JP4420172B2 - Bearingless rotating machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bearingless rotating machine, and more particularly to a bearingless rotating machine that generates electromagnetic force by disconnecting windings and increasing the number of phases in an electric machine wound with a short-pitch winding.
[0002]
[Prior art]
In addition to the same winding for the same rotating machine as the conventional winding, another set of windings different from the number of windings are wound around the stator core of the bearingless rotating machine, and the stator rotates with the current flowing through this winding. The magnetic flux distribution in the space between the rotors was distorted, and a radial force was generated in the rotor by the distortion of the magnetic flux distribution to magnetically support the rotor.
In addition, in the bearingless rotating machine using an air bearing especially used in dental practice, the rotor is held in the radial direction by sending compressed air to the gap between the rotor sleeve and the bearing sleeve so as to float and hold it in a non-contact manner. Was.
[0003]
[Problems to be solved by the invention]
However, it wound around the winding and radial forces winding torque in distributed winding in the former means, leading to reduction or increase of the coil end of the output density with decreasing the space factor, the downsizing is There was a problem.
Use therefore, and the torque current in one of windings without wound radial force windings, to generate a current for radial force, and the short-pitch winding for an increase in space factor or the output density Provide a winding method.
Further, the supply of compressed air and the structure of the rotor sleeve and the bearing sleeve for holding the rotor of the latter means in a non-contact manner with compressed air are complicated and require precise machining. Since there is no compressed air when the rotating machine is stopped, the stator and the rotor are in contact with each other, and if there is a malfunction in the air control circuit at the start, there is a risk of rotating while contacting.
The present invention provides a new bearingless rotating machine that solves these problems.
[0004]
[Means for solving problems]
In view of the above, the present inventors have solved this problem by the following means as a result of intensive experimental research.
(1) A plurality of salient pole-shaped stator cores are formed, and short-turn windings are wound around the stator cores, and the windings are connected independently or with other windings. One end of each winding is connected to the converter and the other end is connected to the neutral point or the return side of the converter, and the converter is connected to the winding of the opposite stator core. A bearingless rotating machine configured such that torque and radial force can be generated simultaneously with a single type of winding with unbalanced current and voltage .
(2) A rotor core is arranged on the main shaft, a plurality of permanent magnets are arranged on the rotor core, and a plurality of stator cores are arranged opposite to each other via a gap on the outside of the rotor. The bearingless rotating machine according to item (1), characterized in that
[0005]
(3) An electromechanical instrument comprising the bearingless rotating machine described in (1) or (2) above.
(4) A dental instrument provided with the bearingless rotating machine according to (1) or (2).
(5) A machine tool comprising the bearingless rotating machine according to (1) or (2).
(6) An information processing machine comprising the bearingless rotating machine according to (1) or (2).
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
FIG. 15 is a cross-sectional view of a storage portion showing the configuration of a torque winding and a radial force winding of a conventional bearingless rotating machine.
In the figure, 1a is an N-pole permanent magnet buried in the rotor, 1b is an S-pole permanent magnet buried in the rotor, 2 is a stator, 3 is a salient-pole stator core, and 4 is a rotor. 5 is the main shaft, 6 is the rotational direction, 7 is the motor torque winding, 8 is the radial force, 20 is the bipolar radial force winding, NU is the U phase motor rotating torque winding, NV Is a V-phase motor rotation torque winding, NW is a W-phase motor rotation torque winding, NUb is a U-phase radial force winding, NVb is a V-phase radial force winding, and NWb is W-phase radial force windings, S1 to S12 are slot numbers, ○ is marked with a dot, the direction of the line from the far side to the near side, ○ is marked with a cross, the forward side is from the near side Indicates the direction of the line.
In each of the slots S1 to S12, the large outer circle indicates the wiring of the torque winding, and the small inner circle indicates the wiring of the radial force winding .
