JPH0265642A - Rotor and its manufacture - Google Patents

Abstract

PURPOSE:To vary the speed over a wide range in high torque by inserting a conductor with insulating coating into the slots of two rotor cores on the same shaft, by short-circuiting the outside ends of the cores with metal rings and by coupling their inside ends through a resistance material. CONSTITUTION:Two rotor cores 2 and 3 having formed slots are engaged with a common shaft 4. Bar conductors 5 with insulated coating are inserted into the slots to form rotors 2A and 3A. The conductors 5 are short-circuited with metal rings 6 and 7 at the outside ends of iron cores 2 and 3. On the inside of cores 2 and 3 bar conductors 5 are coupled through a resistance material h with conductors 55. A stator 25 corresponding to the rotor 3A is secured to a machine frame 14. It is turnable circumferentially and controls rotating speed. A speed variation mechanism in high frequency and a wide range can thereby be manufactured at low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a variable speed induction lightning rotor having good torque characteristics and efficiency and easy speed control, and a method for manufacturing the rotor.

(Prior art and its problems) Methods for controlling the speed of an induction lightning VJ machine: - How to change the power supply frequency - How to change the number of poles of the motor - How to change the power supply voltage - How to change the secondary resistance of a wound motor However, in order to realize the above method, an expensive conversion device is required, or additional equipment is required for the conversion device, and even if the above method is realized, the speed change is difficult. Some are not smooth, others have smooth gear shifts but are inefficient and have low torque in the low speed range, others require maintenance and inspection of consumables, and are only used for induction motors with limited configurations. There were various problems such as not being able to do so.

To address the above problems, for example,
The technology is disclosed in Publication No. 29005, which shorts two sets of rotor cores installed coaxially, two sets of stators, a squirrel cage conductor, and a squirrel cage conductor. This is a twin-iron core squirrel-cage electric motor that is equipped with a high-resistance element that shifts the phase of the stator windings by 180 degrees during startup, and then feeds power while matching the phases during operation after startup.

Furthermore, another example proposed in Japanese Patent Application Laid-Open No. 49-86807 is an asynchronous electric motor having a stator including multilayer windings and a squirrel cage rotor.

However, the one published in Japanese Patent Application Laid-Open No. 54-29005,
Although it is recognized that the startability is improved, it cannot be used as a power source for a load that requires continuously variable speed. Furthermore, in the device that provides a phase difference as disclosed in Japanese Patent Application Laid-open No. 49-86807, the torque is small except when the phase angles of the two stators are in the same phase, and the operation stops immediately when a load is applied. It was not provided.

In order to solve many of the problems mentioned above, the present applicant has applied for the prior application of Japanese Patent Application Laid-Open No. 62-260590 and Japanese Patent Application Laid-open No. 63-177790.
This method provides a low-cost, high-efficiency, and high-strength induction motor for producing an induction motor that provides a phase shift in the rotating magnetic field between two stators to diversify torque and improve variable speed or starting performance. The rotor manufacturing method has made it possible for the variable speed induction motor related to the rotor to obtain high torque over a wide range of variable speeds and a wide range of speeds.

However, the rotor of a general-purpose electric motor is generally formed into an integral rotor by polymerizing and connecting multiple silicon steel plates whose end surfaces have been treated with phosphoric acid insulation such as Carlite. Even if the conductor insertion holes were not insulated, the proportion of the current flowing through the conductors flowing through the core was small, and no special treatment was required. However, the integrated rotor with multiple stators In order to supply power with a large phase difference between the stator windings at the time of starting, for example, by 180°, the current that flows back through the conductors leaks from the conductor insertion holes to the rotor core and is absorbed, which reduces the starting torque. However, in order to use it as a practical electric motor that can control the speed at any speed over the entire rotation speed from startup to maximum rotation, it is necessary to use a rotor core and rotation that can be easily implemented. It is necessary to provide insulation from the child conductor during rotor manufacturing. In particular, manufacturing the rotor of a variable speed induction motor is difficult due to its complexity, strength, and need for insulation, making it difficult to manufacture the rotor in an integrated manner efficiently and at low cost.

