the contact portion of the coil terminal and the conductive contact A DC motor , wherein the coil terminal and the conductive contact are in contact with and separated from each other in the magnetic field generated by the magnetic field generation unit while relatively rotating around the rotor axis ,
The coil terminal and the conductive contact are in conductive contact via a semiconductive lubricant that exhibits electrical conductivity under pressure and exhibits electrical insulation under no pressure,
The semiconductive lubricant is characterized in that solid particles having conductivity are dispersed in a lubricating oil having lubricity .

  In addition, a pressure spring that presses the conductive contact against the conductive contact surface of the coil terminal is provided.

  According to the direct current motor according to the present invention, a coil terminal that is conductively connected to both ends of the plurality of armature coils, a pair of positive and negative conductive contacts that are conductively connected to the DC power source and intermittently conductively contact the coil terminal, A magnetic field generating unit that forms a magnetic field between a pair of magnetic poles facing each other across a contact portion between the coil terminal and the conductive contact, while the coil terminal and the conductive contact rotate relatively around the rotor axis, Since it is configured to contact and separate within the magnetic field generated by the magnetic field generating unit, the arc spark generated between the coil terminal and the conductive contact can be applied to the arc spark to blow out the arc spark. For this reason, it can be set as a highly safe motor, generation | occurrence | production of the electrical noise by arc discharge can be suppressed, and the bad influence to other electronic devices can be prevented.

  In addition, since a pressure spring that presses the conductive contact against the conductive contact surface of the coil terminal is provided, contact failure between the conductive contact and the coil terminal can be prevented while preventing contact failure between the conductive contact and the coil terminal. A large drive current can be supplied to the armature coil.

  In addition, since the coil terminal and the conductive contact are in conductive contact via the semiconductive lubricant, wear due to sliding contact between the coil terminal and the conductive contact can be suppressed, and maintenance-free operation can be achieved.

1 is a longitudinal sectional view showing a DC motor according to the present invention. Schematic plan view showing the structure of the armature in the motor The perspective view which shows the arrangement | positioning part of an armature coil Partial expanded sectional view which shows the arrangement | positioning part of an armature coil Schematic bottom view showing the structure of the field system Enlarged sectional view showing the contact portion between the coil terminal and the conductive contact XX sectional view of FIG. Explanatory drawing showing the positional relationship between the armature coil and the field magnet Partial enlarged view of FIG.

  Hereinafter, preferred embodiments of a DC motor according to the present invention will be described with reference to the drawings. First, in FIG. 1, the direct current motor is different from a general DC motor in that a stator Sm is an armature and a rotor Rm is a field system.

  The stator Sm is fixed to the inside of the iron core 1, a ring-shaped iron core 1 fixed to an outer cylinder (not shown), a plurality of armature coils 2 arranged at a predetermined interval in the circumferential direction of the iron core 1. The commutator 3 is provided. Among these, the commutator 3 is configured by fixing coil terminals 32 electrically connected to both end portions of the armature coil 2 to a ring-shaped insulating plate 31 made of an electrical insulator such as mica or plastic. The insulating plate 31 is fixed inside the iron core 1 in a fitted state. In addition, the coil terminals 32 are arranged at equal intervals in the circumferential direction of the insulating plate 31, and each tip portion thereof protrudes from the inner peripheral surface of the insulating plate 31.

  In this example, 36 armature coils 2 and coil terminals 32 are provided in the circumferential direction of the iron core 1 as shown in FIG. 2, and one end of each of the two adjacent armature coils 2 and 2 is provided. It is conductively connected to one coil terminal 32 located between the two. Accordingly, all the armature coils 2 are in a conductive state via the coil terminals 32.

  As shown in FIGS. 3 and 4, the ring-shaped iron core 1 is formed with slits 1 a and 1 b radially extending from the outer peripheral surface to the inner peripheral surface at a predetermined pitch. And the armature coil 2 is comprised by winding the conducting wire by which the insulating film was given to the circumference | surroundings of each core part 1c by making between the adjacent slits 1a and 1b the core part 1c. 3 shows the iron core 1 in which the slits 1a and 1b are formed on one side, but actually, the iron core 1 as shown in FIG.