Further, the arrow to the inside of each winding indicates the direction of the input current, and the arrow to the outside indicates the direction of the output current. The winding method of this instrument is distributed winding.
The winding terminals of the motor rotation torque windings NU, NV, NW and the radial force windings NUb, NVb, NWb are connected to converters (for example, FIG. 4 or FIG. 5). One end is connected to the output end of the converter and the other end is connected to the neutral point of the winding or the return side of the converter (not shown).
[0007]
And, since each winding of the torque windings NU, NV, NW is three-phase four-pole in the case of FIG. 15, for example, the V-phase NV winding is, from the direction of the arrow input current inward, As shown in the drawing, from the large circle outside the slot 8 to the circle, the slot S11 is circled to the circle and the circle between S8 and S11, and the terminal is wound to the circle in the slot S8. The circle next to the mark is connected to the mark x,
Next, the slot S5 is circled to the circle and marked with a circle between S8 and S5, and the terminal is looped to the adjacent circle with a circle to the circle between S5 and S2. The terminal is wound a predetermined number of times, and the terminal passes through the adjacent S2 circles with a cross, and is wound a predetermined number of times between S2 and S11.
The last winding terminal after winding of the four poles is output as a torque winding NV in the output current direction of the arrow from the circle to the outside of the slot 11.
As described above, the input / output terminals of the winding are connected to an NV drive supply source (not shown).
[0008]
Similarly, the W-phase NW winding is wound between each of the slots S6 to S9, S6 to S3, S3 to S12 and S12 to S9, and the input / output terminal is connected to an NW drive supply source (not shown). The
Similarly, the U-phase NU winding is wound between each of the slots S10 to S1, S10 to S7, S7 to S4, and S4 to S1, and the input / output terminal is connected to a NU drive supply source (not shown).
Thus, the three-phase four-pole torque winding ends.
[0009]
Next, windings NUb, NVb, and NWb for obtaining a radial force are performed.
In the case of FIG. 15, since there are three phases and two poles, the NVb winding of the NV phase, for example, from the direction of the arrow input current to the inside, the small circle inside the slot S2 as shown in FIG. A small circle is connected to the mark, and the space between S2 and S9 is wound. Then, the terminal is connected to a small circle in the slot S9 from a mark to a small circle in S3, and the terminal is connected to S8. The small circle of ○ is connected to the mark, and between S3 and S8 is wound,
Finally, the winding NVb for obtaining the radial force in the output current direction indicated by the outward arrow from the slot S8 is provided.
The input / output terminal for the winding is connected to an NVb drive supply source (not shown).
[0010]
Similarly, the W-phase NW winding is input from the slot S6, wound between S6 to S1, and S7 to S12, and output from S12.
The input / output terminal is connected to an NW drive supply source (not shown).
Similarly, the NU winding of the U phase is
The slots S10 to S5 and S11 to S4 are wound around, and the input / output terminals are connected to a NUb drive supply source (not shown).
This completes the winding work for the radial force winding .
As shown, in addition to the stator torque winding 7 (four-pole winding) of the stator, another set of radial force windings 20 (two poles) different from the above-mentioned number of poles are wound. The current flowing in this winding distorts the magnetic flux distribution in the gap between the stator 2 and the rotor 4, and generates a radial force in the rotor due to the distortion of the magnetic flux distribution to hold the rotor magnetically. ing.
Further, the terminal of the motor rotating torque winding 7 and each winding terminal of the radial force winding 20 are connected to the converter of the drive supply source, one end to the output end of the converter and the other end. Is connected to the neutral point of the winding or to the return side of the transducer (not shown).
[0011]
FIG. 1 is a cross-sectional view of a storage portion showing the structure of a torque and radial force winding method (U phase) of a small bearingless rotating machine of the present invention.
In the figure, U1 is a torque winding, U2 is a radial force winding, an inward arrow indicates an input current direction, and an outward arrow indicates an output current direction. Note that the line symbol ○ is the same as the symbol X and the symbol ○ is the same as described above.
