JP2616811B2 - Variable speed induction motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a variable speed induction motor, and more particularly, to a single rotor, two stators and the two stators. A voltage phase shift that causes a phase difference between a voltage induced in a rotor conductor portion facing one of the stators and a voltage induced in a corresponding conductor portion of the rotor facing the other stator. The present invention relates to a variable speed induction motor having a so-called two-stator configuration, which can change a rotation speed and a generated torque of a rotor arbitrarily by adjusting a voltage phase shifter.

[Conventional technology]

Methods for controlling the speed of the induction motor include a method of changing the power supply frequency, a method of switching the number of poles of a winding applied to a stator, and a method of controlling a primary voltage. In addition, Japanese Patent Publication No. 27-4357
As described in the publication, the stator is divided into two sets of a fixed stator and a movable stator, each of which has the same winding and is connected to the same power supply. Are connected to each other by a widened wing-shaped conductor at the center and connected at both ends by short-circuit rings, and to the secondary induction voltage induced by rotating the movable stator and secondarily induced by the other fixed stator. A variable-speed induction motor that generates a different-phase current in the same conductor so that the current of the two vectors passes through the rotor conductor as a secondary current and arbitrarily varies the speed of the motor. Since the stator is mounted on the slide bearing so that it can move, the sliding friction between the movable stator and the slide bearing is large, and when the movable stator is rotated to control the speed of the rotor. Requires a large amount of power and a large amount of torque. Exothermic when raw but had heavily taxes the plain bearing due to the expansion of the movable stator due to heat generation. If the movable stator is to be automatically controlled by a small motor, the load becomes considerably large. For this reason, the use of a large-sized rotating motor becomes unavoidable, not only dissipating wasteful large power but also practically not being practical. This tendency became remarkable as the size of the variable speed induction motor increased.

[Problems to be solved by the invention]

In the rotor having a resistance material for short-circuiting the rotor conductor according to the present invention, the phase difference generated by the voltage phase shifter causes a current to flow through the resistance material so that the rotor conductor resistance increases and a large torque is generated. Although it can occur, on the other hand, the heat generated by the resistance material is also large, and the stator formed rotatably due to the influence expands, for example, it becomes impossible to rotate in a sliding bearing system fitted on the outer periphery of the stator. Was gone. The present invention seeks to provide a technique for solving such a problem.

[Means for solving the problem]

In order to achieve the above object, the present invention provides, in a machine frame, a plurality of rotor conductors connected to two rotor cores fixedly mounted on a same rotating shaft at fixed intervals, and An integral cage rotor in which the plurality of rotor conductors are short-circuited to each other by a resistive material between two rotor cores, and two fixed concentrically arranged around the rotor core Two stators each having a winding wound around a stator core, and at least one of the two stators is rotatably formed concentrically with the rotor. In a variable speed induction motor in which a rotating stator is rotated by a mechanism, the rotating stator has a sliding surface between an outer periphery of at least one stator and an inner periphery of a machine frame, and is fixed. A plurality of supports made of an elastic body that absorbs thermal expansion caused by heat generated by the stator; A solution is achieved by fixing one side and sliding the sliding surface of the support on the inner peripheral portion of the machine frame, and forming the at least one stator rotatably concentrically with the rotor. did.

Further, a sliding material such as di-mobilized molybdenum is applied to a sliding surface of the support, or a dense surface material such as tetrafluoride resin is fixed to an inner peripheral surface of a machine frame that slides with the support, or It is also an effective means to fix a metal coated with a sliding material such as molybdenum disulfide to the inner peripheral surface of the machine frame that slides on the support.

Further, a solution is provided by interposing a rolling element on the sliding surface.

The variable speed induction motor of the present invention can be formed in either a single phase or a three phase.
It can be applied to any type such as double cage type, deep groove cage type, special cage type, and wound type.

(Operation)

The operation of the variable speed induction motor configured as described above is as follows. That is, a plurality of elastic supports having sliding surfaces are provided on the outer periphery of the stator, and the stator slides on the inner peripheral surface of the machine frame via the elastic support.