(Object of the Invention) The present invention is intended to solve the above-mentioned problems,
The objective is to obtain a unique torque characteristic that cannot be achieved by the sum of each of the components disclosed in Publication No. 6807, and by solving the problems of the manufacturing method described above, the speed control region can be widened and the speed control can be made stepless. We have developed a variable speed induction motor that can be set to any desired speed, can be started with any torque, and has excellent torque characteristics and efficiency over the entire speed range from the starting point to the maximum rotational speed. 1986-26059 and JP-A-63-188599
It is proposed as a number.

The present invention is intended to further improve the above-mentioned proposed technology, by insulating the conductor inserted into the rotor core to prevent current from leaking from the conductor to the rotor core, and to reduce torque during startup and arbitrary speed rotation. The purpose is to provide technology that improves characteristics and efficiency.

Measures to solve problem c) Install conductors insulated with hollow or solid alumite, etc., made of aluminum as a base material, into each hole of two rotor cores with multiple holes. , caulk the conductor at both ends or one side of the rotor core, cast aluminum by die-casting on each of the rotor cores equipped with the conductor, and short-circuit it on one side of the rotor core while fusing it with the conductor. or an end on the other side to form an integral rotor part, and the engagement of the end with a conductor separate from the conductor between the ends of the two rotor parts; The four conductors are connected in a continuous manner by the other conductor to form a physical squirrel cage quantum trochanter, and a connecting material is welded to the separate conductor to short-circuit between the four separate conductors. This was used as a means of solving the problem.

(Function) In the rotor according to the present invention, the conductor installed in the rotor core is a hollow shaft or solid shaft made of aluminum as a base material, and the outer periphery of the conductor is insulated with alumite or the like. By installing the rotor core, it has sufficient insulation to withstand high temperatures during casting, or heat generation due to the high torque generated at low speeds of variable speed induction motors.Also, the rotor core is made of aluminum by die casting. When doing so, the rotor part is completed by fusing the base material of the conductor and physically forming the ends and the short-circuit ring, and the rotor conductor is connected between the ends of the rotor core between the rotor cores. The rotor can be manufactured efficiently by integrally forming the rotor by fitting different separate conductors and ends,
Made at low cost. By the method of fixing the end of the rotor core and the separate conductor by fitting, the separate conductor is
Since any of aluminum, copper, steel, stainless steel, copper-nickel alloy, or iron can be used, the resistance of the rotor conductor can be adjusted and the torque characteristics can be adjusted according to the load. Furthermore, by employing the method of fixing by fitting, a well-balanced rotor can be manufactured integrally without distortion caused by welding or the like.

〔Example〕

Examples will be described with reference to FIGS. 1 and 2. Reference numeral 1 in FIG. 1 is a variable speed induction motor 34 according to the present invention, and the induction motor has the following configuration.

A rotor core 2.3 made of an iron core is mounted on the rotor shaft 4 at an arbitrary interval, and the rotor core is connected to the rotor core 2, 3.
Among the plurality of conductors 5 installed in each, a plurality of adjacent conductors 5 are combined into a set, and one end thereof is connected to short-circuit rings 6 and 7.
The ends 51 were formed by connecting the plurality of conductors as a set on the other side. Furthermore, the rotor 8 is connected to a set of conductors between the rotor cores 2, 3, i.e. of the rotor cores 2, 3! /i; conductor 5 for part 51
5 are integrally connected by connecting them in a continuous manner. The conductors 55 connected in communication between the rotor cores 2.3 are short-circuited through a resistive material r...for example, a copper-nickel alloy, a nickel-chromium alloy, an iron-chromium alloy, or stainless steel.