Further, each winding terminal of the motor rotating torque winding U1 and the radial force winding U2 is connected to a converter (FIG. 4 or FIG. 5 described later) of a drive supply source, and one end is an output of the converter. To the end, the other end is connected to the neutral point of the windings or to the return side of the transducer (not shown).
As a winding method that generates torque current and position control current with the one type of winding and uses short-pitch winding to increase the space factor or power density,
As shown in the figure, the U-phase winding of the torque winding is divided into two parts U1 and U2 as shown in the drawing for rotation U1 and the radial force winding U2, and is passed in the direction shown in the figure. To line.
In the figure, the winding direction is U2 opposite to U1.
[0012]
First, when rotating as an electric motor, torque is generated by flowing current in the same direction through the U-phase torque winding U1 and the winding U2 for obtaining radial force, and the rotation direction 6 Rotate clockwise.
In order to generate a radial force, a current is passed in the opposite direction to U2 with respect to U1.
As shown in the figure, when U1 and U2 are energized, the upper and left magnet parts (N pole permanent magnet 1a and S pole permanent magnet 1b) strengthen the magnetic field, and the lower and right magnet parts (N pole permanent magnets). The magnet 1a and the S-pole permanent magnet 1b) are weakened. Therefore, the radial force 8 of the arrow can be generated at the upper left.
[0013]
Similarly, the winding method for obtaining the torque winding and the radial force by the V-phase winding and the W-phase winding will be described.
FIG. 2 shows a V-phase winding method for obtaining torque and radial force,
FIG. 3 shows a W-phase winding method for obtaining torque and radial force.
In the figure, V1 is a torque winding, V2 is a radial force winding, W1 is a torque winding, and W2 is a radial force winding.
Similarly to the U-phase winding, the V-phase winding and the W-phase winding are divided into V1 and V2 and W1 and W2, respectively, and a current is passed in the direction of the drawing to thereby rotate each in the rotational direction 6. And a radial force 8 can be generated.
[0014]
In the above method, when current is supplied by an inverter, as shown in FIG. 4, in order to separate U1 and U2 and supply separate currents in one winding , one single-phase inverter is used. Four switching elements are required.
Therefore, 24 switching elements are required to supply current to all six windings .
FIG. 4 is a configuration diagram of only U1 as an inverter when a current is separately supplied to each phase. In the figure, 21 is a single-phase inverter, 16 is a switching element, 17 is a diode, and 18 is a DC power source.
An inverter for U2 ( radial force winding) (not shown) has a similar configuration.
[0015]
However, as shown in the following figure (FIG. 5), a neutral point is provided between the two windings of each phase and connected, so that control with half of the switching elements becomes possible.
FIG. 5 is a configuration diagram of the inverter when the neutral point is taken.
In the figure, 15 is a neutral point, 22 is an inverter, U1p is a U-phase torque drive circuit, U2p is a U-phase radial force drive circuit, V1p is a V-phase torque drive circuit, and V2p is V Phase radial force drive circuit, W1p is a W phase torque drive circuit, and W2p is a W phase radial force drive circuit.
As shown in the figure, there is a neutral point 15 between the U1 and U2 windings, and each phase is connected separately by the V1 and V2 windings and the W1 and W2 windings. The total of four switching elements 16 can be controlled by a total of four U-phases, V-phases, and W-phases.
[0016]
The converter (inverter) supplies voltage and current to the winding, generates an electromagnetic force by imbalanced the current and voltage, and generates torque.
The control circuit of the output transistor (FIG. 5), which is the switching element 16, has a high-frequency sine wave voltage or high-frequency voltage generation circuit using PWM, and detects the rotation angle position of the rotor and the detected rotation. Has a function of driving the inverter circuit based on the angle (not shown)
Moreover, the main circuit of converters, such as a bearingless rotating machine drive inverter or a converter for bearingless generators, can be set to four phases or six phases.
