APPARATUS FOR MEASURING BACKLASH IN SPECIMEN GEAR

• US 20140290084A1
• Filed: 04/02/2013
• Published: 10/02/2014
• Est. Priority Date: 04/02/2013
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Revach, Sam S.
• Granted Patent: US 9,109,975 B2
• Time in Patent Office: Days
• US Class Current: 33/701
• CPC Class Codes: G01B 21/02 for measuring length, width, or thickness G01B21/10 takes precedence
• CPC Class Codes: G01M 13/021 Gearings

Abstract

An apparatus for measuring a backlash in a specimen gear is provided. The apparatus includes a test gear mounted on a forward portion of a spindle, the test gear is configured to mesh with the specimen gear and form an electrical circuit upon contact with the specimen gear. An encoder is rotatably connected to the spindle and configured to output a rotation angle of the spindle. An interrupt unit is configured to detect an opening and closing of the electrical circuit and generate one or more interrupt signals based on the opening and the closing of the electrical circuit. A measuring unit is operatively coupled to the encoder and the interrupt unit, the measuring unit is configured to start measurement, and stop measurement of backlash based on the interrupt signal.

Claims

1. An apparatus for measuring backlash in a specimen gear, the apparatus including:

a test gear mounted on a forward portion of a spindle, the test gear configured to mesh with the specimen gear and form an electrical circuit upon contact with the specimen gear;

an encoder rotatably connected to the spindle and configured to output a rotation angle of the spindle;

an interrupt unit configured to detect an opening and closing of the electrical circuit and generate one or more interrupt signals based on the opening and the closing of the electrical circuit; and

a measuring unit operatively coupled to the encoder and the interrupt unit, the measuring unit configured to start measurement, and stop measurement of backlash based on the interrupt signal.

2. The apparatus of claim 1 further including:

a cradle including at least an upper section, and a lower section;

a body clamped between the upper and lower sections, the body defining a cavity therethrough; and

a sleeve disposed within the cavity, the sleeve configured to slideably receive the spindle.

3. The apparatus of claim 1 further including a handle rigidly connected at a rearward portion of the spindle, the handle configured to operatively rotate the spindle and the test gear.

4. The apparatus of claim 1 further including a pair of centering elements slideably mounted on the spindle and disposed on either side of the test gear, the centering elements configured to dispose the test gear substantially parallel to the specimen gear.

5. The apparatus of claim 1 further including a flange removably mounted on the spindle, the flange configured to attach the apparatus to an engine body.

6. The apparatus of claim 2, wherein the body, and the spindle are of an electrically conductive material, wherein the sleeve is of an electrically non-conductive material.

7. The apparatus of claim 3, wherein the handle includes an electrical port, the electrical port configured to dispose the spindle in electrical communication with an electrical energy source.

8. The apparatus of claim 1, wherein the encoder is one of an optical encoder, and an electrical resolver.

9. The apparatus of claim 1, wherein the measuring unit is further configured to set an absolute reference value of backlash based on the interrupt signal indicative of an existing closed electrical circuit.

10. The apparatus of claim 1, wherein the measuring unit is configured to start measurement of backlash based on the interrupt signal indicative of opening of the electrical circuit.

11. The apparatus of claim 1, wherein the measuring unit is configured to stop measurement of backlash based on the interrupt signal indicative of closing of the electrical circuit.

12. The apparatus of claim 1, wherein the interrupt unit and the measuring unit reside on a machine readable medium having a computer program product.

13. The apparatus of claim 13 further including an assist unit configured to display operating instructions relating to rotation of the test gear with respect to the specimen gear.

14. A method of measuring backlash in a ring gear of an engine, the method comprising:

meshing a test gear with the ring gear such that the test gear is configured to form an electrical circuit upon contact with the ring gear;

rotating the test gear with respect to the ring gear such that test gear loses contact with a tooth on the ring gear and opens the electrical circuit;

starting measurement of backlash upon opening of the electrical circuit;

rotating the test gear with respect to the ring gear such that test gear contacts an adjacent tooth of the ring gear and closes the electrical circuit; and

stopping measurement of backlash upon closing of the electrical circuit.

15. The method of claim 14 further including generating an interrupt signal based on the opening and the closing of the electrical circuit.

16. The method of claim 15 further including starting or stopping measurement of backlash based on the interrupt signal.

17. The method of claim 15 further including setting an absolute reference value of backlash based an interrupt signal indicative of opening of the electrical circuit.

18. The method of claim 15, wherein measurement of backlash is started based on the interrupt signal indicative of opening of the electrical circuit.

19. The method of claim 15, wherein measurement of backlash is stopped based on the interrupt signal indicative of closing of the electrical circuit.