JP4014336B2 - 2-axis synchronous reversing drive motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a two-axis synchronous inversion drive motor, and more particularly to a drive motor for a rotating device that requires two axes to be simultaneously inverted and rotated, such as a two-axis gear pump, a roots blower, and a screw compressor.
[0002]
[Prior art]
Conventionally, a drive motor of a device that needs to reverse two axes at the same time is generally driven by one axis, and the two axes are driven synchronously and inverted by a gear.
However, Japanese Patent Laid-Open No. 4-178143 has proposed a drive motor that simultaneously inverts two axes. This type of motor has two rotors with permanent magnets arranged on the outer periphery so that the outer peripheral surfaces are in contact with each other or close to each other, and the different magnetic pole surfaces of each rotor are attracted to each other to form a magnetic coupling. Then, an armature is arranged on the outer periphery of each rotor with a predetermined gap, and the rotor is reversed and rotated by a space moving magnetic field of the armature. According to this type of drive motor, the two axes can be directly driven synchronously and inverted without using a gear. Further, since no gear is required, the two axes can be driven synchronously and reversely without having a mechanical connection between the two rotors.
[0003]
[Problems to be solved by the invention]
However, according to the motor of the above system, a rotating space moving magnetic field that generates a magnetic force based on the energization current is formed in the armature, and a magnetic coupling force acts between the rotors. The strength of the rotational drive magnetic field is not necessarily constant due to the non-uniformity of the windings and the non-uniformity of the magnetization of the permanent magnet provided around the rotor, and the uniform rotational force acting between the two rotors It is difficult to produce. For this reason, when two rotors are arranged in a non-contact manner, unbalanced loads are applied in the radial direction to the respective rotors and bearings that support the rotors. Therefore, in the motor disclosed in the above publication, a load force that is not necessarily uniform is applied, and it is not easy to synchronously reverse the two axes at high speed rotation stably.
[0004]
The present invention has been made in view of the problems of the related art, and an object thereof is to provide a two-axis synchronous inversion drive motor capable of stably synchronizing and reversing two rotors with a predetermined gap. .
[0005]
[Means for Solving the Problems]
2-axis synchronous inversion driving motor of the present invention, the permanent magnet parallel axially supported keeping the two rotors of Jo Tokoro gap was provided around the armature arranged with a predetermined gap to the outer periphery of each rotor In addition, in the armature non-arranged portion where the rotors are opposed to each other, the magnetic pole surfaces of the rotors are made to face each other to form a magnetic coupling, and each rotor is phase-inverted by the space moving magnetic field of the armatures the two-shaft synchronous inversion driving motor for rotating with respect to the line of symmetry perpendicular to the line connecting the center lines of the two axes, the arrangement of the armature for driving the right and left rotor is symmetrical, and the line of symmetry The armature windings at symmetrical positions are wound around the armature core so that they have the same phase and different magnetic poles, and the armature core is disposed on the inner periphery of the stator yoke. characterized in that the formation of the One of the motor.
[0006]
As an arrangement of armatures, armatures that are concentrated in salient poles that are in-phase and opposite in polarity are symmetrically arranged on the inner circumference of a common stator yoke and wired as a single motor. By doing so, it can be efficiently driven by the same drive device as one normal three-phase brushless DC motor. With the motor configuration of the present invention described above, the magnetic coupling force is strengthened by energization conversely without interfering with the magnetic field of the magnetic coupling formed by the rotors during energization, generating torque ripple, vibration, etc. Thus, the rotor can be smoothly rotated.
[0007]
The gap distance δ ₀ between the outer circumferences of the two rotors is preferably 1 to 3 times the gap distance δ ₁ between the outer circumference of the rotor and the inner circumference of the armature. Thereby, the arrangement of the armature and the rotor in which the magnetic coupling force and the space moving magnetic field are balanced can be achieved, and the efficiency can be increased. Further, since the predetermined gap distance is provided between the rotors, the load on the bearing can be reduced, and the torque ripple due to the deviation of the magnetized waveform between the rotors can be reduced.
[0008]
The inner peripheral surface of the armature is integrally molded with a nonmagnetic insulating material, and the gap distance δ ₂ between the outer circumferences of the rotors and the molding material is set to the gap distance δ ₀ between the outer circumferences of the two rotors. It is preferable that δ ₀ > 2δ ₂ and the two rotors face each other with the molding material interposed therebetween.