[0017]
Then performed in a rotary machine having a winding of the short-pitch winding, each salient pole of the stator core 3 wound on the winding divided into several groups, parallel to each group, or a series connection, Torque and radial force can be generated simultaneously.
With the configuration described above, the structure is simple, robust, small and light, and the shaft output can be improved.
[0018]
Figure 6 is a three-phase winding, a diagram of a four-pole rotor. The number of salient pole-shaped stator cores 3 is six, and one phase is composed of two stator cores and a three-phase winding is wound.
In the figure, n represents a neutral point.
The salient pole of the stator core 3, the short-pitch winding winding is wound, the torque for winding is configuration U1 and radial forces winding U2, voltage, current is supplied (Fig. Not shown). One end of the winding is connected to the neutral point n.
In addition, V1, V2 and W1, W2 windings are wound around each salient pole-shaped stator core 3.
The number of poles of the rotor 4 may be a natural number such as 2, 3, 4, 5, 6, 7, etc. in addition to the four poles.
Furthermore, the number of salient pole stator cores 3 may be a natural number such as 1, 2, 3, 4, 5, 6, 7,. The example is shown in FIG.
In the figure, the rotor 4 has a cylindrical rotor embedded with two permanent magnets 1a and 1b, a total of four permanent magnets, and these permanent magnets have NSNS on the outside so as to form four poles. Magnetized.
And although the shape of the said permanent magnet has drawn the bread loaf type | mold, as shown later, any of various types, such as an IPM type | mold, a SPM type | mold, a spoke type | mold, an inset type | mold, may be sufficient. For example, any of the formats described in Technical Report No. 719 (1999) of the Institute of Electrical Engineers, Yoji Takeda et al. “Design and Control of Embedded Synchronous Motor, 2001 Ohmsha”, etc. can be applied.
[0019]
Figure 7 is a four-phase winding, in view of the four-pole rotor,
The number of salient pole-shaped stator cores 3 is four, and one stator core constitutes one phase and a diagram in which four-phase windings are applied is shown.
In the figure, a is an a-phase winding, b is a b-phase winding, c is a c-phase winding, d is a d-phase winding, and 19 is a neutral point n or an output (connection) to an inverter.
Each phase winding constitutes a, b, c, and d phases, one end of the winding is connected to the output end of each phase of the drive converter (inverter), and the other end is independently connected to the converter. May be connected to the n point as a neutral point.
In either case, the current of each phase is controlled independently, and when the neutral point n is connected, the constraint condition that the sum of the currents of each phase is 0 is applied.
Moreover, although the case where the rotor 4 is 4 poles is drawn, the pole number of the rotor 4 should just be a natural number.
The figure shows the case where one winding constitutes one phase. If the number of the stator 2 is eight salient-pole stator cores 3, it is connected in series or in parallel. And one phase may be constituted by two windings .
The rotor 4 has four bread loaf magnets embedded therein.
The various rotor configurations can be applied.
[0020]
Figure 8 is a three-phase winding, in view of the four-pole rotor,
In the figure, U is a U-phase winding, V is a V-phase winding, and W is a W-phase winding.
The number of salient pole-shaped stator cores 3 is three, and a configuration diagram in which a three-phase winding is applied is shown.
A short-pitch winding is wound around the salient pole-shaped stator core 3.
The three currents are respectively controlled to generate the radial force 8 and the torque direction force 6. The salient pole tip of the stator core 3 has a radius slot, but may be a closed slot or an open slot. Any type of slot shape can be applied to all the embodiments.
[0021]
Figure 9 is a five-phase winding, a diagram of the four-pole rotor.
In the figure, e indicates an e-phase winding.
The number of salient pole of the stator core 3 is five, each short-pitch winding of the windings of a~e is wound, it constitutes a 5-phase winding.
As apparent from FIGS. 6 to 9 described above, the number of poles of the stator 2 may be a natural number of 3 or more.
