Electromagentic compressor clutch with combined torque cushion and armature cooling

• US 5,642,798 A
• Filed: 03/22/1996
• Issued: 07/01/1997
• Est. Priority Date: 03/22/1996
• Status: Expired due to Term

• Current Assignee: Mahle International GmbH (MAHLE-STIFTUNG GmbH)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Marker, Richard Lee, Muirhead, Hugh James
• Primary Examiner(s): Pitts, Andrea L.
• Application Number:
  US08/620,187
• Time in Patent Office: 466 Days
• Field of Search: 192/84.961, 192/209, 192/113.23
• US Class Current: 192/84.961
• CPC Class Codes: F16D 13/72 Features relating to cooling
• CPC Class Codes: F16D 2027/007 Bias of an armature of an electromagnetic clutch by flexing of substantially flat springs, e.g. leaf springs
• CPC Class Codes: F16D 27/112 with flat friction surfaces, e.g. discs

Abstract

An electromagnetic clutch for an automotive air conditioning compressor supports the armature co axial to, and facing, a pulley friction disk with a novel support structure that self cools the armature, as well as providing a torque cushion. A multi lobed drive plate is welded to a compressor shaft mounted hub, while a similarly shaped armature support disk turns freely on the outer surface of the hub, supporting armature rings on spring fingers co axial and parallel to a belt driven pulley friction disk. The lobes of the drive plate and support disk are aligned in three pairs, with a significant axial gap between, and extend radially over the entire outer face of the armature rings, while leaving most of the outer face exposed to the ambient air. A layer of resilient elastomer is bonded between the aligned lobes of the drive plate and support disk, holding them together, limiting the degree to which the support disk can twist on the hub, and cushioning the shock of initial engagement. The elastomer layer is thick enough that the leading edges thereof disturb ambient air as the rotate, drawing air in and over the armature rings in fan like fashion to cool them.

Claims

1. An electromagnetic clutch assembly in combination with an automotive air conditioning compressor having a central drive shaft and a powered rotor supported for free rotation about said drive shaft, said powered rotor having a generally annular friction disk coaxial to said drive shaft and facing in one axial direction ralative a generative to said compressor, said clutch assembly comprising,

a generally cylindrical, central hub fixed to said drive shaft,

a generally annular armature of magnetic material having an outer edge with a diameter comparable to said friction disk so as to be capable of being supported in an operative position generally coaxial thereto with an outer face exposed to ambient air and an inner face axially spaced from said friction disk with a predetermined gap sufficiently small to allow said armature inner face to be electromagnetically pulled into engagement with said friction disk so as to rotate therewith when said clutch is actuated,

a multi lobed, substantially rigid armature support having an inner edge fixed to said hub and a plurality of rigid, generally radially directed lobes extending continuously from said inner edge, radially outwardly and along said armature outer face to outer ends located substantially at the outer edge of said armature, each of said lobes further being sufficiently axially thick to disturb a substantial volume of ambient air as they rotate but being sufficiently narrow to leave most of said armature outer face exposed to ambient air, and,

axially flexible and circumferentially and radially stiff spring means fixing said armature non turnably to said armature support lobes in said operative position such that said armature may be pulled electromagnetically against said friction disk and released to return to said operative position,

whereby, when said clutch is actuated and said armature engages and rotates with said friction disk, said armature support lobes co rotate to translate power to said shaft and concurrently disturb and pull ambient air toward and into said armature outer face in fan like fashion, thereby cooling said armature.