[0009]
The stator is molded integrally with resin, rubber, etc., and the rotor of the molding material is formed between the two rotors so that the rotors do not collide with each other. Can be prevented.
[0010]
In addition, in a non-armored portion where the rotors are formed to face each other, a through hole may be provided in the axial direction of each rotor to provide a fluid passage.
[0011]
Thereby, it is possible to effectively use two dead spaces that inevitably occur in the non-arranged portion of the armature where the rotors face each other. For example, by using it as a fluid passage for suction and discharge of a biaxial positive displacement pump, it is possible to obtain an extremely simple and inexpensive biaxial positive displacement pump motor with an electromechanical integrated structure by also combining cooling of the motor. it can.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0013]
FIG. 1 shows the structure of a two-axis synchronous inversion drive motor according to a first embodiment of the present invention. The two rotors are circumferentially arranged so that magnetic flux is generated in the radial direction at equal intervals symmetrically about the permanent magnet. That is, in this embodiment, the number of pole pairs of the permanent magnets of the two rotors is 3, and six poles of S, N, S, N, S, N are provided around each rotor.
[0014]
A stator core 1 having an armature having a structure symmetrical to a center line B between two rotor shaft centers and a symmetry line C perpendicular to the line B between the rotors is integrally fixedly disposed. In each stator core 1, an armature core 3 having a winding 4 is arranged apart from the circumferential surface of the rotor by a predetermined gap δ ₁ . The armature windings 4 are respectively U, V, W, U ′, V ′, W ′ (where U ′ is the reverse phase of U, V ′ is the reverse phase of V, and W ′ is U ₁ , U ₂ , which are windings of equal number of turns connected in series as shown in FIG. ₂ , and V _1, V ₂ , And two sets of windings W ₁ and W ₂ are arranged vertically symmetrically with respect to the center line B. The left and right armatures are symmetric with respect to the symmetry line C, and are in the same phase and in opposite phase. Here, as shown in FIG. 2, the winding 4 has U ₁ and U ₂ which are windings having the same number of turns connected in series, and U ₁ ′ and U ₂ ′ which are opposite phases thereof are connected in parallel. Connected to form the U phase. The same applies to the V phase and the W phase, and the U, V, and W phases are connected in a Y shape as a whole.
[0015]
In FIG. 1, two rotors are arranged with a predetermined inter-axis distance l, and each rotor surrounds a permanent magnet 5 magnetized with six poles at N and S alternately and at equal intervals on the outer periphery. Has been established. Of the six pole permanent magnets on the outer periphery of each rotor, two poles facing each other across the symmetry line C are used as magnetic couplings, and the remaining four poles are used as motors as drive magnetic poles as described above. It is the same. In this state, the outer circumferences of the rotors face each other while maintaining a predetermined gap distance δ ₀ , but the different magnetic pole surfaces are always attracted to each other to be stabilized and become magnetic coupling, and can be easily synchronously rotated only in opposite directions. .
[0016]
It is impractical to arrange the two rotors so that the permanent magnets of each rotor are in contact or in close proximity. Since machining of permanent magnets is not common, the dimensional accuracy around each rotor is generally not good. If contacted or brought close to each other in this state, the permanent magnets will cause partial friction, and the magnets are likely to be worn or cracked. . Even if a slight clearance is provided, the bearing is subjected to a load due to the strong suction force acting between the rotors, and the life of the bearing is shortened. Also, the magnetizing waveform of the rotor with two permanent magnets is not completely uniform in reality, and torque ripple occurs when the deviation of the magnetizing waveform between the two magnets is synchronously reversed as a magnetic coupling. This torque ripple also makes it easy to step out or vibrate when driven as a motor.
[0017]
Conversely, if the clearance between the two rotors is too large, the magnetic coupling force will decrease. Practically, when the gap distance between the inner circumference of the armature and the outer circumference of the rotor is δ ₁ , and the gap distance between the outer circumferences of the two rotors is δ ₀ , if δ ₀ ≈ (1-3) δ ₁ The attractive force between the two magnets and the attractive force between each rotor and the armature are substantially canceled, and the magnetic coupling force is sufficiently large and the torque ripple is small and practical.
