Electromagnetic clutch

• US 5,141,090 A
• Filed: 09/25/1991
• Issued: 08/25/1992
• Est. Priority Date: 09/25/1991
• Status: Expired due to Fees

• Current Assignee: Ogura Corp. (Michigan) (Ogura Clutch Company Limited)
• Original Assignee: Ogura Corp. (Michigan) (Ogura Clutch Company Limited)
• Inventors: Trojan, William B.
• Primary Examiner(s): Bonck, Rodney H.
• Application Number:
  US07/765,444
• Time in Patent Office: 335 Days
• Field of Search: 192/84 C, 192/110 R, 192/111 B, 192/84 B
• US Class Current: 192/84.5
• CPC Class Codes: F16D 1/12 allowing adjustment of the parts about the axis during motion F16D3/10
• 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 10 for transmitting torque includes a field coil assembly 16, a rotor assembly 18 and an armature assembly 20. The field coil assembly 16 includes a toroidal electromagnetic coil 22. The rotor assembly includes a tubular portion 42 mounted on a bearing 36, a ring-shaped section 52 with an attraction surface 54, an outer drum-shaped flange 56 and a drive ring 60. The armature assembly 20 includes an armature hub 62, rubber stops 70, ring-shaped armature 74 and spring steel connecting members 72 connecting the armature to the armature hub. The armature hub 62 includes a central hub 64 with a bore 66 and a stopper plate 68. The bore 66 receives a splined shaft 14 and an air gap adjustment screw 88. A shaft contact surface 94 on the air gap adjustment screw 88 contacts the forward end 96 of a splined shaft 14. The position of the armature hub 62 on the splined shaft 14 and of the armature 74 relative to the attraction surface 54 is changed by rotating the air gap adjustment screw 88 relative to the central hub 64. A plate 106 locks the air gap adjustment screw 88 relative to the central hub 64. A bolt 101 secures the armature assembly 20 to the splined shaft. The armature assembly 20 can be removed from the splined shaft 14 by removing the bolt 101 and screwing a larger bolt into the threaded bore 102.

Claims

1. An electromagnetic clutch for transmitting torque for a drive member to a driven member including a hub assembly with a central hub, a bore through the central hub adapted to receive a shaft, a threaded section in the bore, an air gap adjustment screw with a threaded portion screwed into the threaded section of the bore, a shaft contact surface on the air gap adjustment screw adapted to contact said shaft and fix the axial position of the central hub relative to said shaft, securing means for securing the hub assembly to said shaft wherein the air gap adjustment screw includes a threaded bore adapted to receive a bolt that can contact the axial end surface of said shaft and force said shaft from the bore in the central hub.

2. The electromagnetic clutch of claim 1 including a locking means for preventing rotation of the air gap adjustment screw relative to the central hub.

3. An electromagnetic clutch as set forth in claim 2 wherein the locking means is a plate with a surface that engages the air gap adjustment screw and at least one outer edge tooth that engages teeth in the central bore in the central hub.

4. The electromagnetic clutch of claim 1 wherein the shaft contact surface on the air gap adjustment screw is adapted to contact the axial end surface of said shaft.

5. An electromagnetic clutch including a field coil assembly;

a rotor assembly rotatable about a fixed axis and having an attraction surface on the rotor assembly that is in a plane perpendicular to the fixed axis; and

an armature assembly adapted to be mounted on a shaft that is rotatable about the fixed axis, including a hub assembly with a central hub, an armature connected to the hub assembly and axially movable along the fixed axis relative to the central hub, a bore through the central hub which is concentric with the fixed axis, screw threads in the front portion of the bore through the central hub and wherein the rear portion of the bore is adapted to receive an end of said shaft, an air gap adjustment screw with a shaft contact surface screwed into the screw threads in a portion of the bore through the central hub until the air gap adjustment screw is in a position in which the shaft contact surface is engageable with said shaft to fix the axial position of the central hub relative to said shaft and thereby set the maximum space between the armature and the attraction surface on the rotor, a lock member inserted in the front portion of the central bore through the central hub and in engagement with the air gap adjustment screw and the central hub to prevent rotation of the air gap adjustment screw in either direction after the air gap adjustment screw is set in the desired position within the bore through the central hub, and a fastener for securing the hub assembly to said shaft.

6. The electromagnetic clutch of claim 5 wherein the air gap adjustment screw includes a threaded bore adapted to receive a bolt that can contact the axial end surface of said shaft and force said shaft from the bore in the central hub.

7. An electromagnetic clutch as set forth in claim 5 wherein the lock member is a plate with a surface that engages the air gap adjustment screw and at least one outer edge tooth that engages teeth in the central bore in the central hub.

8. An electromagnetic clutch as set forth in claim 7 wherein the air gap adjustment screw includes a threaded bore adapted to receive a bolt that can contact the axial end surface of said shaft and force said shaft from the bore in the central hub.