Furthermore, a sliding material is applied to the sliding surface of the support or the inner peripheral surface of the machine frame, or a dense surface material is fixed, and a rolling element is interposed. Unlike the configuration in which the stator is used, since the stator is supported by a plurality of elastic supports, the fitting pressure is not directly generated by the conventional fitting, and the sliding surface or the rolling element is stably rotated. It can be. Furthermore, in addition to the above-described sliding, the rotation is performed with the rolling element interposed on the sliding surface, so that the rotating stator can be rotated with a smaller force than the above-described configuration. It is possible to reduce the size of the driving device and the like.

In addition, this variable speed induction motor, by the action of the resistance material,
While it can produce a large torque, it also generates a large amount of heat,
If a configuration is adopted in which a ball bearing or a roller bearing is fitted to the outer peripheral portion of the stator for rotation of the stator and is mounted on a machine, the rotatably formed stator expands to expand the ball bearing. Or, a large force is applied to the roller bearing and a large force is also applied to the machine frame.If the expansion is large, the ball bearing or roller bearing may be damaged or the machine frame may be damaged, or the ball bearing or roller bearing stator may be damaged. Or, the contact point with the machine frame side was worn in conjunction with the action of vibration during operation of the motor, but in the present invention, since the support supporting the stator has elasticity, the thermal expansion is And the expansion does not directly affect the sliding surface or the rolling element. Therefore, tension with the inner peripheral surface of the machine frame due to expansion does not occur, and the influence of thermal expansion on the rotating stator due to the expansion can be ignored.

〔Example〕

First, the configuration of the variable speed induction motor 1 to which the present invention is applied will be schematically described with reference to FIG. 1 (the same applies to FIG. 2). Rotor cores 2A and 2B are mounted on the rotor shaft 3 of the rotor 2 with a certain interval therebetween. A non-magnetic core portion 2C is provided between the rotor cores 2A and 2B. A plurality of rotor conductors 4 are provided in a cage shape in a communication manner over the rotor cores 2A, 2B, and both ends thereof are short-circuited by short-circuit rings 5, 6.
Non-magnetic core portion 2C between rotor conductors 4 (between rotor cores)
Are interconnected (resistance short circuit) by the resistance material R. The rotor 2 integrally formed in this manner is rotatable in the motor frame 10 because both ends thereof are supported by bearings 7A and 7B.

The stators 12A and 12B are arranged side by side on the inner wall surface of the machine frame 10 so as to face the respective outer peripheral surfaces of the rotor cores 2A and 2B. Further, the cylindrical machine frame 10 and the bearing plates 40A, 40B on both sides of the machine frame are provided with bolts 19A, 1B.
It is assembled integrally by tightening 9B. Further, ventilation holes 41A, 41B are formed in the bearing plates 40A, 40B.

In the case of the present embodiment, the stator 12B is a fixed stator fixed to the inner wall surface of the machine frame. The stator 12A includes a support 50 provided between the outer periphery and the inner peripheral surface of the machine frame, the small motor 15 and the gears 16 and 17. Stator 12A has multiple supports
Since it is formed so as to be rotatable concentrically with the rotating shaft 3 by 50, it is a rotating stator. The rotating stator 12A and the fixed stator 12B have ventilation holes 30A and 30B, respectively. A blower 21 having an open top is fixedly surrounding the open air outlet 20 at the upper center of the machine frame 10, and a fan motor 22 is supported by the blower 21.
A fan 23 is mounted on a rotation shaft 22. The gear 17 is fitted on the outer peripheral surface of the stator core, and the gear 16 and the small motor
The rotation mechanism 18 is formed by 15. This allows the fixed stator
It can rotate relative to 12B. By operating this rotating mechanism, specifically, a small motor
By rotating 15 by an arbitrary amount, a phase difference occurs in the voltage induced in the rotor conductor portions corresponding to each of the two stators of the rotor. That is, in the illustrated embodiment, this rotating mechanism constitutes the voltage phase shift device 18. In addition, each stator 12A, 12B
The connection of the stator windings 13A and 13B wound around the power supply to the power supply may be either serial or parallel. In addition, although the voltage phase shifter is shown by a rotating mechanism, it may be a combination of pure electric means such as interposing a phase shifter of a connection switching type of a stator winding and a rotating mechanism. .