[0018]
In the motor shown in FIG. 1, the two-pole rotor magnet used for the magnetic coupling is in contrast to the remaining four-pole rotor magnet, and each of the six-pole armatures has the same shape. A core is composed of a core 3 and armature windings 4 each having a salient pole concentrated winding), that is, a total of 12 armatures constitute one motor. The motor armature is arranged in such a manner that six poles are arranged symmetrically with respect to the symmetry line C orthogonal to each other at the position of 1/2 of the biaxial center line B, and symmetrical with respect to the left and right. The armature windings 4 in the same phase and the salient poles are wound around the armature core 3 in the opposite direction in the opposite direction, or they are energized in the opposite directions while the salient poles are concentrated in the same direction. The relationship. This makes it possible to drive as a single motor. Each armature is fitted and positioned in a common stator yoke 2. Thus, since this motor can be driven as one three-phase motor, naturally one drive power supply device (driver) is sufficient.
[0019]
The drive of the motor shown in FIG. 1 is performed in accordance with the rotor magnetic pole position as shown in the current flow (a1 to a6) of the windings and the rotation of the rotor (b1 to b6) in FIGS. By repeating the switching, each rotor can be reversed in the direction of the arrow by the space moving magnetic field generated by the armature, and the rotation can be continued. The energization method shown in FIGS. 3 to 8 (a1 to a6) is exactly the same as the energization method of a normal brushless DC motor. Similarly, a method of detecting the rotor magnetic pole position can use a Hall element or the like, or a method using the back electromotive voltage of each phase.
[0020]
In addition, by arranging the same phase in the same phase as the armature of this motor and in the opposite polarity, the U ₁ and U ₁ ′ and W ₂ and W ₂ ′ phases where the rotors face each other are energized. Therefore, the magnetic coupling force between the two rotors can be further strengthened by energization by energizing the magnetic poles together through the stator yoke 2 and attracting the different magnetic poles of each rotor simultaneously. Become.
[0021]
By the way, as described in the above prior art, if one motor, that is, “two complete motors” is formed for each rotor, for example, U ₁ → V in the rotation direction in FIG. Generally, it is considered that a winding is required to return to W ₂ → U _{1 in the order of 1} → W ₁ → U ₂ → V ₂ → W ₂ . However, in the armature layout of the motor of the present invention, since W ₂ · U ₁ always has a discontinuous shape, if there is a winding for returning to W ₂ → U ₁ , the rotors are opposed to each other by suction. Thus, the magnetic field performing the magnetic coupling action interferes with the magnetic field generated by the winding W ₂ → U ₁ , and torque ripple and vibration are generated. The present invention solves this magnetic field interference problem. That is, in the present invention, each armature winding is saliently concentrated on the armature, and there is no winding for returning to W ₂ → U ₁ , W ₂ ′ → U ₁ ′. Even if the W ₂ phase, U ₁ phase, and W ₂ 'phase and U ₁ ' phase are independent of each other, the adjacent U ₁ phase and U ₁ 'phase and W ₂ phase and W ₂ ' phase must be different due to current flow. Since it is a magnetic pole, the magnetic path is closed through the magnetic path of the stator magnet and the rotor magnet that is attracted and opposed, so that windings returning to W ₂ → U ₁ , W ₂ ′ → U ₁ ′ are unnecessary. In addition, the magnetic field in which the rotors are attracted to face each other and perform a magnetic coupling action is rather strengthened without being interfered by energization.
[0022]
In addition, the number of rotor magnetic poles, the number of armatures, and the combination shown in this embodiment can be considered in other ways, for example, the number of rotor magnetic poles is 4 and the number of armatures is 6. However, this embodiment is a preferable example in which the space is most effectively used and good efficiency is obtained in terms of the motor layout.
[0023]
FIG. 9 shows a two-axis synchronous inversion drive motor according to a second embodiment of the present invention. The motor shown in FIG. 9 employs a configuration in which the rotors do not directly collide with each other when the motor is assembled, which is a drawback of the prior art, and the permanent magnets are not damaged. That is, the stator integrated with the armature and the stator yoke is molded integrally with resin or rubber, etc., and at that time, the stator has the same diameter as the inner periphery of the armature or larger than the outer diameter of the rotor and smaller than the inner diameter of the armature. By making δ ₀ > 2δ ₂ with respect to the inner diameter δ _{2 of the} mold material so as to make the inner peripheral surface of the mold material, the barrier portion 7a of the mold material 7 can be formed between the two rotors. . Even if the rotors try to collide with each other at the time of assembly, the barrier part 7a can prevent the permanent magnet 5 from directly colliding and being damaged by being sandwiched between the barrier parts 7a of the molding material. Note Since the central portion of the barrier portion 7a becomes very thin by the size of the [delta] _0, the effect is not much even shape obtained by the missing part in advance.
