Variable back electromotive force motor

Abstract

To provide a variable back electromotive force motor with a configuration that allows the back electromotive force to be varied without requiring to change a winding or wiring method, or to demagnetize and re-magnetize a magnet.SOLUTION: A variable back electromotive force motor 10 has a variable back electromotive force configuration in a motor composing a shaft (back yoke) 9, a rotor 6 mounted on the shaft 9, and a stator 8, in which the rotor 6 includes a magnet 7, and the shaft 9 includes a cylindrical movable back yoke 2 made of a magnetic material that can be adjusted in the axial direction as a member for changing the back electromotive force.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a counter electromotive voltage variable motor, and more particularly to a counter electromotive voltage variable motor having a variable counter electromotive voltage configuration without changing the winding or connection method, or requiring demagnetization and remagnetization of the magnet.

Background Art

[0002] Conventionally, in motors having the same physical size (specifications such as flange size) and structure, when changing the counter electromotive voltage, there is a method of changing the winding specification. Alternatively, it can be made variable by changing the number of coil circuits externally. Further, Patent Document 1 cited below discloses a method using demagnetization and remagnetization of a magnet as a variable magnetic flux motor drive system for easily suppressing the counter electromotive voltage and preventing the generation of braking force in the high-speed range.

[0003] This is a variable magnetic flux drive system including a variable magnetic flux motor having a variable magnet which is a permanent magnet with low holding force, a first inverter for driving the variable magnetic flux motor, a second inverter having a function of supplying a magnetization current for controlling the magnetic flux of the variable magnet, a stop demagnetization determination unit for determining whether or not to demagnetize the variable magnet and generating a demagnetization signal based on the result, and a third inverter having a function of demagnetizing the variable magnet based on the demagnetization signal generated by the stop demagnetization determination unit.

[0004] Further, Patent Document 2 cited below discloses a structure in which a pair of reactors are arranged opposite to both end faces of a stator core as a method capable of controlling the torque characteristics and output characteristics of a motor with a simple structure, and the magnetic flux generated in one reactor core is passed through the stator core to the other reactor core by the current flowing through the reactor coil. With such a configuration, it is said that the counter electromotive force generated as the permanent magnet rotates can be controlled by controlling the reactor current.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, as a method for changing the back electromotive force in a motor having the same physique and structure, in the above-described method of changing the winding specification, only one characteristic can be obtained per unit, and there is no freedom in changing the back electromotive force. On the other hand, in the method of changing the number of coil circuits externally, a circuit number switching device is required separately, resulting in an increase in cost, which is not preferable. The method of performing demagnetization and remagnetization of magnets is also complicated.

[0007] Therefore, the problem to be solved by the present invention is to eliminate the problems of such prior art and provide a back electromotive force variable motor with variable back electromotive force without changing the winding or connection method or requiring demagnetization and remagnetization of magnets.

Means for Solving the Problems

[0008] The inventor of the present application studied the above problems. As a result, the following was conceived. That is, a magnetic material is used in the magnet portion of the rotor to provide a magnetic path to ensure characteristics, but by changing the shape of the magnetic material to a variable structure, it becomes possible to vary the back electromotive force to some extent even for a single unit. Based on this idea, there is a prospect of solving the above problems, and the present invention has been completed based on this. That is, the invention claimed in the present application, or at least the disclosed invention, as means for solving the above problems is as follows.

[0009] 〔1〕 A motor comprising a shaft, a rotor attached to the shaft, and a stator, having a configuration in which the back electromotive voltage can be varied. The rotor includes magnets, and one or more axially position-adjustable cylindrical movable back yokes made of a magnetic material are provided in the shaft as members for changing the back electromotive voltage. A variable back electromotive voltage motor characterized by this. 〔2〕 The variable back electromotive voltage motor according to 〔1〕, characterized in that two or more of the movable back yokes are provided, and each movable back yoke can be independently position-adjusted. 〔3〕 The variable back electromotive voltage motor according to 〔1〕, characterized in that the movable range of at least one of the movable back yokes is formed so as to overlap at least a part of the mounting range of the magnet.

