ELECTRIC LINEAR ACTUATOR ASSEMBLY AND METHOD OF ASSEMBLY

• US 20140159768A1
• Filed: 03/15/2013
• Published: 06/12/2014
• Est. Priority Date: 05/20/2012
• Status: Active Grant

• Current Assignee: MTS Systems Corporation (Illinois Tool Works Inc.)
• Original Assignee: MTS Systems Corporation (Illinois Tool Works Inc.)
• Inventors: Schulz, Bradley D.
• Granted Patent: US 9,797,943 B2
• Time in Patent Office: Days
• US Class Current: 324/765.01
• CPC Class Codes: G01R 31/28 Testing of electronic circuits, e.g. by signal tracer EMC, EMP or similar testing of electronic circuits G01R31/002; testing for short-circuits, discontinuities, leakage or incorrect line connection G01R31/50; checking computers or computer components G06F11/00; checking static stores for correct operation G11C29/00 ; testing receivers or transmitters of transmission systems H04B17/00
• CPC Class Codes: H02K 15/14 Casings; Enclosures; Supports
• CPC Class Codes: H02K 15/16 Centering rotors within the stator; Balancing rotors
• CPC Class Codes: H02K 41/03 Synchronous motors; Motors moving step by step; Reluctance motors H02K41/035 takes precedence
• CPC Class Codes: H02K 5/00 Casings; Enclosures; Supports
• CPC Class Codes: Y10T 29/49009 Dynamoelectric machine

Abstract

A method of constructing an electric linear displacement motor for use in a testing device includes providing a stator having as stator housing with internal coils and a through bore extending from a first end of the stator housing to the second end of the housing. First and second end supports are connected to the first and second ends of the stator housing. An armature having magnets retained therein is inserted into the stator housing such of the armature is supported by the first end support and the second end support. A plurality of set screws are inserted into threaded openings proximate both the first end and the second end of the housing. The set screws then support and retain the armature such that there is an annular gap between the armature and the coils.

Claims

1. A method of constructing an electric linear displacement motor for use in a testing device, the method comprising:

providing a stator having as stator housing with internal coils and a through bore extending from a first end of the stator housing to the second end of the housing;

connection a first end support to the first end of the stator housing and a second end support to the second end of the stator housing wherein the first and second end supports each have aligned through bores that align with the through bore in the stator housing;

inserting an armature having magnets retained therein from a first end to a second end through either the through bore in the first end support or the second end support and into the housing until either the first end or the second end of the armature is supported by the first end support and the other end of the armature is supported by the second end support such that an annular gap separates the armature and the coils; and

inserting a plurality of set screws into threaded openings proximate both the first end and the second end of the housing such that the set screws retain the armature and the first and second end supports provide no support to the armature.

2. The method of claim 1 and further comprising:

removing the first end support from the first end of the stator housing; and

removing the second end support for the second end of the stator housing.

3. The method of claim 2 and further comprising:

attaching a first bearing housing to the first end of the stator housing; and

attaching a second bearing housing to the second end of the stator housing.

4. The method of claim 3 and further comprising:

positioning a first bearing in the first bearing housing such that the first bearing engages and carries one end of the armature; and

positioning a second bearing in the second bearing housing such that the second bearing engages and carries another end of the armature.

5. The method of claim 4 and further comprising removing the plurality of set screws from proximate the first and second ends of the stator housing such that the armature free moves within the stator housing.

6. The method of claim 2 and further comprising:

attaching a first end portion to the first end of the armature; and

attaching a second end portion to the second end of the armature where the first and second end portions are attached to the armature prior to installing the bearing housing and the bearings.

7. The method of claim 6 and further comprising:

positioning the first bearings within the first bearing housings such that the first end portion engages and is carried by the first bearing; and

positioning the second bearings within the second bearing housings such that the second end portion engages and is carried by the second bearing.

8. The method of claim 6 and wherein the attaching of the first and second end portions to the first and second ends of the armatures is through threadable engagements.

9. An electric linear displacement motor for use in a testing apparatus, the electric linear displacement motor comprising:

a stator assembly comprising;

a stator housing having a first end and a second end and a through bore extending from the first end to the second end; and

a plurality of coils within the stator housing where each of the individual coils in the plurality of coils can be independent energized to create a desired electric field within the stator;

an armature assembly comprising;

an armature having a first end and a second end and wherein the armature includes a plurality of magnets along a length of the armature;

a first end portion coupled to the first end of the armature wherein the first end portion has a first selected length; and

a second end portion coupled to the second end of the armature wherein the second end portion has a second selected length;

a first bearing assembly attached to the first end of the stator housing, the first bearing assembly comprising;

a first bearing housing configured to be attached to the first end of the stator housing; and

a first bearing positioned within the first bearing housing and wherein the first end portion engages and is carried by the first bearing and wherein the armature does not contact the first bearing; and

a second bearing assembly attached to the second end of the stator housing, the second bearing assembly comprising;

a second bearing housing configured to be attached to the second end of the stator housing; and

a second bearing positioned within the second bearing housing and wherein the second end portion engages and is carried by the second bearing and wherein the armature does not contact the second bearing.

10. The electric linear displacement motor of claim 9 and wherein the armature comprises a cylindrical rod having a first diameter.

11. The electric linear displacement motor of claim 10 and wherein the first and second end portions both a second diameter substantially equal to the first diameter of the armature.

12. The electric linear displacement motor of claim 10 and wherein the first and second end portions both a second diameter greater than the first diameter of the armature.

13. The electric linear displacement motor of claim 9 and wherein the first and second end portions are of a different material than the armature.

14. The electric linear displacement motor of claim 9 and wherein both the first and second bearing assemblies are beyond a magnetic field generated when the coils of the stator are energized and interact with the magnets.

15. The electric linear displacement motor of claim 9 and further comprising a plurality of fins extending from the stator housing.

16. A testing apparatus comprising:

an electric linear displacement motor comprising;

a stator assembly comprising;

a stator housing having a first end and a second end and a through bore extending from the first end to the second end; and

a plurality of coils within the stator housing where each of the individual coils in the plurality of coils can be independent energized to create a desired electric field within the stator;

an armature assembly comprising;

an armature having a first end and a second end and wherein the armature includes a plurality of magnets along a length of the armature;

a first end portion coupled to the first end of the armature wherein the first end portion has a first selected length; and

a second end portion coupled to the second end of the armature wherein the second end portion has a second selected length;

a first bearing assembly attached to the first end of the stator housing, the first bearing assembly comprising;

a first bearing housing configured to be attached to the first end of the stator housing; and

a first bearing positioned within the first bearing housing and wherein the first end portion engages and is carried by the first bearing and wherein the armature does not contact the first bearing; and

a second bearing assembly attached to the second end of the stator housing, the second bearing assembly comprising;

a second bearing housing configured to be attached to the second end of the stator housing; and

a second bearing positioned within the second bearing housing and wherein the second end portion engages and is carried by the second bearing and wherein the armature does not contact the second bearing; and

a load cell coupled to the second end portion; and

a specimen holder coupled to the load cell.

17. The testing apparatus of claim 16 wherein the first and second end portions both a second diameter greater than a first diameter of the armature.

18. The testing apparatus of claim 16 wherein the first and second end portions are of a different material than the armature.

19. The testing apparatus of claim 16 and wherein both the first and second bearing assemblies are beyond a magnetic field generated when the coils of the stator are energized and interact with the magnets.

20. The testing apparatus of claim 16 and wherein the stator housing further comprises a plurality of fins extending from the stator housing.