Method and apparatus for attaching a sensor assembly in a control unit

• US 20040000204A1
• Filed: 05/27/2003
• Published: 01/01/2004
• Est. Priority Date: 06/28/2002
• Status: Active Grant

• Current Assignee: Siemens VDO Automotive Corporation (Siemens AG)
• Original Assignee: Siemens VDO Automotive Corporation (Siemens AG)
• Inventors: Clark, Jeffrey A.
• Granted Patent: US 6,913,472 B2
• Time in Patent Office: Days
• US Class Current: 73/866.5
• CPC Class Codes: G01D 11/245 Housings for sensors
• CPC Class Codes: G01P 1/023 for acceleration measuring devices
• CPC Class Codes: H05K 1/141 One or more single auxiliary printed circuits mounted on a main printed circuit, e.g. modules, adapters H05K1/142 and H05K1/147 take precedence
• CPC Class Codes: H05K 2201/0999 Circuit printed on or in housing, e.g. housing as PCB; Circuit printed on the case of a component; PCB affixed to housing
• CPC Class Codes: H05K 2201/10151 Sensor
• CPC Class Codes: H05K 2201/10598 Means for fastening a component, a casing or a heat sink whereby a pressure is exerted on the component towards the PCB
• CPC Class Codes: H05K 2201/2036 Permanent spacer or stand-off in a printed circuit or printed circuit assembly

Abstract

A control unit for a safety restraint device includes a main printed circuit board that supports lateral and vertical acceleration sensors and an auxiliary printed circuit board that supports rollover sensors. The main and auxiliary printed circuit boards are spaced apart from and are positioned in an overlapping relationship to each other within a housing. A pin connection provides electrical connection between the main and auxiliary printed circuit boards to permit signal transfers between the main and auxiliary printed circuit boards. A common fastener is used to connect both the main and auxiliary printed circuit boards to the housing. A cover is used to enclose the main and auxiliary printed circuit boards within the housing. The fastener extends through the cover, through both the main and auxiliary printed circuit boards, and finally into the housing.

Claims

1. A sensor assembly for a safety restraint control unit comprising:

a main printed circuit board;

a first sensor supported on said main printed circuit board;

an auxiliary printed circuit board electrically connected to said main printed circuit board wherein said auxiliary printed circuit board is non-coplanar with said main printed circuit board;

a second sensor supported on said auxiliary printed circuit board; and

at least one attachment member that attaches both said main and auxiliary printed circuit boards to a housing.

2. The sensor assembly set forth in claim 1 wherein said auxiliary printed circuit board is spaced apart from and positioned in an overlapping relationship to said main printed circuit board.

3. The sensor assembly set forth in claim 1 wherein said attachment member comprises at least one fastener having a body portion that concurrently secures said main and auxiliary printed circuit boards to said housing.

4. The sensor assembly set forth in claim 1 including a rigid spacer having a first end in direct abutment with said main printed circuit board and a second end in direct abutment with said auxiliary printed circuit board wherein said rigid spacer includes a central bore that surrounds said attachment member.

5. The sensor assembly set forth in claim 4 including a cover for enclosing said main and auxiliary printed circuit boards within said housing.

6. The sensor assembly set forth in claim 5 wherein said attachment member comprises at least one fastener having a body member that extends through said cover, said main printed circuit board, said rigid spacer, and said auxiliary printed circuit board and wherein said body member terminates at a distal end that is embedded within a wall of said housing.

7. The sensor assembly set forth in claim 1 wherein said first sensor comprises at least one acceleration sensor for measuring a vehicle acceleration and wherein said second sensor comprises at least one rollover sensor for measuring a vehicle angular roll rate.

8. A control unit and sensor assembly for a safety restraint device comprising:

a housing;

a first printed circuit board supported by said housing;

a second printed circuit board supported by said housing, said second printed circuit board being spaced apart from and positioned in an overlapping relationship to said first circuit board;

at least one sensor mounted on said second printed circuit board and electrically connected to said first-printed circuit board; and

at least one attachment member that simultaneously secures said first and second printed circuit boards directly to said housing.

9. The assembly set forth in claim 8 wherein said at least one sensor comprises a rollover sensor that measures a vehicle angular rate.

10. The assembly set forth in claim 9 including at least one acceleration sensor mounted on said first circuit board.

11. The assembly set forth in claim 8 wherein said first circuit board includes a first opening, said second circuit board includes a second opening, and said housing includes a third opening, said first, second, and third openings being positioned in alignment with each other to receive said attachment member.

12. The assembly set forth in claim 11 including a rigid tubular support positioned between said first and second printed circuit boards and in alignment with said first, second, and third openings.

13. The assembly set forth in claim 12 including a cover attached to said housing to enclose said first and second printed circuit boards within said housing.

14. The assembly set forth in claim 13 wherein said attachment member comprises at least one fastener having a body portion inserted through said cover, said first printed circuit board, said rigid tubular support, and said second printed circuit board and wherein said body portion terminates at a distal end that is embedded within a wall of said housing.

15. The assembly set forth in claim 11 wherein said first printed circuit board comprises a primary printed circuit board and said second printed circuit board comprises an auxiliary printed circuit board electrically connected to said primary printed circuit board with a plurality of pins.

16. A method for assembling a safety restraint device control unit and sensor assembly comprising the steps of:

(a) positioning main and auxiliary printed circuit boards in an overlapping relationship to each other; and

(b) simultaneously fastening the main and auxiliary printed circuit boards to a sensor housing with a common fastener.

17. The method set forth in claim 16 including the steps of mounting at least one rollover sensor to the auxiliary printed circuit board for generating a vehicle angular rate signal, mounting at least one acceleration sensor to the main printed circuit board for generating a vehicle acceleration signal, and electrically connecting the auxiliary printed circuit board to the main printed circuit board.

18. The method set forth in claim 17 including the steps of abutting a first end of a rigid tubular member against the main printed circuit board, abutting a second end of the rigid tubular member against the auxiliary printed circuit board, and inserting the fastener through main printed circuit board, then through the rigid tubular member, then through the auxiliary printed circuit board, and finally into the sensor housing.

19. The method set forth in claim 18 including the step of abutting a portion of the auxiliary printed circuit board against a ledge formed within the sensor housing.