Further, the rotor cores 2 and 3 are provided with a plurality of ventilation cylinders 12 . Further, the plurality of resistance materials r... can be formed into a U-shape projecting from the outer periphery of the rotor, and can be formed in the cooling effecting body 13 as an arbitrary cooling stirring body.

On both sides of the resistive material r, shielding plates 52 are provided to which a heat insulating material is fixed, which is based on the heat generated by the resistive material r.

Bearing discs 15, 168 provided on both sides of the cylindrical d frame 14
Assemble G and rotor 8 integrally with bolts 17 on both sides.
Cooling impellers 19°20 are installed on both sides of the rotor shaft 4.
Bearings 21, 21 with both ends fitted in bearing discs 15 and 16
The rotor 4 is rotatably supported.

As shown in FIGS. 1 and 2, a rotary stator 31 having a winding 22.23 on its outer side concentrically with respect to the rotor core 2.3 and a second stator 25 are arranged facing each other. set, machine frame 14
A stop ring 28 is provided with a sliding bearing 26 between the rotating stator 31 and the rotating stator 31, and the sliding bearing 26 is fitted into the machine frame 14.
The second stator 25 is a fixed stator fixed to the inner wall surface of the machine frame 14. A gear 33 is fitted on the outer peripheral surface of one side of the rotating stator 31.
A drive gear 36 is pivotally attached to a small motor 35 for forward and reverse rotation formed by a drive device 29 fixedly installed on the outer periphery of the machine frame 14, and a plurality of exhaust ports 39 are bored in the outer periphery of the machine frame 14. Installed and bearing! ? 15 and 16 are provided with a plurality of through holes 40.... The stator 25.31 is also provided with a plurality of ventilation barrels 24.32 communicating with both sides of the stator.

Between the rotor cores 2 and 3, the rotary stator 31 mounted on the sliding bearing 26, and the second stator 25. A space 66 formed with the d frame 14 is formed in the ventilation shell 67, a plurality of openings are opened in the machine frame 14 to communicate with the ventilation shell 67, and the plurality of openings are used as an arbitrary number of ventilation ports. 68 and an exhaust port 69. A motor 72 pivoted to a windmill 71 is attached to a blower body 70 to form a blower device 73. The blower device 73 is fixed to the machine frame 14, and the air suction part 74A of the blower device 73 is connected to the exhaust port 69 to communicate with the ventilation shell 67, and outside air is introduced from the other side of the exhaust port 69. Port 68 Ventilation barrel 6
7, and the air blower 1170 is provided with an air exhaust portion 74B. In addition, the air outlet 69 includes a cooler, a condenser,
A refrigerant gas or various other refrigerant devices may be connected directly or via a conduit.

A driving center 36 partially inserted into the machine frame 14 through the opening 37 is engaged with the gear t7-33 fitted to the rotary stator 31, and a switch is provided to form the driving vJ device 29. It is connected to a rotating stator 31 via a rotating mechanism 30 consisting of a small motor 35, a gear 3S'3, and a driving gear 36, and the rotating stator 31 is rotatable and fixed to the machine frame 14. A rotary stator 31 that is rotatable in relation to the second stator 25 is provided in the voltage phase shifter 100.

As the rotor 8 rotates, outside air is sucked into the machine frame 14 by the cooling impeller 19° 20 through the ventilation holes 40 bored in the bearing discs 15 and 16, and the cooling impeller 19 winds the outside air. line 2
2. The rotor core 2, conductors 5, etc. are cooled and removed to the outside of the machine frame 14 through the exhaust holes 39. The surplus air is made to flow into the ventilation shell 12... and the rotor cores 2 and 3 are
is cooled and combined with the air sucked from the bearing disc 16 to form the winding 23. The second stator 25 is ventilated and cooled, and the machine frame 1
4 is discharged from the winding holes 39B..., and the windings 22.23
, rotor cores 2, 3, conductors 5, and so on in a stable manner.

