JPH0226294A - Variable speed induction motor - Google Patents

Abstract

PURPOSE:To prevent the hindrance to the rotation of a stator due to absorbing of the expansion of a bearing with heat generation through making the rotation of said rotating stator the sliding part of a face bearing where the end face of a ring spreads obliquely outward. CONSTITUTION:A main bearing 50 having a sliding face, where the end face of a ring spreads obliquely outward, is stuck to one side of the outer periphery of a rotating stator 12A. The inner peripheral face of a machine frame facing a rotating stator 12A is internally provided with a face bearing 51 having a sliding face coming into sliding contact with the sliding face of said face bearing 50. Consequently, even if the face bearing 50 expands due to heat generated when a large torque is produced by the action of a resistance material, said expansion spreads in the direction of faces coming into sliding contact with each other so that the adverse influence of said expansion on the face bearing is neglected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a variable speed induction motor, and more particularly, to a variable speed induction motor having a single rotor and a plurality of stators. By rotating the rotor, a voltage is induced in a rotor conductor portion facing one of the plurality of stators and a voltage is induced in a corresponding conductor portion of the rotor facing the other stator. The present invention relates to a so-called variable speed induction motor having a multi-stator configuration, which can create a phase difference between voltages and arbitrarily change the rotational speed and generated torque of a rotor.

[Conventional technology]

Methods for controlling the speed of an induction motor include changing the power supply frequency, switching the polarity of the windings applied to the stator, and controlling the -order voltage. In addition, special public service
The technology described in Publication No. 57 divides the stator into two sets, a fixed stator and a movable stator, each with the same winding and connected to the same power supply, and also divides the rotor into two sets to prevent rotation. The child conductors are connected at the center by a separate conductor with a wide width, and at both ends by a short-circuit ring, and the movable stator is rotated to generate a secondary induced voltage induced by the other fixed stator. On the other hand, a variable speed induction motor generates different phase currents in the same conductor, so that the sum of the two vectors of current flows through the rotor conductor as a secondary current, and the speed of the motor can be arbitrarily varied. Since the movable stator is attached to a sliding bearing and is configured to move, the sliding friction between the movable stator and the sliding bearing is large, and the movable stator is rotated to control the speed of the rotor. This requires a large amount of force, and if the movable stator were to be automatically controlled by a small motor, it would result in a considerable load. For this reason, the use of a large rotation motor is unavoidable, which not only wastes a large amount of power and radiates heat, but is also practically impractical. This tendency became more pronounced as the variable speed induction motor became larger.

[Problems to be Solved by the Invention] In the rotor having a resistive material that short-circuits rotor conductors according to the present invention, any one of the plurality of stators is rotated to form a voltage phase shift device, Due to the phase difference caused by this voltage phase shifting device, current flows through the resistor material connected to the rotor conductor, so that the rotor conductor resistance increases and a large torque can be generated. The heat generation of the resistive material is also large, and as a result, the rotatable stator expands, making it impossible to rotate, for example, in a sliding bearing type. The present invention aims to provide a technique to solve such problems.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a plurality of rotor conductors installed in a continuous manner on a plurality of rotor cores that are pivotally attached to the same rotating wheel at regular intervals, and a plurality of rotor conductors are connected to each other. an integral rotor short-circuited and connected between the plurality of rotor cores by a resistance material; and a stator core facing each rotor core of the rotor, arranged coaxially with the rotor. A plurality of stators are provided in the machine frame, and one of the plurality of stators is provided with a slide on one of the outer circumferences of at least one of the plurality of stators so that the end face of the ring extends diagonally outward. A surface bearing having a sliding surface is fixed, and a surface bearing having a sliding surface that comes into sliding contact with the sliding surface of the surface bearing is installed on the inner circumferential surface of the machine frame facing the at least one stator, The solution is achieved by forming the at least one stator to be rotatable concentrically with the rotor to form a rotating stator.

The variable speed induction motor of the present invention can be formed into either a single-phase or three-phase type, and the rotor can have a rotor shape such as a normal squirrel cage type, a double squirrel cage type, a deep groove cage type, a special squirrel cage type, or a wound type. The conductor used in the description of the present invention is a general term for the conductor installed in the squirrel-cage rotor core and the winding wound around the wire-wound rotor core. It is something to do.

