# US 5,349,742 A · Method of making a secondary for use in induction motors

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- Number: US 5,349,742 A
- Document ID: US5349742A
- Status: Granted
- Kind: A
- Application number: 07/937,354
- Filed: 1992-08-27
- Granted: 1994-09-27
- Earliest claimed: 1991-08-29
- Assignees: BLUM GmbH
- Inventors: Eugen Nolle
- Web page: https://patentgrep.com/patent/US5349742A

## CPC

- H02K 41/025: Asynchronous motors
- H02K 15/023: Cage rotors
- H02K 17/18: having double-cage or multiple-cage rotors
- H02K 17/20: having deep-bar rotors
- Y10T 29/49012: Rotor
- Y10T 29/49073: by assembling coil and core
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The core of the secondary for use in a linear or other induction motor is a ladder-like stamping with two spaced apart rails and a number of bars extending between and having end portions of one piece with the rails. The bars of the cage can be inserted into the recesses of a core, and such recesses can be provided in one side or in two opposite sides of the core. Each recess can receive a single bar or the bars of two or more discrete cores. The bars can be confined in their recesses by slidable closures or by plugs of a hardened adhesive, a synthetic resin or an impregnating agent.

## Claims

### Claim 1

A method of making a secondary for use in an induction motor comprising the steps of:
(a) providing a core with at least one set of recesses;
(b) forming at least two substantially ladder-shaped cages, each said cage having two spaced apart rails and bars extending between, and of one piece with, the rails; and
(c) inserting the bars of each said cage into respective recesses of the core, so as to stack the bars in the recesses and at least partially fill the recesses with stacked bars.

### Claim 2 (depends on 1)

The method of claim 1, wherein said forming step comprises stamping at least one said cage from a blank.

### Claim 3 (depends on 1)

The method of claim 1, wherein said forming step includes making at least one said cage from a sheet-like blank of a material which is selected from the group consisting of copper and aluminum.

### Claim 4 (depends on 1)

The method of claim 1, wherein said step of providing recesses includes providing the core with grooves each having an open side and said inserting step includes introducing the bars into the grooves so that the bars are spaced apart from the open sides of the grooves, and further comprising the step of anchoring the bars in the respective grooves, including admitting a hardenable substance into the grooves at the open sides thereof.

### Claim 5 (depends on 4)

The method of claim 4, wherein said providing step further comprises providing each said groove with at least one lateral extension at the open side thereof, said anchoring step comprising admitting the hardenable substance in quantities such as to at least partially fill the extensions.

### Claim 6 (depends on 4)

The method of claim 4, wherein the hardenable substance is an adhesive.

### Claim 7 (depends on 4)

The method of claim 4, wherein the hardenable substance is a synthetic resin.

### Claim 8 (depends on 4)

The method of claim 4, wherein said hardenable substance contains an impregnating agent and magnetizable ingredients in the impregnating agent.

### Claim 9 (depends on 1)

The method of claim 1, wherein said step of providing recesses includes providing the core with grooves each having an open side and at least one lateral extension at the open side thereof, said inserting step comprising introducing the bars into the grooves so that the extensions of the grooves are located between the introduced bars and the respective open sides, and further comprising the step of confining the bars in the respective grooves including overlapping the introduced bars by closures having portions extending into the respective extensions.

### Claim 10 (depends on 1)

The method of claim 1, wherein said providing step comprises assembling a stack of superimposed laminations having cutouts which together constitute the recesses of the core.

### Claim 11 (depends on 1)

The method of claim 1, wherein said forming step includes forming the at least one cage with windows which alternate with the bars, said providing step comprising making the core of at least one lamination having sections which extend into the windows upon completion of said inserting step.

### Claim 12 (depends on 11)

The method of claim 11, wherein said providing step comprises making the core from a plurality of superimposed laminations having aligned sections extending into the windows upon completion of the inserting step.

### Claim 13 (depends on 12)

The method of claim 12, wherein portions of sections of at least one lamination project from the respective windows, and further comprising the step of bending the projecting portions of the sections of said at least one lamination to confine such sections in the respective windows.

### Claim 14 (depends on 13)

The method of claim 13, wherein the at least one lamination abuts a bar of the at least one cage.

### Claim 15 (depends on 11)

The method of claim 11, wherein said making step comprises providing a discrete strip-shaped lamination for each window of the at least one cage and folding each lamination into a package of neighboring layers having ends which extend from the respective window upon completion of said inserting step.