The first embodiment will be described below with reference to FIG. The entire configuration is the same as that described above, and will not be described.

In FIG. 1, a rotating stator 12A is formed by a support 50 so as to be rotatable concentrically with the rotating shaft 3. More specifically, a plurality of supports 50 are interposed between the rotating stator 12A and the inner peripheral surface of the machine frame facing the rotating stator 12A, and one of the supports 50 is placed on the outer peripheral surface of the rotating stator. And the other slides on the inner peripheral surface of the machine frame. As described above, since the plurality of supports 50 are uniformly fixed to the outer peripheral surface of the rotary stator 12A and slidably contact the inner peripheral surface of the machine frame, the rotary stator 12A is concentric with the rotary shaft 3. It becomes freely rotatable. The support 5 is formed like an octopus from the outer periphery of the rotating stator 12A.
0 is the form that can be done. The sliding surface of the support 50 is prevented from shifting left and right by the collar 53 from the bearing plate 50A side.

Next, the sliding surface will be described. The sliding surface between the support 50 and the inner peripheral surface of the machine frame is provided with a sliding material, a dense surface material, or a sliding material provided with a sliding material. (Third
The sliding material on the sliding surface of the support 50 is electroless nickel plating + Sic, nickel alloy coating compounded with tetrafluoride resin, molybdenum disulfide, hard chrome plated and then impregnated with Teflon. is there. When the dense surface material is fixed to the inner peripheral surface of the machine frame, examples of the dense surface material include tetrafluoride resin, nylon containing molybdenum disulfide, and sintered metal containing graphite.
Further, there is a method in which the above-mentioned sliding material is applied to a metal and fixed to the inner peripheral surface of the machine frame as a dense surface material.

The support 50 is made of an elastic material, but a familiar example is a spring material. The sliding stator of the support 50 supports the own weight of the rotating stator and adheres to the inner peripheral surface of the machine frame. Further, when the rotating stator expands due to the heat generated by the resistance material R,
A material having elasticity to absorb this will be selected. Various methods and shapes can be selected according to the material of the elastic body, the plate thickness, the surface area, the treatment, and the like. (FIG. 5) Although the sliding has been described above, the interposition of the rolling element on the sliding surface can provide more effects than the sliding.
Next, a second embodiment will be described with reference to FIG. The entire configuration is the same as in the first embodiment, and a description thereof will be omitted.

A plurality of supports 50 are interposed between the rotating stator 12A and the inner peripheral surface of the machine frame facing the rotating stator, and one of the supports 50 is uniformly fixed to the outer peripheral surface of the rotating stator. The other is in contact with the inner peripheral surface of the machine frame. The contact portion of the support 50 is prevented from shifting left and right by the collar 53 from the bearing plate 40A side. A rolling element 60 is provided at a contact portion of the support 50. In this embodiment, the rolling element 60
Using rollers. (FIG. 4) In the above configuration, the rotating stator 12A supported by the rotatable support 50 formed concentrically with the rotating shaft 3 is
It is adjusted and set by the small motor 15 of the voltage phase shifter 18.
The rotation of the rotating stator 12A causes a phase shift in a rotating magnetic field generated between the rotor and the stator, thereby increasing or decreasing the voltage induced in the rotor conductor, thereby increasing the rotational speed of the rotor. Can be changed arbitrarily. When the rotating stator 12A is further rotated, the rotor conductor 4 provided in a communicating manner between the rotors 2A and 2B has an integral structure short-circuited by the resistance material R. A current flows due to the phase difference, the resistance of the rotor conductor 4 increases, and a large torque can be generated.