[0010] 〔4〕 The variable back electromotive voltage motor according to 〔1〕, characterized in that in addition to the movable back yoke, a cylindrical fixed back yoke with an invariant axial position is provided in the shaft. 〔5〕 The variable back electromotive voltage motor according to any one of 〔1〕, 〔2〕, 〔3〕, 〔4〕, characterized in that the position adjustment of the movable back yoke is formed to be possible in a plurality of steps. 〔5〕 The variable back electromotive voltage motor according to any one of 〔1〕, 〔2〕, 〔3〕, 〔4〕, characterized in that the position adjustment of the movable back yoke is formed to be continuously possible steplessly.

Advantages of the Invention

[0011] Since the variable back electromotive voltage motor of the present invention is configured as described above, according to these, a certain degree of variable back electromotive voltage is possible with a single motor unit, and it is possible to provide a variable back electromotive voltage motor with variable back electromotive voltage without changing the winding or connection method, adding external devices, or requiring demagnetization and remagnetization of the magnets, and the driving range of the motor can be expanded.

[0012] That is, with a single motor, by adjusting to increase the back electromotive voltage, high efficiency and high torque output can be achieved, and by adjusting to decrease the back electromotive voltage, high-speed rotation output can be achieved. In either case, both outputs are possible. In the case of adjusting to decrease the back electromotive voltage, there is also the advantage that regenerative energy can be reduced. Further, such adjustment of the back electromotive voltage can be easily performed even after the motor is manufactured, that is, even at the stage of use by the motor user, and it has higher convenience compared to the method of changing the winding and connection method in which the specifications are fixed at the manufacturing stage.

[0013] Note that the technology disclosed in Patent Document 2 has a common point with the present invention in terms of changing the back electromotive voltage, but it is a method of changing the back electromotive voltage by providing a reactor composed of a reactor core and a reactor coil at both axial ends of the stator, which is different from the method of variable back yoke on the rotor side of the present invention.

Brief Description of the Drawings

[0014]

Figure 1

Figure 1-2

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0015] Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a side sectional view showing the basic configuration of the back electromotive voltage variable motor of the present invention. As shown in the figure, the back electromotive voltage variable motor 10 has a configuration for varying the back electromotive voltage in a motor including a shaft (back yoke) 9, a rotor 6 attached to the shaft 9, and a stator 8. The rotor 8 includes a magnet 7, and in the shaft 9, as a member for changing the back electromotive voltage, a movable back yoke 2 made of a magnetic material and having a cylindrical shape and capable of being adjusted in the axial direction is provided as the main configuration.

[0016] FIG. 1-2 is a side sectional view showing an example of changing the back electromotive voltage in the back electromotive voltage variable motor of the present invention shown in FIG. 1. The back electromotive voltage variable motor 10 having the above-described basic configuration has a movable back yoke 2 at a position where the maximum back electromotive force can be obtained, that is, when the movable back yoke 2 shown in FIG. 1 is adjusted to a position covering the entire mounting range of the magnet 7, compared to when the movable back yoke 2 is adjusted to a position covering only a part of the mounting range of the magnet 7 as shown in (a) in FIG. 1-2, the obtained back electromotive force becomes smaller.

[0017] When the movable back yoke 2 is adjusted to a position outside the mounting range of the magnet 7 as shown in (b) in FIG. 1-2, the obtained back electromotive force becomes even smaller. Thus, the cylindrical movable back yoke 2 provided in the shaft 9 acts as a member for changing the back electromotive voltage, and by adjusting its position in the axial direction, the back electromotive voltage can be changed. As shown in FIGS. 1 and 1-2, the movable range of the movable back yoke 2 can be configured to overlap at least a part of the mounting range of the magnet 7, and this is desirable.

