Hall-effect ferrous-article-proximity sensor assembly

• US 5,581,179 A
• Filed: 05/31/1995
• Issued: 12/03/1996
• Est. Priority Date: 05/31/1995
• Status: Expired due to Term

• Current Assignee: Allegro Microsystems Incorporated (Sanken Electric Company Limited)
• Original Assignee: Allegro Microsystems Incorporated (Sanken Electric Company Limited)
• Inventors: Gilbert, Peter J., Clapp, Terry, Engel, Raymond W., Vig, Ravi, Tu, Teri
• Primary Examiner(s): Strecker, Gerard R.
• Application Number:
  US08/454,916
• Time in Patent Office: 552 Days
• Field of Search: 324/173, 324/174, 324/207.15, 324/207.2, 324/207.21, 324/207.25, 324/207.26, 324/235, 324/251, 324/252, 384/448, 174/52.1, 174/52.2, 174/52.3, 307/116, 307/117, 123/617, 73/517 R, 73/518-520, 73/DIG. 3
• US Class Current: 324/207.2
• CPC Class Codes: G01D 11/245 Housings for sensors
• CPC Class Codes: G01D 5/147 influenced by the movement of a third element, the position of Hall device and the source of magnetic field being fixed in respect to each other
• CPC Class Codes: G01P 3/487 delivered by rotating magnets

Abstract

This invention is a magnetic-field sensor assembly comprising a preformed housing shell having a first end which includes an opening, and a second end which includes a window and having a cylindrical shape with a flattened portion to produce a truncated circular cross-section, a sensor package including an integrated-circuit magnetic-field-sensor chip encapsulated in a protective body with first and second opposite and mutually parallel faces and a plurality of integral conductive leads, each lead having a proximal portion, a distal portion, and a central portion, the proximal portion of each of said plurality of leads extending from said body, the central portion of said plurality of leads extending away from the body and positioned substantially normal the faces of the body, said sensor-package body being positioned in said housing shell part way through said window with said one body face extending outwardly from said housing shell and with said lead distal portions extending from said housing shell through said opening, a magnet having a first end and a second end and positioned in said housing shell with said first end adjacent to said second sensor-package body face, and an endcap adapted to close said opening in said housing shell.

Claims

1. A magnetic-field sensor assembly comprising:

(a) a preformed housing shell having a first end which includes an opening with a periphery, and a second end which includes a window, and having an external cylindrical shape with a flattened portion to produce a truncated circular cross-section;

(b) a sensor package including an integrated-circuit magnetic-field-sensor chip encapsulated in a protective body with a second opposite and mutually parallel faces and a plurality of integral conductive leads, each lead forming an uninterrupted conductive path from said chip within said protective body through said first end opening, each lead having a proximal portion, a distal portion, and a central portion, the proximal portion of each of said plurality of leads extending from said body, the central portion of said plurality of leads extending away from the body and positioned substantially normal the faces of the body, said sensor-package body being positioned in said housing shell part way through said window with said first body face extending outwardly from said housing shell and with said lead distal portions extending from said housing shell through said opening at the periphery;

(c) a magnet having a first end and a second end and positioned in said housing shell with said first end adjacent to said second sensor-package body face; and

(d) closing means adapted to close said opening in said housing shell.

2. A sensor assembly as recited in claim 1, especially adapted for detecting the passage of adjacent ferromagnetic objects.

3. A sensor assembly as recited in claim 1, especially adapted for detecting the presence of adjacent ferromagnetic objects.

4. A sensor assembly as recited in claim 1, especially adapted for detecting the passage of adjacent ferromagnetic gear teeth.

5. A sensor assembly as recited in claim 1, especially adapted for detecting the presence of adjacent ferromagnetic gear teeth.

6. A sensor assembly as recited in claim 1, wherein the housing shell is preformed and of such dimensions with respect to the other components that, when the assembly is formed, the sensor package and magnet are biased toward one another.

7. A sensor assembly as recited in claim 1, wherein adjacent leads are spaced apart a constant distance along entire lead length.

8. A sensor assembly as recited in claim 1, wherein the leads extend from the chip body in a proximal lead plane that is parallel with the planes of said faces and spaced from the plane of the said first face so that the portion of the leads in the proximal lead plane do not extent into the plane of the said first face.

9. A sensor assembly as recited in claim 1, wherein said housing shell is provided with an inner surface with a side wall between the ends of the housing shell, which side wall has a curved portion and a second portion which forms a flat structure.

