Electric motor-driven impeller-type air pump

• US 5,049,770 A
• Filed: 03/26/1990
• Issued: 09/17/1991
• Est. Priority Date: 03/26/1990
• Status: Expired due to Term

• Current Assignee: Borg-Warner Automotive Incorporated (BorgWarner Incorporated)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Brigham, Joseph P., Sherrill, Steven W., Herlache, Russell L., Gaeth, Gerald A.
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): HASZKO, DENNIS
• Application Number:
  US07/503,596
• Time in Patent Office: 540 Days
• Field of Search: 310/43, 310/89, 310/51, 310/62, 310/63, 417/423.1, 417/423.7, 417/423.9, 417/279, 417/423.14, 98/116, 55/417
• US Class Current: 310/89
• CPC Class Codes: F02B 63/06 for pumps
• CPC Class Codes: F04D 23/008 Regenerative pumps for liquids or for liquids and elastic fluids F04D5/002
• CPC Class Codes: F04D 29/624 especially adapted for elastic fluid pumps
• CPC Class Codes: F04D 29/664 by means of sound absorbing material
• CPC Class Codes: H02K 5/08 Insulating casings
• CPC Class Codes: H02K 5/24 specially adapted for suppression or reduction of noise or vibrations

Abstract

An electrically operated air pump for supplying air to the exhaust system of an internal combustion engine having a central mounting plate which is integral with the electric motor assembly. The armature shaft of the electric motor drives an impeller within a working chamber defined by an impeller housing and one side of the mounting plate. A silencer housing encloses the motor assembly and contains an air circuit for channeling air to and from the working chamber of the pump. The air circuit contains a solenoid operated air valve for restriction of outlet air, and sound insulation means for external sound reduction. The central mounting plate, impeller, impeller housing, and silencer housing are constructed of a polymeric material which allows complex features to be molded into the part thereby minimizing machining and assembly complexity.

Claims

1. An electric air pump, having a central mounting plate, an electric motor assembly integral with a first side of said plate, and an impeller housing secured to a second side of said plate, said motor assembly having an armature shaft that extends, through a central aperture in said mounting plate, into the working chamber defined between said mounting plate and said impeller housing, to support and drive an impeller within said chamber to induce air flow through said chamber, from an inlet to an outlet, said air pump further comprising:

bearing mounting means integral with said first side of said mounting plate and coaxial with said central aperture having an armature shaft bearing positioned therein, and brush mounting means positioned relative to said central aperture having a brush assembly attached thereto, said motor armature shaft centrally supported by said armature shaft bearing in an operational relationship with said brush assembly;

a motor upper housing extending over said motor armature shaft and said brush assembly, and cooperating with said first side of said motor plate to enclose said motor;

a silencer housing enclosing said electric motor assembly having a first closed end, and a second open end which cooperates with said first side of said mounting plate to enclose said motor assembly, a central motor chamber axially extending from said first end to said second end to isolate said motor assembly within said silencer housing, an air circuit disposed radially outwardly and coaxially of said central motor chamber having an air inlet chamber and an air outlet chamber, said outlet chamber isolated from said inlet chamber, a silencer housing inlet port, interconnected to said inlet chamber for introduction of air into said silencer housing, and a silencer housing outlet port, interconnected to said outlet chamber for passage of air out of said silencer housing;

an impeller chamber inlet, extending through said mounting plate, for introducing air from said inlet chamber to the inlet side of said impeller chamber;

an impeller chamber outlet, extending through said mounting plate, for exhausting air from the outlet side of said impeller chamber to said outlet chamber; and

sound insulating means, disposed in said inlet and said outlet chambers.

2. An electric air pump, as defined in claim 1, further comprising:

a valve disposed within said air circuit for restricting air flow from said air pump.

3. An electric air pump, as defined in claim 2, further comprising:

a valve seat integral with the interior of said silencer housing and extending about the perimeter of said silencer housing outlet port;

said air valve comprising a solenoid, disposed within said air outlet chamber, which operates a valve member to engage said valve seat.

4. An electric air pump, as defined in claim 3, further comprising:

an electric circuit for controlling said motor assembly and said solenoid, in which said motor and said solenoid may be simultaneously grounded to prevent current, generated during motor coastdown, from delaying valve closure.

8. An electric air pump, as defined in claim 1, wherein said silencer housing air inlet chamber comprises a first inlet port chamber, integral with said silencer housing inlet port and having sound insulating means disposed therein, a filter chamber, interconnected with said first inlet chamber and having a filter element disposed therein and oriented, with respect to the air flow, so as to induce radial flow through said element, and an induction port chamber, interconnected with said filter chamber and said impeller chamber inlet and having sound insulating means disposed therein.