When the number of poles of the stator 2 is large, it is possible to reduce the number of phases by connecting two windings in series as shown in FIG.
Although there are 12 windings in FIGS. 1 to 3, a 6-phase winding is configured by connecting them in series. It is also possible to form a four-phase winding by connecting three windings in series.
On the other hand, an arbitrary natural number can be selected as the number of poles of the rotor 4.
[0022]
Figure 10 is a 5-phase winding, a diagram of the 8-pole rotor (rotor).
FIGS. 11 to 13 show variations of the rotor,
FIG. 11 is a configuration diagram of a spoke type, 6 salient pole stator core 4 pole spoke rotor,
FIG. 12 is a configuration diagram of an IPM type, 6 salient pole stator core 4 pole IPM rotor,
FIG. 13 is a block diagram of an inset type, 6 salient pole stator core 4 pole inset rotor.
11 to 13 show the case where the stator 2 has six salient-pole stator cores 3, but as shown in FIG. 14 and the like, 3, 4, 5, 6, 7, 8 , 9, 10, 11, 12, etc.
FIG. 14 shows a configuration diagram of a 12 salient pole stator core 4 pole inset rotor.
[0023]
The bearingless rotating machine described above can be used for various electric machines.
When the bearingless rotating machine is used for a dental spindle,
In a conventional bearingless rotating machine that uses an air bearing, the rotor is held in a radial direction by sending compressed air to the gap between the rotor sleeve and the bearing sleeve to lift it in a non-contact manner. Although processing was required, as described above, the structure is simple and robust, the size and weight are reduced, and the shaft output can be improved.
In addition, when used for a spindle of a machine tool or an information processing machine, the structure is similarly simple and robust, the size and weight are reduced, and the shaft output can be improved.
[0024]
【The invention's effect】
According to the present invention, the following excellent effects are exhibited.
1. According to the invention of claim 1 of the present invention,
A plurality of salient pole-shaped stator cores are formed, and short-winding windings are wound around the stator cores, and each winding is independent or connected to other windings to form a plurality of phases. And one end of each winding is connected to the converter and the other end is connected to the neutral point or the return side of the converter, and the converter is connected to the current and voltage of the windings of the opposite stator core. Is configured so that torque and radial force can be generated at the same time.
It is possible to generate torque current and radial force current with one kind of winding without winding the radial force winding, increase the space factor or output density, and the structure is simple and robust It is small and light, and the shaft output can be improved.
2. According to the invention of claim 2 ,
A rotor core is disposed on the main shaft, a permanent magnet is disposed on the rotor core, and a plurality of stator cores are disposed opposite to each other via a gap on the outside of the rotor. It is simple and robust, small and light, and can improve shaft output.
[0025]
4. According to the invention of claim 4,
By setting the number of phases to 4 to 6, it can be selected according to the application, and the structure can be simplified.
5. According to the inventions of claims 5-6,
The converter supplies voltage and current to the windings, generates an electromagnetic force by unbalanced the current and voltage, and generates torque. For a bearingless rotating machine drive inverter or a bearingless generator By setting the main circuit of the converter such as the converter of 4 to 4 or 6 phases, it is possible to match the number of phases of 4 or 6 described above.
6. According to the invention of claim 7, the coils wound around each salient-pole stator core are divided into several groups, and the torque and radial force can be generated simultaneously by performing parallel or series connection for each group. Therefore, torque and position control current can be generated with one type of winding without winding the position control winding, and the space factor or output density can be increased. The structure is simple, robust and compact. It is lightweight and can improve the shaft output.
[0026]
3. According to the invention of claim 3 ,
The bearingless rotating machine can be applied to various electromechanical devices and has a wide range of use.
4. According to the invention of claim 4 ,
By using it in a dental machine, the holding of the rotor in a conventional bearingless rotating machine using air bearings is complicated and requires precision machining. However, this rotating machine is simple, robust, compact and lightweight. In addition, the shaft output can be improved.
