Adjustable air gap and method for electromagnetic clutch

• US 4,524,854 A
• Filed: 09/28/1982
• Issued: 06/25/1985
• Est. Priority Date: 09/28/1982
• Status: Expired due to Term

• Current Assignee: Purolator Products N A Incorporated (Meritor, Inc. (Nevada))
• Original Assignee: Facet Enterprises, Inc. (Devon Energy Corporation)
• Inventors: Miller, Donald L.
• Primary Examiner(s): Bonck, Rodney H.
• Assistant Examiner(s): House, David D.
• Application Number:
  US06/425,589
• Time in Patent Office: 1,001 Days
• Field of Search: 192/84 C, 192/110 R, 192/84 B, 192/84 R, 403/259, 403/261, 403/316, 403/320, 29/526 R, 29/426.6, 29/434, 29/256, 411/195, 411/196
• US Class Current: 192/84.5
• CPC Class Codes: F16B 2200/403 Threaded clamping parts
• CPC Class Codes: F16B 2200/69 Redundant disconnection blocking means
• CPC Class Codes: F16D 27/10 with an electromagnet not rotating with a clutching member, i.e. without collecting rings F16D27/004 takes precedence
• CPC Class Codes: F16D 27/14 Details
• CPC Class Codes: Y10T 29/49805 Shaping by direct application of fluent pressure
• CPC Class Codes: Y10T 29/49824 to elastically deform work part or connector
• CPC Class Codes: Y10T 29/4984 Retaining clearance for motion between assembled parts
• CPC Class Codes: Y10T 29/53848 having screw operator

Abstract

A method and apparatus for making an axially adjustable connection between a clutch shaft and an armature assembly to enable axial adjusting movement of the armature plate relative the inner body magnetic pole face to precisely set the air gap spacing through which an electromagnetic coil attracts the armature plate into frictional driving engagement with the inner body pole face. The hub of the armature assembly is placed upon the clutch shaft and a feeler gage is positioned between the pole face and the armature plate to establish the desired air gap spacing. An adjusting nut is threadedly advanced along a thread of the clutch shaft for progressive axial advance in the direction toward the inner body and engages the hub to maintain the armature assembly against air gap increasing movement away from the pole face. A retaining cap fits over the adjusting nut and engages with an offset abutment face on the shaft to retain the adjusting nut against further adjusting rotation in either direction relative the shaft. A plug member is threaded into a recess of the hub and engages with the end of the shaft to maintain the armature assembly against air gap decreasing movement toward the pole face subsequent to removal of the feeler gage. In the event of later disassembly of the electromagnetic clutch for maintenance or repair, the plug member, retaining cap and adjusting nut are removed. The plug member is then threadedly advanced into engagement with the end of the shaft and functions as a wheel puller facilitating disassembly of the armature assembly from the clutch shaft.

Claims

1. An electromagnetic clutch apparatus for torque transmission between an input member and an output member, said electromagnetic clutch comprising:

a first clutch member;

a second clutch member spaced a predetermined distance from said first clutch member defining an air gap spacing therebetween, an armature mounted to one of said clutch members, said armature being axially moveable across said air gap spacing into frictional torque transmitting engagement with the other of said clutch members;

a shaft mounting said one of said clutch members, said shaft further having means drivably interconnecting said one of said clutch members to effect unitary rotation therewith and enable axial adjusting movement of the one of said clutch members on said shaft to obtain a predetermined air gap spacing between said one of said clutch members and the other of said clutch members;

a first helical thread on said shaft;

a second helical thread on said one of said clutch members;

a first nut member threadedly engaged on said first helical thread of said shaft, said first nut member directly engaging said one of said clutch members to adjust said one of said clutch members to an axial position on said shaft establishing said predetermined air gap spacing between said other of said clutch members and said armature of said one of said clutch members; and

a second nut member threadedly engaged on said second thread of said one of said clutch members, said second nut member further being in abutting engagement with said shaft so that said first and second nut members cooperate to act upon said shaft to effectively mount said one of said clutch members against axial movement in a dlrection away from said axial position on said shaft establishing said predetermined air gap spacing between said other of said clutch members and said armature of said one of said clutch member.