### Claim 16 (depends on 15)

The method of claim 15, wherein each window is disposed between two neighboring bars, and further comprising the step of bending each end of each inserted package against one of the neighboring bars.

### Claim 17 (depends on 1)

The method of claim 1, wherein said providing step comprises making a cylindrical core having a peripheral surface with the at least one set of recesses in the peripheral surface.

### Claim 18 (depends on 17)

The method of claim 17, wherein said inserting step comprises introducing each bar into a discrete recess and deforming the rails between the bars.

### Claim 19 (depends on 18)

The method of claim 18, wherein said inserting step further comprises flexing the rails at the peripheral surface into ring-shaped bodies.

### Claim 20 (depends on 1)

The method of claim 1, wherein each of said recesses has an open side and said inserting step includes introducing the bars into the recesses so that the bars are spaced apart from the open sides of the recesses, and further comprising the step of anchoring the bars in the respective recesses, including admitting a hardenable substance into the recesses at the open sides thereof.

### Claim 21 (depends on 20)

The method of claim 20, wherein said providing step further comprises providing each said recess with at least one lateral extension at the open side thereof, said anchoring step comprising admitting the hardenable substance in quantities so as to at least partially fill the extensions.

### Claim 22 (depends on 20)

The method of claim 20, wherein the hardenable substance is an adhesive.

### Claim 23 (depends on 20)

The method of claim 20, wherein the hardenable substance is a synthetic resin.

### Claim 24 (depends on 20)

The method of claim 20, wherein said hardenable substance contains an impregnating agent and magnetizable ingredients in the impregnating agent.

### Claim 25 (depends on 1)

The method of claim 1, wherein each of said recesses has an open side and at least one lateral extension at the open side thereof, said inserting step comprising introducing the bars into the recesses so that the at least one extension is located between the introduced bars and the respective open side, and further comprising the step of confining the bars in the respective recesses including overlapping the introduced bars by closures having portions extending into the respective extensions.

### Claim 26

A method of making a secondary for use in an induction motor, comprising the steps of:
(a) providing a plurality of discrete cores;
(b) forming at least one substantially ladder-shaped cage, each said cage having two spaced apart rails and bars extending between, and of one piece with the rails, and windows which alternate with said bars; and
(c) inserting the cores into respective windows of the at least one cage, each said core being formed of at least one package of neighboring layers having sections which extend into said windows upon completion of said insertion step, each of said cores at least partially filling a respective window.

### Claim 27 (depends on 26)

The method of claim 26, wherein said providing step comprises assembling a stack of superimposed laminations for each said core.

### Claim 28 (depends on 26)

The method of claim 26, wherein said providing step comprises making each of said cores from a plurality of superimposed layers having aligned sections extending into the windows upon completion of the inserting step.

### Claim 29 (depends on 26)

The method of claim 26, wherein said providing step comprises providing a discrete strip-shaped layer for each window of the at least one cage and folding each layer into a package of neighboring layers having ends which extend from the respective window upon completion of said inserting step.

### Claim 30

A method of making a secondary for use in an induction motor, comprising the steps of:
(a) forming at least one substantially ladder shaped cage, each said cage having two spaced apart rails and bars extending between, and of one piece with the rails, and windows which alternate with said bars; and
(b) inserting discrete cores at least partially into respective windows of the cage, each of said cores being formed of at least one package of neighboring layers having sections which extend into said window upon completion of said insertion step, each of said cores at least partially filling a respective window.

### Claim 31 (depends on 30)

The method of claim 30, wherein said forming step comprises stamping the at least one cage from a blank.

### Claim 32 (depends on 30)

The method of claim 30, wherein said forming step includes making the at least one cage from a sheet-like blank of a material which is selected from the group consisting of copper and aluminum.

### Claim 33 (depends on 30)

The method of claim 30, wherein portions of sections of at least one layer project from the respective windows, and further comprising the step of bending the projecting portions of the sections of said at least one layer to confine such sections in the respective windows.

### Claim 34 (depends on 33)

The method of claim 33, wherein the at least one layer abuts a bar of the at least one cage.

### Claim 35 (depends on 30)

The method of claim 30, wherein each window is disposed between two neighboring bars, and further comprising the step of bending each end of each inserted package against one of the neighboring bars.