Reference numeral 38 is a solenoid that controls the entry and exit movement of the protruding piece.
1 to v! ! It is freely engaged with the attached gear 33, and acts as a stopper to prevent the stator from easily turning unnecessarily due to the reaction to the stator when the torque is generated.

As shown in FIG. 3, the rotating stator 31 and the second stator 25
The windings 22 and 23 each having a star connection are connected in series. That is, the terminals A, B, and C of the winding 22 of the rotary stator 31 are connected to the commercial three-phase power supply A, B, and C, and the terminals a, b, and c of the winding 22 are connected to the windings of the second stator 25. line 23
terminal A of the winding 23.

b and c are connected by short-circuiting them.

Next, FIG.
This will be explained with reference to FIG.

Since the windings 22 and 23 are connected in series, current flows between the windings 22 and 23 from the commercial 3-phase power supply.
．． Even if there is a difference in the 4'3 iU of each resistor of 23 or the capacitance of both stators 31.25, the distribution of the current flowing in each winding 22.23 is equal, regardless of this difference. Therefore, the magnitude of the current induced and flowing from each of the rotating stator 31 and the second stator 25 to the conductor 5 of the rotor 8 becomes equal, so that the rotating stator 31... Both stators 31 and 25
The force that causes the magnitude of the current flowing from each of the conductors 5 of the rotor 8 to be equal is generated, and the current of the vector component due to the phase difference in voltage between both stators 31 and 25 is Due to the synergistic effect of the force that inevitably flows through the resistive material "..." which connects each of the plurality of conductors 5..., the slippage shown in Fig. 1 occurs. It is possible to improve efficiency in terms of torque characteristics and output a large l-ruque in each speed range, and even when a load is connected, it is easy to start each speed range, so it is easy to start the load. It can be used for smooth startup or high output depending on the characteristics, and can be optimally used for power sources that frequently start and stop.As mentioned above, the rotor 8 The rotational speed of the rotor 8 can be changed arbitrarily only by controlling the phase shift using the rotary stator 31 and increasing or decreasing the current flowing through the conductors 5 of the rotor 8. .

Note that the rotating stator 31 has windings 22 and 23 connected in series.
and the second stator 25 to the conductor 5 of the rotor 8, respectively.
・For the magnitude of the current flowing in ・, multiple conductors 5...
The ratio of the current flowing in %G between them through the resistive material r is determined by Pθ (P = number of pole pairs, θ = (The above ratio is the maximum when Pθ = π and becomes zero when Pθ = 0.) If Pθ is constant, the secondary insertion resistance of the general wound induction electric machine is constant. The slip and torque characteristics will be the same as in the case of This has the same effect as reducing the secondary insertion resistance of the motor. And when the rated current flows through both stators 31.25,
Even if the phase difference θ is arbitrarily changed, depending on the selection of the slip value and the design of the resistance value of the connecting material, it is possible to make the rated current and rated torque characteristics of the maximum speed work almost equally in each shift range. can.

In addition, the windings 22.2 of the rotary stator 31 and the second stator 25
3 are connected in series, if a connecting material is provided between the conductors 5 and there is no short circuit, almost no current will flow through the rotor conductors 5 when there is a phase difference. It becomes difficult.

Embodiments 1.2.3 of the rotor for the induction motor configured as described above will be described below with reference to FIGS. 1, 5, 6, 7, and 8.

First, the rotor cores 2 and 3 are generally made of laminated silicon steel plates or electromagnetic steel plates, but to explain in more detail,
The rotor cores 2 and 3 are formed by polymerizing and bonding a plurality of silicon steel plates, both sides of which are coated with phosphoric acid, to form an integral rotor core. A plurality of conductor insertion holes are bored in this silicon g4 root.

