Pressure sensor integrated into an electro-hydraulic control unit

• US 6,374,679 B1
• Filed: 12/27/1999
• Issued: 04/23/2002
• Est. Priority Date: 12/28/1998
• Status: Expired due to Term

• Current Assignee: Kelsey-Hayes Co. (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: Kelsey-Hayes Co. (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Baron, Thomas, Babala, Michael L., Bolitho, Marc, Gegalski, Helmut, Schliebe, Paul M.
• Primary Examiner(s): Fuller, Benjamin R.
• Assistant Examiner(s): ALLEN, ANDRE J
• Application Number:
  US09/473,236
• Time in Patent Office: 848 Days
• Field of Search: 737/15, 731/16, 737/17, 731/18, 731/19, 737/56
• US Class Current: 73/715
• CPC Class Codes: B60T 8/3675 integrated in modulator units
• CPC Class Codes: F15B 11/028 for controlling the actuating force F15B11/024 takes precedence
• CPC Class Codes: F15B 13/0803 Modular units
• CPC Class Codes: F15B 2013/004 Cartridge valves
• CPC Class Codes: F15B 2211/25 Pressure control functions
• CPC Class Codes: F15B 2211/50554 the pressure control means controlling a pressure downstream of the pressure control means, e.g. pressure reducing valve
• CPC Class Codes: F15B 2211/526 electrically or electronically
• CPC Class Codes: F15B 2211/6313 the pressure being a load pressure
• CPC Class Codes: F15B 2211/6346 representing a state of input means, e.g. joystick position
• CPC Class Codes: F15B 2211/6653 Pressure control
• CPC Class Codes: F15B 2211/7052 Single-acting output members
• CPC Class Codes: F15B 2211/857 Monitoring of fluid pressure systems
• CPC Class Codes: G01L 19/0007 Fluidic connecting means
• CPC Class Codes: G01L 19/003 using a detachable interface or adapter between the process medium and the pressure gauge
• CPC Class Codes: G01L 19/0084 to the outside of the housing other details about the housing see G01L19/14
• CPC Class Codes: G01L 19/0645 using isolation membranes, specially adapted for protection
• CPC Class Codes: G01L 19/14 Housings G01L19/0007, G01L19/0084, G01L19/0092, G01L19/04, G01L19/06 take precedence
• CPC Class Codes: G01L 19/142 Multiple part housings
• CPC Class Codes: G01L 19/147 Details about the mounting of the sensor to support or covering means
• CPC Class Codes: G01L 19/148 Details about the circuit board integration, e.g. integrated with the diaphragm surface or encapsulation
• CPC Class Codes: G01L 9/0051 : using variations in ohmic resistance
• CPC Class Codes: G01L 9/0072 : using variations in capacitance

Abstract

A pressure sensor is mounted integrally in a hydraulic valve body. The sensor has a base which extends into a bore formed in the valve body. The valve body bore is in communication with a pressurized hydraulic fluid. A first circumferential groove formed in the sensor base carries an O-ring which forms a seal between the sensor and the wall of the valve body bore. A second circumferential groove formed in the sensor base carries a spring ring which extends into a corresponding groove formed in the wall of the valve body groove. The spring ring cooperates with the sensor base and valve body bore grooves to retain the sensor in the valve body bore.

Claims

1. A pressure sensor for a hydraulic control system that includes a hydraulic valve body having a bore formed therein, said pressure sensor comprising:

a cylindrical base portion having a circumferential groove formed therein, said base portion having a diameter corresponding to the size of the bore formed in the hydraulic body such that the base portion is insertable inserted into the bore;

a ring of resilient material disposed within said circumferential groove, said resilient material adapted to form a seal between said base portion and a wall of the bore formed in the hydraulic valve body; and

a pressure sensing device mounted upon said base portion.

2. A sensor according to claim 1 wherein said circumferential groove is a first groove and said base portion has a second circumferential groove formed therein and further wherein the bore in the hydraulic valve body has a circular groove formed in the wall thereof that corresponds to said second circumferential groove formed in said sensor base portion, said second circumferential groove formed in said sensor base portion having a spring ring disposed therein, said spring ring cooperating with said complementary groove formed in said hydraulic valve body bore wall to retain said sensor base portion in said valve body bore.

3. A sensor according to claim 2 further including an axial electrical connector mounted upon said base portion.

4. A sensor according to claim 3 wherein said electrical connector includes a plurality of electrical connectors.

5. A sensor according to claim 3 wherein said sensor base portion has an axial bore formed therein and a diaphragm that extends across an end of said bore, said diaphragm carrying said pressure sensing device and further wherein said bore is adapted to receive pressurized hydraulic fluid.