[For production]

The operation of the variable speed induction motor configured as described above is as follows. In other words, the rotation of the rotary stator is caused by sliding on a surface bearing, for example, with the end face of the ring expanding diagonally outward, so when a large torque is produced by the action of the resistive material, as in this variable speed induction motor, Even if the surface bearing expands due to the heat generated, the expansion spreads in the direction of the surfaces that are in sliding contact.
The effect of expansion on the surface bearing is ignored, and if a ball bearing or roller bearing is fitted to the outer periphery of the stator and attached to the machine frame for rotation of the stator, as in the conventional example. When the rotatable stator expands, a large force is applied to the ball bearing or 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 may be damaged. The present invention eliminates the problems of damage to the frame side and wear of the contact points of ball bearings or roller bearings with the stator or machine frame side due to vibrations during motor operation.

〔Example〕

Examples will be described below with reference to FIGS. 1 and 2.

First, the configuration of a variable speed induction motor 1 to which the present invention is applied will be schematically explained. Rotor cores 2A and 2B are mounted on the rotor shaft 3 of the rotor 2 at regular intervals. A non-magnetic core portion 2C is provided between the rotor cores 2A and 2B. A plurality of rotor conductors 4 are installed in a cage shape on the rotor cores 2A, 2B in communication across the outer end sections thereof, and both ends thereof are mutually short-circuited by a short-circuit ring 5.6. be done. The rotor conductor 4... is a non-magnetic core portion 2C and is made of a resistive material r.
are interconnected (resistive short circuit). The rotor 2 thus constructed in one piece has both ends bearing the bearings 7A.
, 7B, it becomes rotatable within the motor frame 10. Further, ventilation holes 25A and 25B are provided at appropriate locations in the rotor core 2.3.

Stators 12A and 12B are arranged in parallel on the inner wall surface of the machine frame 10, facing each outer peripheral surface of the rotor cores 2A and 2B. Furthermore, as is clear from the drawings, the cylindrical machine frame 10 and the bearing plates 40A, 40B on both sides of the machine frame are connected to bolts 19A, 19B.
It can be assembled integrally by tightening. Further, ventilation holes 41A and 41B are provided in the bearing plates 40A and 40B.

In the case of this embodiment, the stator 12B is a fixed stator fixed to the inner wall surface of the machine frame. The stator 12A is concentric with the rotating shaft 3 by being constituted by a surface bearing 50, 51 interposed between the outer peripheral surface of the stator and the inner peripheral surface of the machine frame, a small motor 15, and gears 16, 17. The stator 12A is a rotating stator because it is designed to be freely rotatable.

(The surface bearing will be described later.) Note that ventilation holes 30A and 30B are provided in the rotating stator 12A and fixed stator 12B, respectively. A blower cylinder 21 with an open top is fixed to the center upper part of the machine frame 10, surrounding the open air exhaust port 20.
1 supports a fan motor 22, and the motor 22
A fan 23 is attached to the rotating shaft of the fan 23 .

The gear 17 is fitted onto the outer peripheral surface of the rotating stator 12A, and the gear 16 and the small motor 15 form a rotating mechanism 18. This allows rotation relative to the fixed stator 12B. By operating this rotation mechanism, specifically by rotating the small motor 15 by an arbitrary amount, a phase difference is generated between the rotor conductor portions corresponding to each stator of the rotor. That is, in the illustrated embodiment, this rotation mechanism constitutes the voltage phase shifter 18.

Reference numeral 60 denotes a solenoid for controlling the entry and exit movement of the protruding piece, and the solenoid 60 is mounted on the machine frame 14, and the protruding piece is freely engaged with the gear 17 fitted to the rotary stator 12A.
The rotating stator 12A is fixed so that it does not rotate except when necessary.

Note that the stator windings 13A, 13B wound around the stators 12A, 12B may be connected to the power source either in series or in parallel. In addition, although a voltage phase shifting device using a rotating mechanism is shown, a combination of purely electrical means such as a phase shifter that switches the connection of the stator winding and a rotating mechanism may also be used. .

The surface bearing 50.51 will be explained based on FIGS. 3 and 4.

The surface bearing 50 fixed to the outer periphery of the rotary stator 12A has, for example, a ring with both end surfaces extending diagonally outward.
It has a sliding surface that forms a certain slope. Further, the rotary stator 12
The surface bearing 51 fitted on the inner peripheral surface of the machine frame facing A has a sliding surface that slides in contact with the sliding surface of the surface bearing 50, and by sliding on the sliding surface, the rotating stator 12A is rotated. It can freely rotate concentrically with the rotor 2. At this time, the surface bearing 50 and the surface bearing 51 are in contact only at their sliding surfaces, and the other portions have a certain gap between them. Further, one or more surface bearings 50 are fixed to the outer periphery of the rotating stator 12A. The gear 17 may be fitted onto the outer periphery of the surface bearing 50, or the gear 17 may be formed on the surface bearing 50 itself. Symbol 53 is surface bearing 5
1 is a stopper 53 for fixing it.