The rotor core 2.3, which is polymerized and bonded as described above, is provided with a notch on one end to prevent removal during casting and a stop on the other side to prevent removal during caulking, and the outer periphery is treated with insulation such as alumite. A hollow or solid conductor 5 is installed, and the conductor 5 is caulked on the short-circuit ring side to prevent aluminum from flowing into the gap between the conductor 5 and the conductor insertion hole during casting and causing poor insulation.
The conductor 5 is fixed to the rotor core. The short circuit rings 6, 7 on the notched side and the end portion 51 on the other side are formed by casting aluminum by a so-called aluminum die casting method, and a plurality of conductors 5, short circuit rings 6, 7, and further conductor 55 The rotor portions 2A, 3 are fused together with the end portion 51 for fitting the
A is integrally formed. (Fig. 6) Example - Hollow end with a notch to prevent removal during casting and an end 51 for bottoming the conductor 55 on the other side, and an insulating treatment such as anodized aluminum on the outer periphery. Alternatively, install a solid conductor 5, caulk the conductor 5 on the short-circuit ring side, and close the gap between the conductor 5 and the conductor insertion hole during casting so that aluminum does not flow into the gap and cause insulation defects, and connect the conductor 5 to the rotor core. stick. Short-circuit rings 6 and 7 are filled with aluminum on the notched side and formed by a so-called aluminum die-casting method, and the plurality of conductors 5 and short-circuit rings 6 and 7 are fused and the rotor parts 2A and 3A are integrally formed. is formed. (Fig. 7) Furthermore, the outer periphery of the conductor 5 is insulated with a hard insulating material that can withstand high temperatures, such as alumite, before being installed in the rotor core. This prevents the insulation of No. 5 from being destroyed, and also prevents the insulation material from changing or peeling off at high temperatures during casting or during low-speed rotation and high-torque generation of variable speed induction motors.

Furthermore, due to the characteristics of an induction motor, the conductor 5 may be skewed, but the conductor insertion hole of the rotor core is bonded in advance in a skewed state, and the conductor 5 formed in the same shape is attached to the rotor core 2°3. It can also be installed.

Further, in this embodiment, the short-circuit ring 6.7 was formed by casting aluminum, but the short-circuit ring 6.7 was formed separately from aluminum, the conductor 5 was installed in the rotor cores 2 and 3, and the short-circuit ring 6.7 was formed in advance.
, 7 are provided with insertion holes corresponding to the conductors.
It is also easy to swage the short-circuit ring and the short-circuit ring together and then weld them together. In other words, as Example (2), the outer periphery of the conductor 5 of Example (2) is insulated with alumite or the like, and the rotor core 2,
3, and short circuit rings 6 and 7 are installed on the side different from the end 51, and the conductor 5, rotor cores 2 and 3, and short circuit rings 6 and 7 are integrally caulked.The caulked parts of C1 are welded. By doing so, the rotor part 2A can be made in one piece without casting aluminum.

3A is completed. (FIG. 8) Here, the end portion 51 formed by casting or pre-formed on the conductor 5 is arranged so that the plurality of ends 51 are arranged at 19tll behind the plurality of conductors 5 installed in the plurality of conductor insertion holes. One end portion 51 is formed in that portion. However, one end portion 51 may be formed for each conductor 5.

Between the cast rotor cores 2 and 3, the end portion 51 formed on the rotor core 2.3 and the conductor 55 are fitted, and the conductor 55 is formed in a continuous manner, so that the rotor 8 form.

The conductor 55 described herein is made of copper, steel, stainless steel, copper-nickel alloy, iron, or the like.

Further, the conductor 55 fitted in the rotor 8 in a continuous manner is short-circuited via the strip-shaped resistance material r, and the resistance material r is connected to the rotor core 2.
, 3, a portion of the resistive material r protrudes to the outer periphery of the rotor between the conductors 55 fitted in a continuous manner to the end portions 51 of 3, forming a U-shape on the outer periphery of the rotor, and is fixed to the conductor 55 by welding. be. The welding mentioned here includes brazing. Also, the protruding U-shape mentioned here is
For example, the conductor 55a circumscribes the rotor inner part of the outer periphery, protrudes to the rotor outer periphery, turns back on an arbitrary extension, and again circumscribes the rotor inner part of the outer periphery of the next conductor 55b adjacent to the conductor 55a, Also, the protrusion on the outer circumference of the rotor (
In the bent shape, each of the resistive materials r is welded to the conductor 55 at the contact surface or point of contact between the conductor 55 and the resistive material r.