[0024]
Also, when magnetized rotor magnets are inserted into an armature stator and assembled, the magnet attracting force is strong and (a) the rotors or (b) the rotor and the armature easily collide with each other. In addition, there is a problem that the magnet is easily damaged or damaged. In the motor of the present invention, this problem is solved by applying a mold made of a material such as resin or rubber to the entire armature so that it has the same diameter as the inner circumference of the armature or a smaller diameter than the inner circumference of the armature. Yes. That is, the clearance δ ₂ between the outer periphery of the rotor and the inner periphery of the mold material is δ ₀ > 2δ _2.
Then, even if there is a molding material barrier between the two rotors or a shape in which the central portion of the barrier is partially missing, it is possible to prevent the rotors from directly colliding with each other during assembly.
[0025]
Further, FIG. 9 shows through holes 8a and 8b provided in a dead space generated in an armature non-arranged portion formed by mutually opposing rotors. That is, the through holes 8 a and 8 b are provided in the armature-free portion of the molding material 7. The above-mentioned dead space is a characteristic part that inevitably arises from the motor configuration of the present invention at two places above and below the non-arranged portion of the armature formed with the rotors facing each other and sandwiching the rotor facing portion.
[0026]
On the other hand, a pump driven by a two-axis synchronous inversion drive motor requires a suction port and a discharge port for the fluid to be handled, where a hole penetrating the motor in the axial direction is provided as a fluid passage, and a roots pump, It is also convenient in terms of position to use as a suction port and a discharge port of a gear pump or the like. Further, the passage of fluid through the hole passing through the motor also helps cool the motor, and there is an advantage that it is not necessary to provide a special cooling device for the motor. Furthermore, if this through-hole is disposed in the above-mentioned mold material, the heat generated by the armature winding is transmitted to the mold material 7 and discharged well, and the cooling effect is further improved.
[0027]
10 and 11 show a Roots pump employing the motor of the present invention. By the way, most of the uses of the biaxial synchronous reversing drive motor of the present invention are positive displacement pumps that require biaxial reversal. Above all, root pumps, gear pumps, etc. require a suction port and a discharge port above and below the central part where the two pump rotors 9 are engaged. Therefore, the two dead spaces in the motor are defined as the suction port of this pump. It is preferable to use the fluid passages 8a and 8b passing through the discharge ports. The illustrated Roots pump includes a rotor 6 having permanent magnets 5 around two main shafts 6, and is driven to rotate by an armature core 3 having a winding 4 disposed on a stator yoke 2. An axis synchronous reversing drive motor is provided. In this motor, the inner periphery of the armature and the non-armature-arranged portion are filled with the molding material 7. The main shaft 6 is supported by a bearing 11 and is provided with a roots-type rotor 9 on the right side in the drawing to perform liquid feeding. Two through holes 8a and 8b penetrating in the axial direction are provided inside the motor, and are opened as a suction port 8a and a discharge port 8b in a pump chamber provided with a roots-type rotor 9. Accordingly, when the armature winding 4 is energized, the rotor (main shaft) 6 is rotated, the roots-type rotor 9 is rotated, and liquid feeding is performed by the pump through the through holes 8a and 8b.
[0028]
In this motor, the armatures 3 and 4 generate heat when energized, but the motor can be cooled by the fluid flowing through the through holes 8a and 8b.
[0029]
Although FIG. 9 shows an example in which a through hole is directly provided in the above-described molding material 7a, a pipe or the like may be arranged in the space without filling the molding material.
[0030]
In the above-described embodiment, only preferred examples have been shown, and it goes without saying that various modified examples are possible without departing from the spirit of the present invention. Of course, the through-hole provided in the motor may be used as a refrigerant passage for simply cooling the motor, not as a pump suction / discharge passage. Further, in this embodiment, an example of a roots type pump having a very simple structure using this motor as a fluid suction channel and a discharge channel has been shown, but the present invention is not limited to this application. .