10. A magnetic-field sensor assembly comprising:

(a) a preformed housing shell having a first end which includes an opening, and a second end which includes a window;

(b) a sensor package including an integrated-circuit magnetic-field-sensor chip encapsulated in a protective body with first and second opposite and mutually parallel faces and a plurality of conductive leads, each lead having a proximal portion, a distal portion, and a central portion, the proximal portion of each of said plurality of leads extending from said body, the central portion of said plurality of leads extending away from the body and positioned substantially normal to the faces of the body, said sensor-package body being positioned in said housing shell part way through said window with said first body face extending outwardly from said housing shell and with said lead distal portions extending from said housing shell through said opening;

(c) a magnet having a first end and a second end and positioned in said housing shell with said first end adjacent to said second sensor-package body face; and

(d) an endcap adapted to close said opening in said housing shell, wherein said housing shell is provided with an outer surface between the ends of the housing shell, which outer surface has a cross-section in the form of a first truncated circle, and wherein said housing shell is provided with an inner surface with a side wall between the ends of the housing shell, which side wall has a first curved portion and a second portion which forms a flat structure, so that the inner surface, as defined by the curved portion and the flat structure, has a cross-section in the form of a second truncated circle, and grooves formed in said second portion which allow the leads to pass along the shell within the cross-sectional segment which complements said second truncated circle, so as to allow minimization of the diameter of the said first truncated circle.

11. A magnetic-field sensor assembly comprising:

(a) a preformed housing shell having a first end which includes an opening, and a second end which includes a window;

(b) a sensor package including an integrated-circuit magnetic-field-sensor chip encapsulated in a protective body with first and second opposite and mutually parallel faces and a plurality of conductive leads, each lead having a proximal portion, a distal portion, and a central portion, the proximal portion of each of said plurality of leads extending from said body, the central portion of said plurality of leads extending away from the body and positioned substantially normal to the faces of the body, said sensor-package body being positioned in said housing shell part way through said window with said first body face extending outwardly from said housing shell and with said lead distal portions extending from said housing shell through said opening;

(c) a magnet having a first end and a second end and positioned in said housing shell with said first end adjacent to said second sensor-package body face; and

(d) an endcap adapted to close said opening in said housing shell, wherein said housing shell is provided with an inner surface with a side wall between the ends of the housing shell, which side wall has a first curved portion and a second portion which forms a flat structure, said second portion being formed of parallel lands and grooves, said grooves being adapted to receive and maintain a fixed parallel spacing of the leads as they pass through the inside of the housing shell.

12. A magnetic-field sensor assembly comprising:

(a) a preformed housing shell having a first end which includes an opening, and a second end which includes a window;

(b) a sensor package including an integrated-circuit magnetic-field-sensor chip encapsulated in a protective body with first and second opposite and mutually parallel faces and a plurality of conductive leads, each lead having a proximal portion, a distal portion, and a central portion, the proximal portion of each of said plurality of leads extending from said body, the central portion of said plurality of leads extending away from the body and positioned substantially normal to the faces of the body, said sensor-package body being positioned in said housing shell part way through said window with said first body face extending outwardly from said housing shell and with said lead distal portions extending from said housing shell through said opening;

(c) a magnet having a first end and a second end and positioned in said housing shell with said first end adjacent to said second sensor-package body face; and

(d) an endcap adapted to close said opening in said housing shell, wherein said housing shell is provided with an inner surface which includes grooves which have a bottom and two upper edges, and which grooves are deep enough that when a lead is placed in the bottom of a groove, the uppermost part of the lead is substantially below the upper edges of the groove, so that a flat object resting on the upper edges of the groove will not be in contact with the lead.

13. A magnetic-field sensor assembly comprising:

(a) a preformed housing shell having a first end which includes an opening, and a second end which includes a window;

(b) a sensor package including an integrated-circuit magnetic-field-sensor chip encapsulated in a protective body with first and second opposite and mutually parallel faces and a plurality of conductive leads, each lead having a proximal portion, a distal portion, and a central portion, the proximal portion of each of said plurality of leads extending from said body, the central portion of said plurality of leads extending away from the body and positioned substantially normal to the faces of the body, said sensor-package body being positioned in said housing shell part way through said window with said first body face extending outwardly from said housing shell and with said lead distal portions extending from said housing shell through said opening;

(c) a magnet having a first end and a second end and positioned in said housing shell with said first end adjacent to said second sensor-package body face; and

(d) an endcap adapted to close said opening in said housing shell, wherein said housing shell is provided with an inner surface which includes grooves which have a bottom and two upper edges, and which grooves are deep enough that when a lead is placed in the bottom of a groove, the uppermost part of the lead is substantially below the upper edges of the groove, so that a flat object resting on the upper edges of the groove will not be in contact with the lead, and wherein the chip body is held immovable and as a result the proximal ends of the leads are held at the bottom of the grooves, and wherein the endcap is provided with endcap grooves which engage the distal portion of the leads and as a result the distal portion of the leads are held at the bottom of the grooves, so that the leads are held at the bottom of the grooves and separate from one another.