[0018] Note that such a cylindrical movable back yoke 2 provided inside the shaft 9 is not fixed to the shaft 9. Therefore, even if the shaft 9 rotates, the movable back yoke 2 does not rotate following it. Also, since it is not fixed, it can move in the axial direction, enabling position adjustment. The movable back yoke 2 may be in a form slidably provided on the inner wall of the shaft 9 or in a form fitted with an appropriate clearance. The structure of such a movable back yoke is the same in another configuration of the present invention described with reference to FIGS. 2 and later.

[0019] As the material of the movable back yoke 2, any appropriate material can be used as long as it is a magnetic material capable of forming a magnetic circuit. Also, its thickness can be designed appropriately. It is also possible to appropriately design the range of the back electromotive voltage variation depending on the type and thickness of the magnetic material.

[0020] FIG. 2 is a side sectional view showing another basic configuration of the back electromotive voltage variable motor of the present invention. As shown in the figure as the movable back yokes 22 and 23, the back electromotive voltage variable motor 210 of the present invention can be configured to include a plurality of axially position-adjustable cylindrical movable back yokes made of a magnetic material, which are members for changing the back electromotive voltage provided inside the shaft 29. In the figure, a configuration with two movable back yokes 22 and 23 is shown, but it is not limited to this, and three or more may be used. However, two are sufficient to solve the problems intended by the present invention.

[0021] As shown in the figure, the movable back yokes 22 and 23 can be in a nested arrangement relationship. And they can be in a form slidably provided with each other or fitted with a certain amount of clearance so that each can move independently in the axial direction. The state shown in this figure is a state where the shaft (back yoke) 29, the movable back yoke 22, and the movable back yoke 23 are position-adjusted so as to overlap with respect to the entire range of the mounting range of the magnet 27, having a sufficient size as a magnetic circuit, and the back electromotive voltage is maximized.

[0022] In this way, by adopting a configuration in which the movable range of at least one movable back yoke 22 or the like overlaps at least a part of the mounting range of the magnet 27, the variable range of the back electromotive voltage can be increased, and a back electromotive voltage variable motor with a wide range of applications can be obtained. Other position adjustment examples of the present back electromotive force variable motor 210 will be described later with reference to FIGS. 3 and 4.

[0023] The type and thickness of the magnetic material, which is the material, in each of the plurality of movable back yokes 22, 23, etc. can be designed as appropriate. Also, the movable range in the direction of the shaft 29 can be designed as appropriate.

[0024] The position adjustment of the movable back yoke 2 or the like in the present back electromotive voltage variable motor 10 or the like can be configured to be possible in a plurality of steps. That is, a plurality of specific positions for position adjustment are set, and at such a plurality of specific positions, it is a structure that can be temporarily fixed by an appropriate method such as screwing, and the position adjustment can be performed discontinuously and stepwise. For example, in a wind instrument, it is a structure like a recorder or a flute.

[0025] On the other hand, the position adjustment of the movable back yoke 2 or the like may be configured to be continuously possible steplessly. That is, no specific position for position adjustment is provided, and it is a structure that can be temporarily fixed by an appropriate method such as screwing at an arbitrary position, and the position adjustment can be performed continuously and steplessly. For example, in a wind instrument, it is a structure like a trombone.

[0026] FIG. 3 is a side sectional view showing an example of changing the back electromotive voltage in the back electromotive voltage variable motor of the present invention shown in FIG. 2. The state shown in this figure is a position adjustment state in which the movable back yoke 22 is adjusted to a position overlapping the entire mounting range of the magnet 27, while the movable back yoke 23 is adjusted to a position completely outside the mounting range of the magnet 27. That is, with respect to the magnet 27, only the shaft (back yoke) 29 and the movable back yoke 22 overlap, whereby the magnetic circuit is reduced and the back electromotive voltage becomes smaller as compared with the position adjustment state shown in FIG. 2.