  On the other hand, in FIG. 1, the rotor Rm includes a rotor shaft 4 that is rotatably supported by a not-shown outer trunk via a bearing, and two rotor disks 5 fixed to the rotor shaft 4. The two rotor disks 5 are arranged opposite to each other with the iron core 1 of the stator Sm sandwiched in the axial direction of the rotor shaft 4. 51 is fixed. The field magnet 51 is a permanent magnet that generates a field flux necessary for rotating the rotor shaft 4, and one of the magnetic poles thereof is oriented to the armature coil 2 side.

  As is apparent from FIG. 5, in this example, six field magnets 51 are incorporated in the two rotor disks 5 facing each other, and these field magnets 51 are arranged at equal intervals in the circumferential direction of the rotor disk 5. Has been. The field magnet 51 may be a metal magnet or a sintered magnet, but a neodymium magnet having a large coercive force is preferably used. Moreover, the magnetic poles on the exposed surface of the field magnet 51 directed to the armature coil 2 side are different from each other. That is, paying attention to one field magnet 51, when the exposed surface is an N pole, the exposed surface of the field magnet 51 located on both sides thereof is an S pole, and along the circumferential direction of the rotor disk 5. N poles and S poles appear alternately.

  As is clear from FIGS. 1 and 6, a magnetic field generating unit 6 positioned inside the iron core 1 constituting the stator Sm is interposed between the rotor disks 5 and 5 facing each other. In the magnetic field generating unit 6, ring-shaped magnetic pieces 62, 62 made of a magnetic material are disposed on both magnetic pole sides with a ring-shaped permanent magnet 61 that surrounds the rotor shaft 4, and one side of each of the magnetic pieces 62 is different. It is set as the structure which opposes as a pair of magnetic pole (N pole and S pole). The permanent magnet 61 may be a metal magnet or a sintered magnet, like the field magnet 51, but it is preferable to use a neodymium magnet having a large coercive force.

  Here, the magnetic field generating unit 6 is not involved in rotationally driving the rotor Rm, but for suppressing the occurrence of arc sparks when the coil terminal 32 and a conductive contact described later are brought into contact with and separated from each other. A magnetic gap G that forms a DC magnetic field is formed between the magnetic pieces 62 and 62 constituting the magnetic field generating unit 6, and the tip of the coil terminal 32 enters the magnetic gap G. In particular, concave portions 62a are formed on the opposing surfaces of the magnetic pieces 62, 62, and the conductive contacts 7 are fitted and disposed in the concave portions 62a. The conductive contacts 7 are intermittently connected to the respective coil terminals 32. Thus, the conductive contact is sequentially made. That is, the coil terminal 32 and the conductive contact 7 rotate relative to each other about the rotor shaft 4 (in this example, the conductive contact 7 rotates together with the rotor shaft 4 while the coil terminal 32 is fixed), while the magnetic field Contact and separation in the DC magnetic field (magnetic gap G) by the generating unit 6.

  In this example, the conductive contacts 7 are a pair of positive and negative, and six (three sets) are incorporated at equal intervals in the circumferential direction as shown in FIG. In FIG. 2, the ones having different polarities are adjacent to each other. In FIG. 5, the hatched conductive contact 7 is a positive electrode, and the non-hatched white conductive contact 7 is a negative electrode.

  The conductive contacts 7 are conductively connected to a DC power source E (storage battery mounted in an automobile or the like) shown in FIG. 1 via a slide pin 71 penetrating the magnetic piece 62 and the rotor disk 5. However, the conductive contact 7 as the positive electrode is conductively connected to the positive electrode of the DC power source E via the slide pin 71, the rotating electrode plate 72a, and the fixed slider 72b, and the conductive contact 7 as the negative electrode is the slide pin. 71, the rotating electrode plate 73a, and the fixed slider 73b are conductively connected to the negative electrode of the DC power source E.