5. According to the invention of claim 5 ,
When used for a spindle of a machine tool, the structure is simple and robust, small and light, and the shaft output can be improved.
6. According to the invention of claim 6 ,
By using it for a spindle of an information processing machine, the structure is simple and robust, the size and weight are reduced, and the shaft output can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a storage portion showing a configuration of a winding method of a torque and radial force winding of a small bearingless rotating machine according to the present invention.
FIG. 2 shows a V-phase winding method for obtaining torque and radial force.
FIG. 3 shows a W-phase winding method for obtaining torque and radial force.
FIG. 4 is a configuration diagram of only U1 in an inverter when a current is separately supplied to each phase.
FIG. 5 is a configuration diagram of an inverter when a neutral point is taken.
[6] 3-phase windings, a diagram of four-pole rotor.
[7] 4-phase winding, a diagram of four-pole rotor.
[8] 3-phase windings, a diagram of four-pole rotor.
[9] 5-phase winding, a diagram of four-pole rotor.
[10] 5-phase windings, the 8-pole rotor FIG.
FIG. 11 is a configuration diagram of a spoke type, 6 salient pole stator core 4 pole spoke rotor.
FIG. 12 is a configuration diagram of an IPM type, 6 salient pole stator core 4 pole IPM rotor.
FIG. 13 is a configuration diagram of an inset type, six salient pole stator core four pole inset rotor.
FIG. 14 is a configuration diagram of a 12 salient pole stator core 4 pole inset rotor.
FIG. 15 is a cross-sectional view of a storage portion showing the configuration of a torque winding of a conventional bearingless rotating machine.
[Explanation of symbols]
1a: N-pole permanent magnet buried in the rotor 1b: S-pole permanent magnet buried in the rotor 2: Stator 3: Salient-pole stator core 4: Rotor 5: Main shaft 6: Direction of rotation 7 : Motor torque winding 8: Radial force 15: Neutral point 16: Switching element 17: Diode 18: DC power supply 19: Neutral point n or connection to inverter 20: Bipolar radial force winding 21 : Single-phase inverter 22: Inverter NU: Torque winding for motor rotation of U phase NV: Winding for torque of motor rotation of V phase NW: Winding for torque of motor rotation of W phase NUb: Radial direction of U phase power winding NVb: V-phase of the radial force winding NWb: W radial force winding of phase S1 to S12: slot number of a: a-phase winding phase portion b: b-phase winding phase portion c: c-phase winding Wire d: d phase winding e: e phase winding U: U phase winding V: V phase winding W: W-phase winding U1: torque windings U2: radial force winding V1: torque winding V2: radial force winding W1: torque winding W2: radial force winding U1p: U-phase torque drive circuit U2p: U-phase radial force drive circuit V1p: V-phase torque drive circuit V2p: V-phase radial force drive circuit W1p: W-phase torque drive circuit W2p: W Phase radial force drive circuit

Claims (6)

A plurality of salient pole-shaped stator cores are configured, and a short-pitch winding is wound around the stator cores,
Each winding is independent or connected to other windings to form multiple phases, and one end of each winding is connected to the converter and the other end is connected to the neutral point or the return side of the converter And
The converter unbalances the current and voltage of the opposing stator core windings,
One bearingless rotary machine which is characterized by being configured to allow generating a torque and radial forces simultaneously winding. A rotor core is arranged on the main shaft, a plurality of permanent magnets are arranged on the rotor core, and a plurality of stator cores are arranged opposite to each other via a gap on the outside of the rotor.
The bearingless rotating machine according to claim 1 , wherein An electromechanical instrument comprising the bearingless rotating machine according to claim 1. A dental instrument comprising the bearingless rotating machine according to claim 1 or 2. A machine tool comprising the bearingless rotating machine according to claim 1. An information processing machine comprising the bearingless rotating machine according to claim 1.

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