6. A sensor according to claim 5 wherein the hydraulic valve body has a plurality of solenoid valves mounted thereon with the sensor being mounted in the hydraulic valve body adjacent to said plurality of solenoid valves and further wherein the sensor is enclosed by a removable housing, said housing forming a hermetic seal with said valve body, said housing also carrying solenoid coils for said solenoid valves.

7. A sensor according to claim 6 wherein said electrical connector is a male connector and said housing carries a female connector which cooperates with said male connector to form an electrical connection for said pressure sensing device.

8. A sensor according to claim 5 further including a cylindrical insert disposed within said axial bore formed in said sensor base portion, said insert having an axial bore formed therethrough.

9. A sensor according to claim 8 wherein said base portion has a stepped exterior shape and further wherein said valve body bore also is stepped with said valve body bore step cooperating with said sensor base portion step to define an insertion distance for the sensor base portion into said valve body bore.

10. A sensor according to claim 5 further including a signal conditioning circuit carried by said sensor base portion.

11. A sensor according to claim 10 wherein said signal conditioning circuit performs diagnostic tests upon said pressure sensing device and, upon detecting a non-operable pressure sensor, generates an error signal.

12. A sensor according to claim 11 wherein said diagnostic test is performed upon initial power up of the sensor.

13. A sensor according to claim 11 wherein said signal conditioning circuit is connected to a microprocessor included in a vehicle brake control system, said signal conditioning circuit being responsive to a signal from said microprocessor to transmit pressure data to said microprocessor.

14. A sensor according to claim 13 further including a temperature sensor, said signal conditioning circuit being operable to transmit temperature data to said microprocessor.

15. A sensor according to claim 14 wherein said data is transmitted with a pulse modulated wave with a frequency being a function of said temperature data and a duty cycle being a function of said pressure data.

16. A sensor according to claim 14 wherein said data is transmitted with a pulse modulated wave with a frequency being a function of said pressure data and a duty cycle being a function of said temperature data.

17. A sensor according to claim 1 wherein said circumferential groove is a first groove and said ring of resilient material is a first ring of resilient material and further wherein said sensor base portion has a second circumferential groove formed therein, said second circumferential groove having a second ring of resilient material disposed therein, said resilient material in said second ring also adapted to form a seal between said sensor base portion and the valve body bore, and further wherein the valve body has a fluid supply passageway formed therein which communicates with the valve body bore between said first and second resilient rings, said fluid supply passageway adapted to supply pressurized hydraulic fluid to said valve body bore whereby any axial pressures exerted upon the sensor are balanced.

18. A sensor according to claim 17 wherein said sensor base portion further includes a pressure sensing port formed therein between said rings of resilient material.

19. A pressure sensor according to claim 18 further including a third circumferential groove formed in said sensor base portion and further wherein the bore in the hydraulic valve body has a circular groove formed in the wall thereof that corresponds to said third circumferential groove formed in said sensor base portion, said third circumferential groove having a spring ring disposed therein, said spring ring adapted to cooperate with said complementary groove formed in said hydraulic valve body bore wall to retain said sensor in said valve body bore.

20. A pressure sensor according to claim 5 wherein the pressure sensor is included in a traction control system.

21. A pressure sensor according to claim 5 wherein the pressure sensor is included in a vehicle stability system.

22. A method for installing a pressure sensor into a hydraulic valve body comprising the steps of:

(a) providing a pressure sensor having a cylindrical base portion which carries a spring ring in a first circumferential groove formed therein and a ring of resilient material carried in a second circumferential groove formed therein;

(b) inserting the pressure sensor partially into a bore in a valve block for a hydraulic control system until the ring of resilient material forms a seal with a wall of the valve block bore;

(c) connecting the pressure sensor to pressure monitoring equipment;

(d) pressurizing the valve block bore;

(e) observing the monitoring equipment to confirm operation of the pressure sensor; and

(f) inserting the pressure sensor filly into the valve body bore upon obtaining readings to indicate satisfactory operation of the pressure sensor, the spring ring engaging a circumferential groove formed in the wall of the valve body bore and cooperating therewith to retain the sensor within the valve body bore.

23. A method according to claim 22 further including the steps of:

(g) removing the monitoring equipment; and

(h) attaching a housing to the valve body, said housing enclosing the pressure sensor and forming a hermetic seal with the valve body.