In addition to the embodiments, the resistance material r may have various shapes such as a zigzag shape or a meandering shape at the outer peripheral portion.

By the way, the resistance material r can be formed by forming a wide plate into the above shape, or by forming a plate into the shape of a band, and various sizes can be formed depending on the material of the resistance material r, that is, depending on the resistance value. becomes.

Here, a method for integrally forming the rotor configured as described above will be explained with reference to FIGS. 9, 10, and 11.

A central shaft 84 is inserted into a jig stand 80 provided with a press-fitting device 85, and a jig side plate 81, rotor cores 2 and 3 integrally formed by die-casting aluminum, and the rotor cores 2 and 3 are mounted in communication with the central shaft. The conductor 55 to be installed, the resistor material r, and the jig side plate 82 are inserted.

The jig side plates 81 and 82 are provided with a plurality of holes for fixing jig rods 83 which will be provided later to fix the resistance material r.

Next, a jig stand 8 is used to integrally form the coarse rotor 8.
The conductor 55 is press-fitted into the end portions 51 of the rotor cores 2 and 3 by a press-fitting device 85 provided on the upper part of the rotor core. (FIG. 11) Although this embodiment shows a method of press-fitting the conductor 55 into the end 51, it is also possible to press-fit the end 51 into the conductor 55.

(FIG. 12) By the way, before inserting the jig table, an oil compound of a conductive material is applied to one or both of the fitting portions of the conductor 55 and the end portion 51. This oil compound fills the gaps that occur on the fitting surfaces, reducing contact resistance, etc., and making the plurality of fitting surfaces equivalent.

Next, in order to fix the resistor material r that was inserted first here, we made the R
A plurality of jig rods 83 are fixed to the jig side plates 81 and 82 by passing the jig rods 83 through the rotor and spreading the resistance material r around the outer circumference of the rotor.

The jig rod 83 and the resistance material r fixed by the jig side plates 81 and 82 are welded while being connected and short-circuited to the conductor 55. The welding is general welding and includes brazing with a torch 85 or the like.

By the way, in the above embodiment, between the rotor cores 2 and 3,
The space surrounded by the conductor 55 may be either a space or a non-magnetic material. From the above, a rotor part in which a rotating core is cast and a rotor conductor, a short-circuit ring on one side, and an end opposite to the rotor conductor on the other side are integrally formed is formed at the end of the rotor part. Mating with multiple separate conductors.

A monolithic rotor with multiple rotor cores can now be easily formed using the simplest process of welding.

〔Effect of the invention〕

The structure of the rotor and the method of integrally forming the rotor described above include connecting each of a plurality of conductors installed in each of a plurality of rotor cores in a continuous manner to form an integral rotor. This is for a rotor that is integrally formed by short-circuiting the plurality of conductors through a resistive material, and provides a phase shift in the rotating magnetic field between the two stators to diversify the torque. 31. Regarding the production of a variable speed or improved startability type induction motor, it has been possible to provide a method for producing the rotor, which is low cost, highly efficient, and has high strength.