In the above variable speed induction motor, the support 50 is fixed to the stator, and the support 50 is slid on the inner peripheral surface of the machine frame or a rolling element is interposed between the support 50 and the inner peripheral surface of the machine frame. The stator is formed concentrically with the rotor shaft 3, and fitting from the machine frame inner surface by fitting with a bearing interposed between the machine frame inner surface and the rotating stator outer peripheral surface as in the conventional example. The surface pressure disappears due to the elasticity of the support 50, and the rotation stator can be rotated by a small motor. Further, in order to support the rotating stator 12A with a plurality of supports 50, a plurality of supports 5
The space between 0 is a space, and a sufficient ventilation path for cooling inside the machine frame can be secured. Further, when a large torque is generated in the variable speed motor, heat generated by the resistance material of the rotor conductor is accompanied by thermal expansion of the rotating stator. The squeaking or immovability can be ignored by providing a gap between the support of the rotating stator and the inner surface of the machine frame facing the rotating stator, and by supporting the stator described above in detail with the support.

〔The invention's effect〕

Since the present invention is configured as described above, the rotation of the stator can be performed with a small force, and the ventilation path can be provided between the plurality of supports even when the operation is performed for a long time or at a high torque and a large amount of heat is generated. Can be sufficiently secured, and the rotation of the stator does not hinder at all because the rotating stator is supported by the elastic body.
This made it possible to smoothly operate a variable speed induction motor with excellent torque characteristics and efficiency.

[Brief description of the drawings]

1 is a side sectional view of a variable speed induction motor according to a first embodiment of the present invention, FIG. 2 is a side sectional view of a variable speed induction motor according to a second embodiment of the present invention, and FIG. FIG. 4 is a detailed view of the rolling element portion of the second embodiment, and FIG.
The figure shows various shapes of the support, and FIG. 6 is a front sectional view of the rotating stator part of the variable speed induction motor according to the present invention. In the figure, 2 ... rotor, 2A, 2B ... rotor core, 2C
… Non-magnetic core, 3… Rotor shaft, 4… Rotor conductor, 5, 6… Short circuit ring, 7A, 7B… Bearing, 10… Machine frame, 11…
... machine frame side bearing, 12A ... rotating stator, 12B ... fixed stator, 13A, 13B ... stator winding, 14 ... stopper, 15 ...
... Small motor, 16,17 ... Gear, 18 ... Voltage phase shifter, 1
9A, 19B …… Bolt, 20 …… Outlet, 21 …… Blower, 22…
… Fan motor, 23 …… Fan, 30A, 30B, 30C, 40A, 40
B ... vent, 50 ... support, 51 ... sliding material, 52 ...
Close surface material, 53 ... Color, 54 ... Close surface material with sliding material, 60 ... Rolling element.

Claims (5)

(57) [Claims] In a machine frame, a plurality of rotor conductors communicating with two rotor cores fixedly mounted on the same rotation shaft at fixed intervals are provided, and the two rotor cores are provided. A winding is wound around an integral cage rotor in which the plurality of rotor conductors are short-circuited to each other by a resistance material, and two stator cores arranged concentrically with the rotor core. Two wound stators are provided, and at least one of the two stators is rotatably formed concentrically with the rotor and rotated by a rotation mechanism. In a variable speed induction motor having a rotating stator, the rotating stator has a sliding surface between an outer periphery of at least one stator and an inner peripheral portion of the machine frame, and is thermally expanded by heat generated by the stator. A plurality of supports made of an elastic body that absorbs the heat are provided, and one of the supports is fixed to the outer periphery of the stator, and the inner periphery of the machine frame is fixed. The sliding surface of the support in sliding contact with the,
A variable speed induction motor, wherein the at least one stator is rotatably formed concentrically with the rotor. 2. The variable speed induction motor according to claim 1, wherein a sliding material such as mobilized molybdenum is applied to a sliding surface of said support. 3. A dense surface material such as tetrafluoride resin is fixed to an inner peripheral surface of the machine frame which slides on the support.
Or the variable speed induction motor according to 2. 4. A variable speed induction motor according to claim 1, wherein a metal material provided with a slip material such as molybdenum is fixed to the inner peripheral surface of the machine frame which slides on the support. . 5. The variable speed induction motor according to claim 3, wherein a rolling element is interposed on a sliding surface.