As mentioned above, the sliding surface forms a certain slope, but the slope varies depending on the coefficient of volumetric expansion of the material of the surface bearings 50 and 51, and is determined experimentally.

Next, we will discuss the lubrication of this surface sliding. In this embodiment, an oil groove 52 for oil lubrication is provided in the surface bearing 51 to show an oil-supplied lubrication method, but there is also a method in which one or both of them are oil-impregnated bearings and an oil-free type is used. Use known sliding surface lubrication methods. It is also possible to eliminate the need for oil by coating the sliding surfaces.

The surface bearing of the above configuration is accompanied by thermal expansion due to heat generation from the resistive material and the stator during high torque generation, startup, and long-term operation of the variable speed induction motor according to the present invention. .51 also expands. In the case of the present invention, the sliding surface of the surface bearing has a certain slope, for example, with both end surfaces of the ring expanding outward, so that the expansion of the surface bearing 50, 51 due to heat generation is As shown in the figure, the sliding surface is shifted in the plane direction, and the immobility of the bearing due to the fitting pressure with the machine frame, which is conventional, can be ignored.

In the above configuration, the rotatable rotary stator 12A, which is formed concentrically with the rotor shaft 3, is adjusted and set by the small motor 15 of the voltage phase shifter 18. Rotating stator 12
The rotation of A causes a phase shift in the rotating magnetic field generated between the rotor and stator, and by controlling the increase or decrease of the voltage induced in the rotor conductors, the rotation speed of the rotor can be changed arbitrarily. . When the rotary stator 12A is further rotated, the rotor conductor 4 installed in communication between the rotors 2A and 2B is connected to the resistive material R due to the integral structure short-circuited by the resistive material R. A current flows due to the phase difference, and the resistance of the rotor conductor 4 increases, which can generate large torque and ripple.

In the variable speed induction motor described above, due to the fitting between the inner surface of the machine frame and the outer circumferential surface of the rotary stator with a bearing interposed between the inner surface of the machine frame and the outer circumferential surface of the rotary stator, the pressure on the fitting surface from the inner surface of the machine frame is reduced by the sliding surface of the surface bearing. It is absorbed by the deviation in the plane direction, and the rotary stator can be rotated by a small motor.

Furthermore, when a large torque is generated in a variable speed electric motor, the rotary stator is thermally expanded due to the heat generated by the resistive material of the rotor conductor. Immobility becomes negligible by supporting the stator as detailed above.

〔Effect of the invention〕

Since the present invention is constructed as described above, the stator can be rotated with a small force, and even if the stator is operated for a long time or at high torque and generates a large amount of heat, the stator does not rotate at all. This made it possible to smoothly operate a variable speed induction motor with excellent torque characteristics and efficiency without any problems.

[Brief explanation of the drawing]

Figure 1 is a side sectional view of a variable speed induction motor according to the present invention, Figure 2 is a front sectional view, Figure 3 is a detailed view of section A in Figure 2, and Figure 4 is a detailed view of section A in Figure 2.
The figure is a detailed view of part B in Figure 3, 1... variable speed induction motor, 2... rotor, 2A, 2B... rotor core, 2C... non-magnetic core part, 3...rotor shaft,
4...Rotor conductor, 5゜6...Short ring, 7A, 7B
...Bearing, 10...Machine frame, 12A...Rotating stator, 12B...Fixed stator, 13A, 13B...Stator winding, 15...Small motor, 16.17 ...Gear, 18...Voltage phase shifter, 19A, 19B...Volt, 20...Exhaust port, 21...Blower cylinder, 22...
Fan motor, 23...Fan, 25A, 258.
30A, 30B, 300.40A, 40B...Vent hole, 50.51...Face bearing, 52...Oil groove, 53
...Stopper 60...Solenoid, r...Resistance material.

Claims (1)

[Claims] A plurality of rotor conductors are installed in a continuous manner on a plurality of rotor cores that are mounted on the same rotating shaft at regular intervals, and the rotor conductors are connected between the plurality of rotor cores. An integral rotor short-circuited by a resistive material, and a plurality of stators arranged in parallel coaxially with the rotor, each having a stator core facing each rotor core of the rotor. A surface bearing is provided in the machine frame and has a sliding surface with a ring end face extending diagonally outward to one of the outer peripheries of at least one of the plurality of stators, and A surface bearing having a sliding surface that makes sliding contact with the sliding surface of the surface bearing is installed on the inner peripheral surface of the machine frame facing one stator, and the at least one stator is connected to the rotor. A variable speed induction motor characterized by a rotary stator formed concentrically and rotatably.