From this, variable speed induction motor 1 according to the rotor of the present invention
The machine was able to obtain high torque over a wide range of gear changes and a wide range of speeds.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a variable speed induction motor according to the present invention, FIG. 2 is a front sectional view of FIG. 1, FIG. 3 is a winding connection diagram, and FIG.
The figure shows the relationship between speed and torque when each of a plurality of rotor conductors is short-circuited with a resistive material and the windings wound around the stator are connected in series. A
FIG. 6 is a partial cross-sectional view of the rotor portion of the first embodiment, FIG. 7 is a partial cross-sectional view of the rotor portion of the second embodiment, and FIG. 8 is a partial cross-sectional view of the rotor portion of the second embodiment. FIG. 9 is a diagram of an embodiment in which the rotor is integrally formed, FIG. 10 is a welding of the rotor formed inside the body and the resistance material r, and FIG. 11 is a diagram of the rotor conductor. FIG. 12 is a detailed view of a fitting portion of a conductor separate from the rotor conductor, and FIG. 12 is a diagram of an embodiment different from FIG. 11. 1... Variable speed induction motor, 2, 3... Rotor core,
2A, 3A... Rotor part, 4... Rotor shaft, 5...
...Rotor conductor, 6,7...Short ring, 8...Rotor, 10.11...Both sides, 12...Tsutori shavings, 13.
... Cooling body, 14 ... Machine frame, 15.16 ... Bearing plate, 17 ... Bolt, 19.20 ... Cooling impeller, 21 ... Bearing, 22.23 ...・Winding wire, 24...
Pass 1! I11.25... Second stator, 26... Sliding bearing, 28... Stop ring, two... Drive device, 30... Rotating mechanism, 31... Rotating stator, 32
... Ventilation barrel, 35... Small motor, 36... Drive gear, 37... Opening, 38... So1.・Noid, 39...Exhaust port, 40...Ventilation port, 51...
Q; i; part, 52-m closing plate, 55.55a, 55b
, deceased) 5c, 55d... conductor, 66... space part,
67... Ventilation barrel, 68... Ventilation port, 69... Ventilation outlet, 70... Ventilation..., 71... Windmill, 72... Motor 73... Ventilation device, 74A... Air intake port, 7
4B...Exhaust port, 80...Jig stand, 81...Jig side plate, 82...Night [! Side plate, 83...Jig rod, 8
4... Central axis, 85... Torch, r... Resistance material,
S...Insulation sample.

Claims (8)

[Claims] (1) A conductor insulated with a hollow or solid shaft is installed in each slot of two rotor cores each having a plurality of slots, and the conductor is connected to both ends or one side of the rotor core. After crimping, aluminum is cast into each of the rotor cores, and a short-circuit ring is formed on one side of the rotor core, or an end of the conductor is formed on the other side, so that the rotor core and the conductor are connected to the short-circuit ring and the ends. The plurality of conductors are connected to the another conductor by fitting a conductor different from the conductor to the end between the ends of the two rotor parts. A rotor for an induction motor, characterized in that the separate conductors are connected in a continuous manner to form an integral squirrel cage rotor, and a connecting member is interposed between the separate conductors to short-circuit the separate conductors. Production method. (2) The rotor and its manufacturing method according to claim (1), wherein the conductor installed in the rotor core is a formed conductor whose end portion is integrally formed with the conductor. (3) The rotor and its manufacturing method according to any one of claims (1) and (2), wherein the formed conductor has a cutout at the other end different from the end. (4) Claims (1) to (4), wherein the insulation of the conductor installed in the rotor core is insulated by an oxide film, so-called alumite treatment, such as anodic oxidation treatment or chemical coating treatment.
3) The manufacturing method described. (5) The rotor and its manufacturing method according to any one of claims (1) to (4), wherein the conductor installed in the rotor core is made of aluminum as a base material. (6) The rotor and its manufacturing method according to any one of claims (1) to (5), wherein the aluminum forming the rotor portion is cast by a die-casting method. (7) The rotor and its manufacturing method according to any one of claims (1) to (6), wherein the connecting material to be welded to the conductor is made of copper-nickel alloy, nickel-chromium alloy, iron-chromium alloy, or stainless steel. (8) The rotor and its manufacturing method according to any one of claims (1) to (7), wherein the separate conductors are made of copper, steel, stainless steel, copper-nickel alloy, or iron.