# US 6,295,863 B1 · Method and apparatus for determining seal failure in a ball joint

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 6,295,863 B1
- Document ID: US6295863B1
- Status: Granted
- Kind: B1
- Application number: 09/625,590
- Filed: 2000-07-26
- Granted: 2001-10-02
- Earliest claimed: 2000-07-26
- Assignees: Ford Global Technologies, LLC
- Inventors: John Matthew Ginder; William McMurray Stewart
- Web page: https://patentgrep.com/patent/US6295863B1

## CPC

- G01M 3/04: by detecting the presence of fluid at the leakage point
- F16C 11/0671: {allowing operative relative movement of joint parts due to flexing of the sealing means}
- F16C 11/068: {Special features relating to lubrication}
- F16C 17/24: with devices affected by abnormal or undesired positions, e.g. for preventing overheating, for safety
- F16C 33/102: {with grease as lubricant}
- G01M 3/16: using electric detection means ({G01M3/045,} G01M3/06, G01M3/12, G01M3/20, G01M3/24, G01M3/26 take precedence)
- F16C 11/0619: {the female part comprising a blind socket receiving the male part}
- Y10T 403/20: with indicator or inspection means
- G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A method of determining seal failure is implemented in a ball joint including a stud having a ball embedded in grease within a sealed socket assembly. A dielectric characteristic of the grease is measured to determined if the sealed socket assembly has failed based upon a substantial variation of the measured dielectric characteristic from a predetermined value.

## Claims

### Claim 1

A method of determining seal failure in a ball joint including a stud having a ball embedded in grease within a sealed socket assembly, the method comprising:
measuring a dielectric characteristic of the grease;
determining that the sealed socket assembly has failed if the measured dielectric characteristic substantially varies from a predetermined value;
wherein said step of measuring a dielectric characteristic comprises measuring capacitance of the grease; and
wherein said step of measuring capacitance of the grease comprises connecting a capacitance gauge to the stud and to the socket assembly.

### Claim 2 (depends on 1)

The method of claim 1, wherein said step of measuring a dielectric characteristic comprises measuring resistance of the grease.

### Claim 3 (depends on 1)

The method of claim 1, wherein said connecting to the socket assembly comprises connecting to a lower clamping ring which secures a rubber boot around the socket assembly.

### Claim 4 (depends on 1)

The method of claim 1, wherein said step of measuring a dielectric characteristic comprises monitoring the dielectric characteristic by periodically sensing for changes in the dielectric characteristic.

### Claim 5 (depends on 1)

The method of claim 1, wherein said determining step comprises sensing an increase in capacitance.

### Claim 6

A method of sensing water leakage into a ball joint including a stud having a ball embedded in grease within a sealed socket assembly, the method comprising:
measuring a dielectric characteristic of the grease;
determining that water has leaked into the ball joint if the measured dielectric characteristic substantially varies from a predetermined value;
wherein said step of measuring a dielectric characteristic comprises measuring capacitance of the grease; and
wherein said step of measuring capacitance of the grease comprises connecting a capacitance gauge to the stud and to the socket assembly.

### Claim 7 (depends on 6)

The method of claim 6, wherein said step of measuring a dielectric characteristic comprises measuring resistance of the grease.

### Claim 8 (depends on 6)

The method of claim 6, wherein said connecting to the socket assembly comprises connecting to a lower clamping ring which secures a rubber boot around the socket assembly.

### Claim 9 (depends on 6)

The method of claim 6, wherein said step of measuring a dielectric characteristic comprises monitoring the dielectric characteristic by periodically sensing for changes in the dielectric characteristic.

### Claim 10 (depends on 6)

The method of claim 6, wherein said determining step comprises sensing an increase in capacitance.

### Claim 11

A ball joint assembly comprising:
a stud having a ball at an end thereof;
a socket having grease therein, within which the ball is embedded;
a rubber boot sealing the socket; and
a capacitance gauge operatively connected across the grease for determining capacitance changes of the grease indicative of water leakage into the socket;
wherein the capacitance gauge is connected to the stud and to a clamping ring which secures the rubber boot over the socket.