2. An electromagnetic clutch for establishing drive between first and second clutch members, comprising:

a ferromagnetic inner body having a radial face drivingly connected to said first clutch member;

a ferromagnetic armature drivingly connected to said second clutch member and having a radial face opposing said inner body radial face;

means mounting said armature and said inner body with said opposing radial faces spaced from one another by a predetermined air gap spacing therebetween, said mounting means having associated biasing means to enable relative axial movement to bring said radial faces into and out of driving engagement;

electromagnetic coil means mounted adjacent said inner body to cause said inner body and said armature to be drawn into driving engagement across said predetermined air gap spacing upon energization;

a shaft member mounting one of said clutch members concentrically with the other clutch member and having a threaded end portion;

a first threaded retainer threadedly advanced onto said threaded end portion of said shaft, said first threaded retainer directly engaging said one clutch member to position said one clutch member axially upon said shaft member to an axial position establishing said predetermined air gap spacing between said said radial faces of said armature and said inner body to retain said one clutch member against axial movement in one direction away from said predetermined air gap spacing;

said one clutch member having a threaded portion surrounding said shaft member; and

a second threaded retainer threadedly advanced onto said threaded portion of said one clutch member, said second threaded retainer further being into abutting engagement with said shaft member to retain said one clutch member against axial movement in the other direction away from said predetermined air gap spacing between said radial faces of said armature and said inner body.

3. An electromagnetic clutch for torque transmission between a first clutch member and a second clutch member, comprising:

a shaft member having an externally threaded end portion and an end face;

a ferromagnetic inner body carried by said first clutch member, said first clutch member having a radial face concentric with said shaft member;

an armature assembly having a hub journalled upon said shaft member, said armature assembly having a threaded bore surrounding said threaded end portion of said shaft member;

an armature plate concentrically juxtaposed with said radial face of said inner body, said armature plate further comprising associated spring means enabling relative axial movement of said armature plate into and out of driving engagement with said inner body radial face;

drive means connecting said hub of said armature assembly with said shaft member for unitary rotation therewith to enable axial adjusting movement of said hub relative said shaft member to establish a predetermined air gap spacing between said inner body radial face and said armature plate;

an adjusting nut threadedly engaged onto said threaded end portion of said shaft member and advanced into direct abutting engagement with said hub to establish an adjusted axial position of said hub upon said shaft member at which said predetermined air gap spacing is obtained between said inner body radial face and said armature plate;

a plug member threadedly engaged into said threaded bore of said hub and advanced into abutting engagement with said end face of said shaft member to block said hub against axial movement upon said shaft member in the direction which would establish said armature plate closer to said inner body radial face than said predetermined air gap spacing therebetween; and

electromagnetic coil means effective to draw said armature plate across said predetermined air gap spacing and into driving engagement with said inner body radial face whereby a drive connection is established between said first and second clutch members.

4. An electromagnetic clutch or torque transmission between a first clutch member and a second clutch member, comprising:

a mounting shaft having an externally threaded end portion, an end face, and an offset abutment;

a ferromagnetic inner body carried by said first clutch member further comprising a radial face concentric with said mounting shaft;

an armature assembly having a hub journalled upon said mounting shaft, said hub comprising a threaded bore surrounding said threaded end portion of said mounting shaft;

an armature plate concentrically juxtaposed with said radial face of said ferromagnetic inner body comprising associated spring means to enable axial movement of said armature plate relative said hub out of driving engagement with said ferromagnetic inner body radial face;

drive means connecting said hub with said mounting shaft for unitary rotation therewith and enabling axial adjusting movement of said hub relative said mounting shaft to establish a predetermined air gap spacing between said ferromagnetic inner body radial face and said armature plate;

an electromagnetic coil means effective to magnetically move said armature plate across said predetermined air gap spacing between said ferromagnetic inner body radial face and said armature plate into driving engagement with said ferromagnetic inner body radial face such that a drive connection between said first and second clutch members is established;

an adjusting nut threadedly engaged onto said threaded end portion of said mounting shaft and advanced into direct abutting engagement to limit air gap increasing movement of said armature plate away from said ferromagnetic inner body radial face;

a retainer cap engaged over said adjusting nut and engaged with the offset abutment of said mounting shaft to retain said adjusting nut against further adjusting rotation relative said mounting shaft; and

a plug member threadedly engaged into said threaded bore of said hub and advanced into abutting engagement with said end face of said mounting shaft to block said hub against axial movement upon said mounting shaft in a direction such as to decrease said air gap.

