Granted Patent B1

US 8,687,307 · App. 12/949,680 · Granted Apr 1, 2014

Abstract

Claims (78)

1. A disk drive comprising:

a head disk assembly (HDA) filled with a gas, the HDA comprising:

a disk;

a head actuated over the disk;

an electrical heating element; and

control circuitry operable to:

measure a pressure inside the HDA;

heat the electrical heating element for a first heating time;

measure a rate of temperature change of the electrical heating element; and

detect the gas leaking from the HDA in response to the pressure and the rate of temperature change by:

measuring a starting temperature (TEMPs) of the electrical heating element before heating the heating element;

measuring an ending temperature (TEMPe) of the electrical heating element after the first heating time;

determining a temperature threshold in response to TEMPs and TEMPe;

measuring a cooling time required for the temperature of the electrical heating element to cool to the temperature threshold; and

detecting the gas leaking from the HDA in response to the cooling time.

2. The disk drive as recited in claim 1 , wherein the rate of temperature change is a rate of cooling.

3. The disk drive as recited in claim 2 , wherein the control circuitry is further operable to:

measure an ending temperature (TEMPe) of the electrical heating element after the first heating time;

wait for a predetermined cooling time after the first heating time;

measure a cooled temperature (TEMPc) of the electrical heating element after the cooling time; and

detect the gas leaking from the HDA in response to the TEMPe and the TEMPc.

4. The disk drive as recited in claim 1 , wherein the rate of temperature change is a rate of heating.

5. The disk drive as recited in claim 4 , wherein the control circuitry is further operable to:

measure a first temperature (TEMP 1 ) of the electrical heating element after the first heating time;

heat the electrical heating element for a second heating time;

measure a second temperature (TEMP 2 ) of the electrical heating element after the second heating time; and

detect the gas leaking from the HDA in response to the TEMP 1 and the TEMP 2 .

6. The disk drive as recited in claim 1 , wherein the electrical heating element comprises a thermistor.

7. The disk drive as recited in claim 1 , wherein the electrical heating element comprises a diode.

8. The disk drive as recited in claim 1 , further comprising a temperature sensor located proximate the electrical heating element.

9. A method of operating a disk drive comprising a head disk assembly (HDA) filled with a gas, the HDA comprising a head actuated over a disk and an electrical heating element, the method comprising:

measuring a pressure inside the HDA;

heating the electrical heating element for a first heating time;

measuring a rate of temperature change of the electrical heating element; and

detecting the gas leaking from the HDA in response to the pressure and the rate of temperature change by:

measuring a starting temperature (TEMPs) of the electrical heating element before heating the heating element;

measuring an ending temperature (TEMPe) of the electrical heating element after the first heating time;

determining a temperature threshold in response to TEMPs and TEMPe;

measuring a cooling time required for the temperature of the electrical heating element to cool to the temperature threshold; and

detecting the gas leaking from the HDA in response to the cooling time.

10. The method as recited in claim 9 , wherein the rate of temperature change is a rate of cooling.

11. The method as recited in claim 10 , further comprising:

measuring an ending temperature (TEMPe) of the electrical heating element after the first heating time;

waiting for a predetermined cooling time after the first heating time;

measuring a cooled temperature (TEMPc) of the electrical heating element after the cooling time; and

detecting the gas leaking from the HDA in response to the TEMPe and the TEMPc.

12. The method as recited in claim 9 , wherein the rate of temperature change is a rate of heating.

13. The method as recited in claim 12 , further comprising:

measuring a first temperature (TEMP 1 ) of the electrical heating element after the first heating time;

heating the electrical heating element for a second heating time;

measuring a second temperature (TEMP 2 ) of the electrical heating element after the second heating time; and

detecting the gas leaking from the HDA in response to the TEMP 1 and the TEMP 2 .

14. The method as recited in claim 9 , wherein the electrical heating element comprises a thermistor.

15. The method as recited in claim 9 , wherein the electrical heating element comprises a diode.

16. The method as recited in claim 9 , further comprising measuring a temperature proximate the electrical heating element.

17. A disk drive comprising:

a head disk assembly (HDA) filled with a gas, the HDA comprising:

a disk;

a head actuated over the disk;

an electrical heating element; and

control circuitry operable to:

measure a pressure inside the HDA;

heat the electrical heating element for a first heating time;

measure a rate of temperature change of the electrical heating element; and

detect the gas leaking from the HDA in response to the pressure and the rate of temperature change by:

measuring a first temperature (TEMP 1 ) of the electrical heating element after the first heating time;

heating the electrical heating element for a second heating time;

measuring a second temperature (TEMP 2 ) of the electrical heating element after the second heating time; and

detecting the gas leaking from the HDA in response to the TEMP 1 and the TEMP 2 .

18. A method of operating a disk drive comprising a head disk assembly (HDA) filled with a gas, the HDA comprising a head actuated over a disk and an electrical heating element, the method comprising:

measuring a pressure inside the HDA;

heating the electrical heating element for a first heating time;

measuring a rate of temperature change of the electrical heating element; and

detecting the gas leaking from the HDA in response to the pressure and the rate of temperature change by:

measuring a first temperature (TEMP 1 ) of the electrical heating element after the first heating time;

heating the electrical heating element for a second heating time;

measuring a second temperature (TEMP 2 ) of the electrical heating element after the second heating time; and

detecting the gas leaking from the HDA in response to the TEMP 1 and the TEMP 2 .

Assignments (7)