  The rotating electrode plates 72a and 73a are concentric with the rotor disk 5, respectively, and are fixed to the rotor disk 5 via electric insulators 72c and 73c. The rotating electrode plates 72a and 73a are fixed to the rotating electrode plates 72a and 73a. The fixed sliders 72b and 73b are in sliding contact with each other. The rotating electrode plates 72a and 73a and the sliders 72b and 73b are always in contact with each other without being separated from each other, and therefore no arc discharge occurs between them.

  Further, in FIG. 6, the conductive contacts 7 having the same polarity in the axial direction of the rotor shaft 4 face each other with the coil terminal 32 interposed therebetween, and are movable in the axial direction of the rotor shaft 4 in the recess 62a. ing. In particular, as is apparent from FIG. 7, a pressure spring 8 made of a compression coil spring or the like is incorporated in the magnetic piece 62 around the slide pin 71 whose one end is connected to the conductive contact 7. The conductive contact 7 is pressed against the conductive contact surface 32 a of the coil terminal 32 by the spring 8. For this reason, it is possible to supply a large drive current to the armature coil 2 by the contact between the conductive contact 7 and the coil terminal 32 while preventing the contact failure between the conductive contact 7 and the coil terminal 32. The conductive contact 7, the slide pin 71, and the pressure spring 8 are electrically insulated from the magnetic piece 62 and the rotor disk 5, respectively.

  Here, if the conductive contact 7 rotates while being pressed against the conductive contact surface 32a of the coil terminal 32 by a spring force, maintenance in a short period is required due to wear of both of them. Therefore, in the present example, the coil terminal 32 and the conductive contact 7 have a base material of copper or other good conductor, and a surface of which is super hard conductive film made of molybdenum, tungsten, or the like, which has better wear resistance than the base material. Is given. According to this, it becomes possible to make maintenance-free by suppressing wear of the coil terminal 32 and the conductive contact 7.

  In particular, according to the present invention, a semiconductive lubricant is interposed between the coil terminal 32 and the conductive contact 7, and the coil terminal 32 and the conductive contact 7 are in conductive contact via the semiconductive lubricant. It is like that. The semiconductive lubricant is a viscous fluid that exhibits electrical conductivity under pressure and exhibits electrical insulation under no pressure. In particular, the semiconductive lubricant is a liquid lubricant in which solid particles having conductivity are dispersed in a nonconductive lubricant having lubricity, or a semisolid lubricant. Fat type lubricating oil or hybrid lubricating oil is used, and carbon powder, copper or other metal powder is used as the conductive solid particles. And according to the semiconductive lubricant, a contact portion between the coil terminal 32 and the conductive contact 7 while imparting lubricity between the coil terminal 32 and the conductive contact 7 and suppressing wear of both. Only, the coil terminal 32 and the conductive contact 7 can be electrically connected. That is, when the conductive contact 7 is pressed against the conductive contact surface 32a of the coil terminal 32 by the pressurizing spring 8, the solid particles in the semiconductive lubricant interposed between the two are connected to each other and become conductive. It comes to show the sex. On the contrary, since the semiconductive lubricant exhibits electrical insulation in the non-contact portion between the coil terminal 32 and the conductive contact 7, the coil terminal 32 and the conductive contact 7 may be short-circuited by the semiconductive lubricant. Is prevented.

  In FIG. 7, the opposing conductive contacts 7 do not come into contact with each other due to the urging force of the pressure spring 8, and at least one coil terminal 32 is always interposed between the two contacts 7 and 7. By doing so, the coil terminal 32 is allowed to pass between the conductive contacts 7 and 7 facing each other.

  Next, the operation of the DC motor configured as described above will be described. The six conductive contacts 7 shown in FIG. 5 are arranged at intervals of five for the 36 coil terminals 32 shown in FIG. Conductive contact. As described above, since the positive and negative electrodes of the conductive contact 7 are alternately arranged in the circumferential direction, when a DC voltage is applied to the conductive contacts 7 from the DC power source E, a pair of positive and negative conductive contacts 7 is formed. In the armature coils 2 positioned between the coil terminals 32 that are in contact with each other, a drive current in a direction opposite to that of the adjacent armature coils 2 flows as a set of six. Thereby, the ring-shaped iron core 1 of the stator Sm having the armature coils 2 is magnetized so that N poles and S poles appear alternately every 60 degrees in the circumferential direction. This is schematically shown in FIG.