14. A magnetic-field sensor assembly comprising:

(a) a preformed housing shell having a first end which includes an opening, and a second end which includes a window;

(b) a sensor package including an integrated-circuit magnetic-field-sensor chip encapsulated in a protective body with first and second opposite and mutually parallel faces and a plurality of conductive leads, each lead having a proximal portion, a distal portion, and a central portion, the proximal portion of each of said plurality of leads extending from said body, the central portion of said plurality of leads extending away from the body and positioned substantially normal to the faces of the body, said sensor-package body being positioned in said housing shell part way through said window with said first body face extending outwardly from said housing shell and with said lead distal portions extending from said housing shell through said opening;

(c) a magnet having a first end and a second end and positioned in said housing shell with said first end adjacent to said second sensor-package body face; and

(d) an endcap adapted to close said opening in said housing shell, wherein said housing shell is provided with an inner surface which includes grooves which have a bottom and two upper edges, and which grooves are deep enough that when a lead is placed in the bottom of a groove, the uppermost part of the lead is substantially below the upper edges of the groove, so that an object resting on the upper edges of the groove will not be in contact with the lead, and wherein the chip body is held immovable and as a result the proximal ends of the leads are held at the bottom of the grooves, and wherein the endcap is provided with endcap grooves which engage the distal portion of the leads and as a result the distal portion of the leads are held at the bottom of the grooves, so that the leads are held at the bottom of the grooves and separate from one another.

15. A magnetic-field sensor assembly comprising:

(a) a preformed housing shell having a first end which includes an opening, and a second end which includes a window;

(b) a sensor package including an integrated-circuit magnetic-field-sensor chip encapsulated in a protective body with first and second opposite and mutually parallel faces and a plurality of conductive leads, each lead having a proximal portion, a distal portion, and a central portion, the proximal portion of each of said plurality of leads extending from said body in a common plane, the central portion of said plurality of leads extending away from the body and positioned substantially normal the faces of the body, said sensor-package body being positioned in said housing shell part way through said window with said first body face extending outwardly from said housing shell and with said lead distal portions extending from said housing shell through said opening;

(c) a magnet having a first end and a second end and positioned in said housing shell with said first end adjacent to said second sensor-package body face; and

(d) a closing means adapted to obstruct said opening in said housing shell so that items in the shell cannot exit the shell, wherein said leads are integral, each forming an uninterrupted conductive path from said chip within said protective body through said closing means at said first end opening.

16. A sensor assembly as recited in claim 15, wherein the housing shell is preformed and of such dimensions with respect to the other components that, when the assembly is formed, the sensor package and magnet are biased toward one another.

17. A sensor assembly as recited in claim 15, wherein adjacent leads are spaced apart a constant distance along the entire lead length.

18. A sensor assembly as recited in claim 15, wherein the leads extend from the chip body in a proximal lead plane that is parallel with the planes of said faces and spaced from the plane of the said first face so that the portion of the leads in the proximal lead plane do not extend into the plane of said first face.

19. A sensor assembly as recited in claim 15, wherein said first face of said body has at least two opposite edges that are beveled, and said window of said shell has at least two opposite edges that have inwardly-facing bevels, the beveled edges of said face conforming to the bevels of said window so that the body is stopped from exiting through said window, and the body is restricted from lateral movement with respect to the shell.

20. A sensor assembly as recited in claim 15, wherein said first end of said shell includes a plurality of notches into which the leads can be bent so that the leads do not extend rearward of the opening of said first end of the shell.

21. A sensor assembly as recited in claim 15, wherein the closing means is provided with grooves each of which engages the distal portion of a separate lead as it exits the shell and as a result the distal portion of the leads are held separate as they exit the shell.

22. A sensor assembly as recited in claim 15, wherein said sensor assembly is designed to be modular so that it can be associated with a range of signal processing equipment.

23. A sensor assembly as recited in claim 15, wherein additional electronic circuitry is physically associated with the closing means and adapted to be electrically connected to at least one of the leads.