5. In an electromagnetic clutch, a connection enabling axial adjustment between a threaded clutch shaft and a threaded armature assembly carried by said threaded clutch shaft for rotation therewith to set an air gap spacing between an armature plate and an inner body pole face, comprising:

an adjusting nut threadably advanceable on said threaded clutch shaft and directly abutting with said threaded armature assembly to prevent an increase in said air gap spacing by retaining said threaded armature assembly against axial movement away from said inner body pole face; and

a plug member threadably advanceable relative said threaded armature assembly and having an abutment face engageable with said threaded clutch shaft to prevent a decrease in said air gap spacing by retaining said threaded armature assembly against axial movement toward said inner body pole face.

6. In an electromagnetic clutch, an axia1ly adjustable connection between a threaded clutch shaft and an armature assembly keyed to said threaded clutch shaft for rotation therewith to enable precise setting of an air gap spacing between an armature plate of said threaded armature assembly and an inner body pole face further comprising;

an offset abutment face on said threaded clutch shaft;

an adjusting nut having a face adapted to directly abut with said armature assembly and threadedly engageable with said threaded clutch shaft for progressive axial movement in a direction toward said inner body pole face to establish said armature plate at a predetermined air gap spacing relative said inner body pole face and to maintain said armature assembly against air gap increasing movement axially away from said inner body pole face;

a retaining cap adapted to fit over said adjusting nut and nonrotatably engaging said offset abutment face of said threaded clutch shaft to retain said adjusting nut against further adjusting rotation relative said threaded clutch shaft; and

a plug member threadedly engageable with said armature assembly and having an abutment face engageable with said threaded clutch shaft to retain said armature assembly against air gap decreasing movement toward said inner body pole face.

7. A method for precisely setting the air gap spacing between an inner body pole face and an armature plate carried by an armature assembly keyed upon a threaded clutch shaft for rotation therewith and axial adjusting movement relative thereto, said method comprising the steps of:

placing a feeler gage between said armature plate carried by said armature assembly and said inner body pole face to establish a predetermined air gap spacing to enable positioning of said armature assembly at the corresponding proper axial position upon said threaded clutch shaft;

progressively threading an adjusting nut onto the clutch shaft and into direct abutting engagement with said armature assembly to maintain said armature assembly against air gap increasing axial movement away from said inner body pole face;

progressively threading a plug member into a threaded bore of said armature assembly and into abutting engagement with the end of said threaded clutch shaft to retain said armature assembly against air gap decreasing axial movement toward said inner body pole face; and

removing said feeler gage from between said armature plate and said inner body pole face.

8. A method for disassembly of an electromagnetic clutch having an armature assembly held at a precise air gap spacing away from an inner body pole face by an adjusting nut engaged upon a clutch shaft and abutting said armature assembly to prevent axial movement of said armature assembly away from said inner body pole face and a plug member threadedly engaged within a bore of said armature assembly and directly abutting with an end of said clutch shaft to maintain said armature assembly against axial movement toward said inner body pole face, comprising the steps of:

rotating said plug member to effect its axial movement away from engagement with said end of said clutch shaft and removal from said armature assembly;

rotating said adjusting nut relative said clutch shaft to effect its removal from said clutch shaft; and

reinstalling and progressively rotating said plug member into a hub member for forced axial engagement with said end of said clutch shaft to function as a wheel puller and forceably break any interference fit between said armature assembly and said clutch shaft whereby said armature assembly may be removed from said clutch shaft.