9. An electric air pump, as defined in claim 1, wherein said silencer housing inlet and outlet ports are located on said first closed end of said housing.

5. An electric air pump, having a central mounting plate, an electric motor assembly integral with a first side of said plate, and an impeller housing secured to a second side of said plate, said motor assembly having an armature shaft that extends, through a central aperture in said mounting plate, into the working chamber defined between said mounting plate and said impeller housing, to support and drive an impeller within said chamber to induce air flow through said chamber, from an inlet to an outlet, said air pump further comprising:

bearing mounting means integral with said first side of said mounting plate and coaxial with said central aperture having an armature shaft bearing positioned therein, and brush mounting means positioned relative to said central aperture having a brush assembly attached thereto, said motor armature shaft centrally supported by said armature shaft bearing in an operational relationship with said brush assembly;

a motor upper housing extending over said motor armature shaft and said brush assembly, and cooperating with said first side of said motor plate to enclose said motor;

wherein said impeller housing is constructed of a polymeric material having a portion of said impeller chamber formed integrally therein and having a pilot aperture molded therein for supporting the impeller end of said motor armature shaft to thereby position said shaft and said impeller relative to said impeller chamber.

6. An electric air pump, as defined in claim 5, wherein said pilot aperture comprises radially inwardly extending webs whose end portions cooperate to form a supporting bearing surface for said armature shaft, said surface subject to wear in cases of misalignment between said armature shaft and said impeller housing thereby providing for a self-seating bearing surface.

7. An electric air pump, having a central mounting plate, an electric motor assembly integral with a first side of said plate, and an impeller housing secured to a second side of said plate, said motor assembly having an armature shaft that extends, through a central aperture in said mounting plate, into the working chamber defined between said mounting plate and said impeller housing, to support and drive an impeller within said chamber to induce air flow through said chamber, from an inlet to an outlet, said air pump further comprising:

bearing mounting means integral with said first side of said mounting plate and coaxial with said central aperture having an armature shaft bearing positioned therein, and brush mounting means positioned relative to said central aperture having a brush assembly attached thereto, said motor armature shaft centrally supported by said armature shaft bearing in an operational relationship with said brush assembly;

a motor upper housing extending over said motor armature shaft and said brush assembly, and cooperating with said first side of said motor plate to enclose said motor;

said central mounting plate constructed of a polymeric material having a portion of said impeller chamber formed integrally within said second side of said plate.

10. An electric air pump, having a central mounting plate, an electric motor assembly integral with a first side of said plate, and an impeller housing secured to a second side of said plate, said motor assembly having an armature shaft that extends, through a central aperture in said mounting plate, into the working chamber defined between said mounting plate and said impeller housing, to support and drive an impeller within said chamber to induce air flow through said chamber, from an inlet to an outlet, said air pump further comprising:

bearing mounting means integral with said first side of said mounting plate and coaxial with said central aperture having an armature shaft bearing positioned therein, and brush mounting means positioned relative to said central aperture having a brush assembly attached thereto, said motor armature shaft centrally supported by said armature shaft bearing in an operational relationship with said brush assembly;

a motor upper housing extending over said motor armature shaft and said brush assembly, and cooperating with said first side of said motor plate to enclose said motor;

said impeller comprising a central hub portion and an outer blade portion, said central hub portion having a series of elongated arcuate recesses formed therein;

wherein the air trapped within said recesses forms a dynamic air seal between said central hub portion and the opposing wall of said working chamber as said impeller hub rotates relative to said chamber, thereby reducing air leakage between the inlet and the outlet side of said working chamber.

11. An electric air pump, as defined in claim 10, wherein said opposing wall of said working chamber has similarly shaped opposing recesses which act in concert with said recesses in said impeller hub to form a dynamic air seal between said surfaces.