  In FIG. 8, when the positive electrode of the conductive contact 7 is indicated by a black circle and the negative electrode is indicated by a white circle, and one side of the iron core 1 is magnetized as shown in FIG. Are positioned so as to be out of phase by about 10 degrees with each pair of armature coils 2 facing the same magnetic poles. Therefore, in the state of FIG. 8, the rotor including the field magnet 51 rotates counterclockwise in FIG. 8, and as a result, when the conductive contact 7 is rotated by one coil terminal 32 (one pitch), the electric machine The magnetic pole of the iron core 1 by the child coil 2 moves in the rotation direction of the rotor by one armature coil 2, and by repeating this, the rotor continuously rotates in one direction.

  As described above, according to the DC motor, the armature coil 2 and the coil terminal 32, the field magnet 51, and the conductive contact 7 are arranged on the same axis. High rotational performance can be obtained without constructing a control circuit.

  Here, when intermittent conductive contact between the coil terminal 32 and the conductive contact 7 is repeatedly performed, an arc spark due to arc discharge is generated between the two, and according to the present invention, A DC magnetic field is formed between a pair of magnetic poles of the magnetic piece 62 facing each other across the contact portion between the terminal 32 and the conductive contact 7, and the coil terminal 32 and the conductive contact 7 are within the DC magnetic field (magnetic gap G). When the arc discharge I is generated between the coil terminal 32 and the conductive contact 7 as shown in FIG. 9 due to the contact separation, the direction orthogonal to the arc discharge I and the DC magnetic field B (rotation of the rotor) The Lorentz force F based on Fleming's left-hand rule is generated with respect to the radial direction), and the Lorentz force F acts to blow off the spark caused by the arc discharge I. For this reason, generation | occurrence | production of arc discharge and the arc spark resulting from this is suppressed, and the bad influence to other electronic devices by generation | occurrence | production of an electrical noise can be prevented by extension. In FIG. 9, L represents the semiconductive lubricant.

  The specific example of the present invention has been described above. However, the magnetic field generating unit 6 is not limited to an integral structure of the ring-shaped permanent magnet 61 and the magnetic piece 62, and a plurality of independent individual components with the rotor shaft 4 as the center. You may make it arrange | position on the same periphery. In the illustrated example, the magnetic field generating unit 6 is provided on the rotor Rm side, but it may be provided on the stator Sm side.

E DC power source Sm Stator Rm Rotor L Semiconductive lubricant 1 Iron core 2 Armature coil 3 Commutator 31 Insulating plate 32 Coil terminal 32a Conductive contact surface 4 Rotor shaft 5 Rotor disc 51 Field magnet (field system)
6 Magnetic field generation unit 61 Permanent magnet 62 Magnetic piece 7 Conductive contact 8 Pressure spring

Claims (4)

A plurality of armature coils through which a driving current for rotating the rotor shaft flows, a field system that generates a field flux acting on the armature coils, and coil terminals that are conductively connected to both ends of the armature coils; A magnetic field is formed between a pair of positive and negative conductive contacts that are conductively connected to a DC power source and intermittently conductively contact the coil terminal, and a pair of magnetic poles facing each other across the contact portion of the coil terminal and the conductive contact A DC motor comprising: a magnetic field generation unit configured to contact and separate the coil terminal and the conductive contact in a magnetic field generated by the magnetic field generation unit while relatively rotating about the rotor shaft. 2. The DC motor according to claim 1, further comprising a pressure spring that presses the conductive contact against the conductive contact surface of the coil terminal. 3. The coil terminal and the conductive contact are in conductive contact via a semiconductive lubricant that exhibits electrical conductivity under pressure and exhibits electrical insulation under no pressure. DC motor. 4. The DC motor according to claim 3, wherein the semiconductive lubricant is one in which solid particles having conductivity are dispersed in a lubricating oil having lubricity.

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