2. An electromagnetic clutch assembly in combination with an automotive air conditioning compressor having a central drive shaft and a powered rotor supported for free rotation about said drive shaft, said powered rotor having a generally annular friction disk coaxial to said drive shaft and facing in one axial direction relative to said compressor, said clutch assembly comprising,

a generally cylindrical, central hub fixed to said drive shaft,

a generally annular armature of magnetic material having an outer edge with a diameter comparable to said friction disk so as to be capable of being supported in an operative position generally coaxial thereto with an outer face exposed to ambient air and an inner face axially spaced from said friction disk with a predetermined gap sufficiently small to allow said armature inner face to be electromagnetically pulled into engagement with said friction disk so as to rotate therewith when said clutch is actuated,

a multi-lobed, rigid drive plate having an inner edge fixed to said hub and a plurality of rigid, generally radially directed lobes axially spaced from said armature outer face and extending continuously from said inner edge, radially outwardly to outer ends located substantially at the outer edge of said armature, said drive plate lobes being sufficiently narrow to leave most of said armature outer face exposed to ambient air,

a multi lobed, rigid armature support disk located axially between said armature and drive plate, said armature support having a plurality of lobes generally congruent to said drive plate lobes,

a layer of resilient elastomer integrally molded between and joining said drive plate and armature support disk lobes together, said elastomer layer being sufficiently flexible to absorb the shock of engagement between said armature and friction disk but sufficiently axially thick both to translate torque between said congruent lobes and also to disturb a substantial volume of ambient air as they rotate, and,

axially flexible and circumferentially and radially stiff spring means fixing said armature non turnably to said armature support disk lobes in said operative position such that said armature may be pulled electromagnetically against said friction disk and released to return to said operative position,

whereby, when said clutch is actuated and said armature engages and rotates with said friction disk, said elastomer layer cushions the shock of engagement armature as said armature support disk inner edge turns on said hub bearing surface, said drive plate and armature support disk lobes co rotate to translate power to said shaft, while, concurrently, said elastomer layer disturbs and pulls ambient air toward and into said armature outer face in fan like fashion, thereby cooling said armature.

3. An electromagnetic clutch assembly in combination with an automotive air conditioning compressor having a central drive shaft and a powered rotor supported for free rotation about said drive shaft, said powered rotor having a generally annular friction disk coaxial to said drive shaft and facing in one axial direction relative to said compressor, said clutch assembly comprising,

a generally cylindrical, central hub fixed to said drive shaft, said hub having a cylindrical outer bearing surface and a radially extending shoulder,

a generally annular armature of magnetic material having an outer edge with a diameter comparable to said friction disk so as to be capable of being supported in an operative position generally coaxial thereto with an outer face exposed to ambient air and an inner face axially spaced from said friction disk with a predetermined gap sufficiently small to allow said armature inner face to be electromagnetically pulled into engagement with said friction disk so as to rotate therewith when said clutch is actuated,

a multi lobed, rigid drive plate having an inner edge fixed to said hub on the outside of said shoulder and a plurality of rigid, generally radially directed lobes axially spaced from said armature outer face and extending continuously from said inner edge, radially outwardly to outer ends located substantially at the outer edge of said armature, said drive plate lobes being sufficiently narrow to leave most of said armature outer face exposed to ambient air,

a multi lobed, rigid armature support disk located axially between said armature and drive plate, said armature support disk having a circular inner edge piloted on said hub bearing surface in abutment with the inner side of said shoulder and also having a plurality of lobes generally congruent to said drive plate lobes,

a layer of resilient elastomer integrally molded between and joining said drive plate and armature support disk lobes together, said elastomer layer being sufficiently flexible to absorb the shock of engagement between said armature and friction disk but sufficiently axially thick both to translate torque between said congruent lobes and also to disturb a substantial volume of ambient air as they rotate, and,

axially flexible and circumferentially and radially stiff spring means fixing said armature non turnably to said armature support disk lobes in said operative position such that said armature may be pulled electromagnetically against said friction disk and released to return to said operative position,

whereby, when said clutch is actuated and said armature engages and rotates with said friction disk, said elastomer layer cushions the shock of engagement armature, said drive plate and armature support disk lobes co rotate to translate power to said shaft, while, concurrently, said elastomer layer disturbs and pulls ambient air toward and into said armature outer face in fan like fashion, thereby cooling said armature.