12. An electric air pump, having a central mounting plate, an electric motor assembly integral with a first side of said plate, and an impeller housing secured to a second side of said plate, said motor assembly having an armature shaft that extends, through a central aperture in said mounting plate, into the working chamber defined between said mounting plate and said impeller housing, to support and drive an impeller within said chamber to induce air flow through said chamber, a silencer housing enclosing said electric motor assembly having a first closed end, and a second open end which cooperates with said first side of said mounting plate to enclose said motor assembly, a central motor chamber axially extending from said first end to said second end to isolate said motor assembly within said silencer housing, an air circuit disposed radially outwardly and coaxially of said central motor chamber having an air inlet chamber and an air outlet chamber, said outlet chamber isolated from said inlet chamber, a silencer housing inlet port, interconnected to said inlet chamber for introduction of air into said silencer housing, and a silencer housing outlet port, interconnected to said outlet chamber for passage of air out of said silencer housing;

an impeller chamber inlet, extending through said mounting plate, for introducing air from said inlet chamber to the inlet side of said impeller chamber;

an impeller chamber outlet, extending through said mounting plate, for exhausting air from the outlet side of said impeller chamber to said outlet chamber; and

sound insulating means, disposed in said inlet and said outlet chambers.

13. An electric air pump, as defined in claim 12, further comprising:

a valve disposed within said air circuit to restrict air flow from said air pump.

14. An electric air pump, as defined in claim 13, further comprising:

a valve seat integral with the interior of said silencer housing and extending about the perimeter of said silencer housing port;

said air valve comprising a solenoid, disposed within said air outlet chamber, having a valve member operable to engage said valve seat.

15. An electric air pump, as defined in claim 14, further comprising:

an electric circuit for controlling said motor assembly and said solenoid, in which said motor and said solenoid may be simultaneously grounded to prevent current, generated during motor coastdown, from delaying valve closure.

16. An electric air pump, as defined in claim 12, wherein said silencer housing air inlet chamber comprises an inlet port chamber, integral with said silencer housing inlet port and having sound insulating means disposed therein, a filter chamber, interconnected with said inlet chamber and having a filter element disposed therein and oriented, with respect to the air flow, so as to induce radial flow through said element, and an induction port chamber, interconnected with said filter chamber and said impeller chamber inlet and having sound insulating means disposed therein.

17. An electric air pump, as defined in claim 12, wherein said silencer housing inlet and outlet ports are located on said first closed end of said housing.

18. An electric air pump, having a central mounting plate, an electric motor assembly integral with a first side of said plate, a silencer housing which cooperates with said first side of said mounting plate to enclose said motor assembly, an impeller housing secured to a second side of said plate, said motor assembly having an armature shaft that extends, through a central aperture in said mounting plate, into the working chamber defined between said mounting plate and said impeller housing to support and drive an impeller within said chamber to induce air flow through said chamber, said air pump further comprising:

lock recesses formed about the circumference of said mounting plate, said recesses having lock ramps formed integrally therein;

lock arms, corresponding in number and location to said lock recesses, extending outwardly from one of said impeller housing and said silencer housing configured to matingly engage said corresponding mounting plate lock ramps in a bayonet fashion to hold said mounting plate and said one of said impeller housing and said silencer housing in engagement therewith;

lock nibs, extending outwardly from the side of said one of said impeller housing and said silencer housing, and positioned axially from said lock recesses; and

lock tabs, extending axially outwardly from the other of said impeller housing and said silencer housing, said tabs having recesses formed on the inner sides thereof for engagement with said lock nibs, said tabs extendible through said locking recesses, adjacent said lock arms engaged in said lock recesses, to thereby hold said lock arms in engagement therewith and to retain said housing, said mounting plate, and said silencer housing in an axially fixed relationship.

19. An electric air pump, having an impeller housing, drive means having an armature shaft that extends into the working chamber of said impeller housing, to support and drive an impeller within said chamber to induce air flow through said chamber, from an inlet to an outlet, said impeller comprising a central hub portion and an outer blade portion, said central hub portion having a series of elongated arcuate recesses formed therein;

wherein air trapped within said recesses forms a dynamic air seal between said central hub portion and the opposing wall of said working chamber as said impeller hub rotates relative to said chamber, thereby reducing air leakage between the inlet and the outlet side of said working chamber.

20. An air pump, as defined in claim 19, further comprising arcuate recesses formed in the wall of said working chamber opposing said recesses formed in said central hub portion, which act in concert with said recesses in said impeller hub to form a dynamic air seal between said surfaces.

21. An air pump, as defined in claim 19, wherein said impeller housing is constructed of a polymeric material having a portion of said impeller chamber formed integrally therein and having a pilot aperture molded therein for supporting the impeller end of said motor armature shaft to thereby position said shaft and said impeller relative to said impeller chamber.

22. An air pump, as defined in claim 21, wherein said pilot aperture comprises radially inwardly extending webs whose end portions cooperate to form a supporting bearing surface for said armature shaft, said surface subject to wear in cases of misalignment between said armature shaft and said impeller housing thereby providing for a self-seating bearing surface.