[0027] FIG. 4 is a side sectional view showing another example of reverse electromotive force change in the reverse electromotive force variable motor of the present invention shown in FIG. 2. The state shown in this figure is an adjusted state in which both the movable back yokes 22 and 23 are adjusted to positions outside the mounting range of the magnet 27. That is, only the shaft (back yoke) 29 overlaps with the magnet 27, whereby the magnetic circuit is further reduced as compared with the adjusted state shown in FIG. 3, and the reverse electromotive force is further reduced, being the minimum among those shown in FIGS. 2, 3, and 4.

[0028] FIG. 5 is a side sectional view showing the basic configuration of the reverse electromotive force variable motor of the present invention having a fixed back yoke. As shown in the figure, the reverse electromotive force variable motor 510 can be configured to include, in the shaft 59, in addition to the movable back yoke 52, a cylindrical fixed back yoke 55 whose axial position is unchanged. Note that, regardless of the single movable back yoke 22 configuration shown in the figure, as described above, a plurality of movable back yokes may be provided.

[0029] Further, the fixed back yoke 55 is provided so as to overlap the entire mounting range of the magnet 57, but is not limited thereto. Therefore, for example, the fixed back yoke 55 may be provided so as to overlap only a part of the mounting range of the magnet 57.

[0030] The state shown in this figure is a state in which the shaft (back yoke) 59, the fixed back yoke 55, and the movable back yoke 52 are adjusted to overlap with respect to the entire mounting range of the magnet 57, having a sufficient size as a magnetic circuit, and the reverse electromotive force is maximized.

[0031] FIG. 6 is a side sectional view showing an example of reverse electromotive force change in the reverse electromotive force variable motor of the present invention shown in FIG. 5. In the state shown in this figure, the fixed back yoke 55 is in a position overlapping the entire mounting range of the magnet 57, while the movable back yoke 52 is in a position adjustment state where a part of it is adjusted to a position outside the mounting range of the magnet 57. That is, with respect to the magnet 57, only the shaft (back yoke) 59 and the fixed back yoke 55 completely overlap, whereby the magnetic circuit decreases compared to the position adjustment state shown in FIG. 5, and the reverse electromotive force becomes smaller.

Industrial Applicability

[0032] According to the reverse electromotive force variable motor of the present invention, it is possible to provide a reverse electromotive force variable motor with a variable reverse electromotive force configuration without changing the winding or wiring method, or requiring demagnetization and remagnetization of the magnet. Therefore, it is an invention with high industrial applicability in the fields of motor manufacturing, use, and all related fields.

Explanation of Reference Numerals

[0033] 2, 22, 23, 52... Movable back yoke 6, 26, 56... Rotor 7, 27, 57... Magnet 8, 28, 58... Stator 9, 29, 59... Shaft (back yoke) 10, 210, 510... Reverse electromotive force variable motor 55... Fixed back yoke

Claims

1. A configuration with variable back electromotive force in a motor comprising a shaft, a rotor attached to the shaft, and a stator, wherein the rotor is provided with magnets, and one or more axially position-adjustable cylindrical movable back yokes made of magnetic material are provided in the shaft as members for changing the back electromotive force. A variable back electromotive force motor, characterized by the above.

2. The variable back electromotive force motor according to Claim 1, characterized in that two or more of the movable back yokes are provided, and each movable back yoke is independently position-adjustable.

3. The variable back electromotive force motor according to Claim 1, characterized in that the movable range of at least one of the movable back yokes is formed so as to overlap at least a part of the mounting range of the magnet.

4. The variable back electromotive force motor according to Claim 1, characterized in that in addition to the movable back yoke, a cylindrical fixed back yoke with an invariant axial position is provided in the shaft.

5. The variable back electromotive force motor according to any one of Claims 1, 2, 3, and 4, characterized in that the position adjustment of the movable back yoke is formed to be possible in a plurality of steps.

6. The variable back electromotive force motor according to any one of Claims 1, 2, 3, and 4, characterized in that the position adjustment of the movable back yoke is formed to be continuously possible steplessly.

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