[0031]
【The invention's effect】
Generally, according to the present invention, it is possible to provide a two-axis synchronous inversion drive motor that is highly stable and practical.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a structure of a two-axis synchronous inversion drive motor according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a wiring connection of the motor.
3A is a diagram illustrating a current flow of the connection in FIG. 2, and FIG. 3B is a diagram illustrating a current flow of the armature winding and rotation of the rotor of the motor of FIG. 1;
4A is a diagram showing the current flow of the connection in FIG. 2, and FIG. 4B is a diagram showing the current flow of the armature winding and the rotation of the rotor of the motor of FIG. 1;
5A is a diagram showing the current flow of the connection in FIG. 2, and FIG. 5B is a diagram showing the current flow in the armature winding and the rotation of the rotor of the motor in FIG. 1;
6A is a diagram showing the current flow of the connection in FIG. 2, and FIG. 6B is a diagram showing the current flow in the armature winding and the rotation of the rotor of the motor in FIG. 1;
7A is a diagram showing the current flow of the connection in FIG. 2, and FIG. 7B is a diagram showing the current flow in the armature winding and the rotation of the rotor of the motor in FIG. 1;
8A is a diagram showing the current flow of the connection in FIG. 2, and FIG. 8B is a diagram showing the current flow in the armature winding and the rotation of the rotor of the motor in FIG. 1;
FIG. 9 is a sectional view showing a structure of a two-axis synchronous inversion drive motor according to a second embodiment of the present invention.
10 is a longitudinal sectional view of a Roots pump including the motor shown in FIG.
11 is a view showing a cross section AA in FIG. 10;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Motor frame 2 Stator yoke 3 Armature core 4 Armature winding 5 Permanent magnet (rotor magnet)
6 Rotor 7 Mold material 7a Mold material barrier 8a Through hole (for suction)
8b Through hole (for discharge)
9 Roots-type rotor 11 Bearing B Center line C Symmetric line 1 Biaxial distance δ ₀ Gap distance between the outer circumferences of the two rotors δ ₁ Gap distance between the outer circumference of the rotor and the inner circumference of the armature δ ₂ Between the outer circumference of the rotor and the inner circumference of the mold material Air gap distance

Claims (7)

The permanent magnet parallel axially supported keeping the two constant gap Tokoro rotor was provided around the place armature with a predetermined air gap on the outer periphery of each rotor, it is formed by and opposed rotors have phase In a two-axis synchronous reversal drive motor in which different magnetic pole surfaces of the rotors are opposed to each other in a non-arranged portion of the armature to constitute a magnetic coupling and each rotor is rotated in a phase-reversed manner by a space moving magnetic field of the armature ,
Symmetry line perpendicular to the line connecting the center lines of the two axes, the arrangement of the armature for driving the right and left rotor is symmetrical, and an armature winding in a symmetrical position with respect to the symmetry line 2 axes are salient pole concentrated winding in the armature iron core so as to and different magnetic poles in phase armature iron core, characterized in that the formation of the one motor is arranged on the inner periphery of the stator yoke Synchronous reverse drive motor. 2. The two-axis synchronous inversion drive according to claim 1, wherein a gap distance [delta] ₀ between the outer circumferences of the two rotors is ₁ to 3 times the gap distance [delta] ₁ between the outer circumference of the rotor and the inner circumference of the armature. motor. The inner peripheral surface of the armature is integrally molded with an insulating material of a non-magnetic, the gap distance [delta] ₂ between the rotor outer periphery and the mold material, [delta] with respect to the two rotors the outer periphery of the gap distance [delta] _{0 0} > have a relationship of 2.delta. _2, 2-axis synchronous inversion driving motor according to claim 1, wherein the two rotors, characterized in that the facing sides of the molding material.   4. The fluid passage according to claim 1, wherein a through hole is provided in the axial direction of each rotor in a non-arranged portion of the armature formed so that the rotors face each other. 5. Axis synchronous reversing drive motor. 2. The two-axis synchronous inversion drive motor according to claim 1, wherein the armature winding for driving the two rotors is connected to one drive device. 2. The two-axis synchronous inversion drive motor according to claim 1, wherein the current supplied to the armature winding has three phases, and two phases of the current are sequentially supplied to the armature winding. 2. The two-axis synchronous inversion drive according to claim 1, wherein the number of pole pairs of the permanent magnets of the two rotors is 3 and the number of the armatures arranged around the two rotors is 6, respectively. motor.

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