Automatic flow grind system and method

• US 5,333,112 A
• Filed: 03/25/1993
• Issued: 07/26/1994
• Est. Priority Date: 03/25/1993
• Status: Expired due to Term

• Current Assignee: AAI Corporation (Textron Inc)
• Original Assignee: AAI/ACL Technologies, Inc.
• Inventors: Bybee, Jimmy L.
• Primary Examiner(s): Smith, Jerry
• Assistant Examiner(s): Garland, Steven R.
• Application Number:
  US08/037,032
• Time in Patent Office: 488 Days
• Field of Search: 364/474.06, 364/474.11, 364/474.17, 364/509, 364/510, 364/550, 51/165.71, 51/165.74
• US Class Current: 700/164
• CPC Class Codes: B24B 49/00 Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation B24B33/06, B24B37/005 take precedence; if applicable to other machine tools, B23Q15/00 - B23Q17/00 take precedence
• CPC Class Codes: G05B 19/401 characterised by control arrangements for measuring, e.g. calibration and initialisation, measuring workpiece for machining purposes G05B19/19 takes precedence
• CPC Class Codes: G05B 2219/45161 Grinding machine
• CPC Class Codes: G05B 2219/50068 Test valve, object, store parameters, machine object to get wanted performance

Abstract

A system for the measurement of servo-valve "spool and sleeve sets" using automatic flow and pressure gain, plus displacement measurements. The system precisely grinds spool land edges so as to exactly match these edges with the sleeve slots or holes in order to meet the required overlap/underlap and performance requirements of the servo-valve. All operations are controlled by a computer in accordance with servo-valve performance parameters that are held in memory corresponding to the "spool and sleeve set" part number.

Claims

1. An automated system for machining servo-valves, comprising:

(a) a computer-controlled measurement console, comprising means for testing a particular servo-valve comprising a spool and sleeve set using automatic flow, pressure, and displacement measurements, means for generating data for use in flow-gain and removal calculations to determine flow and pressure gain performance characteristics for the servo-valve, means for performing the flow-gain and removal calculations, and means for storing results thereof in a memory corresponding to a unique identifier for the spool and sleeve set; and

(b) a computer-controlled grind console, coupled to the computer-controlled measurement console, comprising means for machining the particular servo-valve according to the results of the flow-gain and removal calculations, further comprising contact gaging means for measuring a land width and a gap between the land edges of the spool, and means for precisely grinding the spool'"'"'s land edges so as to exactly match these edges with the sleeve slots to meet overlap/underlap requirements and performance requirements of the servo-valve, wherein the results of the flow-gain and removal calculations, the overlap/underlap requirements, and the performance requirements of the servo-valve are stored in a memory corresponding to the unique identifier for the spool and sleeve set.

2. The system of claim 1, wherein the computer-controlled measurement console further comprises means for hydraulically measuring a relationship between metering edges of the spool and the slots in the sleeve.

3. The system of claim 1, wherein the measurement console further comprises means for testing the spool and sleeve set by applying hydraulic flow and pressure as the spool is being controlled by a linear actuator, so that flows and pressures are accurately measured and recorded by the computer.

4. The system of claim 1, wherein the means for performing the flow-gain and removal calculations further comprise means for performing multiple-land flow-gain and edge removal calculations on the spool and sleeve set.

5. The system of claim 1, wherein the means for performing the flow-gain and removal calculations further comprise means for calculating how much material must be ground from each metering edge to produce a desired mechanical synchronization for the servo-valve.

6. The system of claim 1, wherein the means for performing the flow-gain and removal calculations further comprises means for analyzing flow and position data to find slopes and intercepts for all lands of the spool.

7. The system of claim 6, wherein the means for analyzing further comprises means for using intercept values to find an average intercept as a common reference position.

8. The system of claim 6, wherein the means for analyzing further comprises means for using slope values to evaluate the gain performance for acceptability.

9. The system of claim 6, wherein the means for analyzing further comprises means for using leakage information to determine a fundamental acceptability of the servo-valve.

10. The system of claim 1, wherein the means for precisely grinding comprises means for proceeding to each edge of the spool in sequence and means for removing a prescribed amount of material from each edge of the spool according to the removal calculations performed by the measurement console.

11. The system of claim 1, wherein the grind console further comprises a unit under test (UUT) definitions database organized by UUT name, and a material removal database organized by UUT name and UUT serial number, wherein the UUT definitions database and the material removal database are used by the grind console to control the grinding operations for the spool and sleeve set.

12. The system of claim 11, wherein a UUT definition screen provides access to the UUT definition database, and an automatic mode screen provides access to the material removal database.

13. The system of claim 12, wherein the UUT definition screen is used to specify nominal UUT dimensions.

14. The system of claim 12, wherein the automatic mode screen is used to specify how much material to remove from each edge of the spool.