Vehicle transfer case with dual electrically-actuated magnetic clutches

• US 5,545,103 A
• Filed: 08/01/1994
• Issued: 08/13/1996
• Est. Priority Date: 08/01/1994
• Status: Expired due to Fees

• Current Assignee: Warner Electric Do Brasil LTDA (Regal Rexnord Corp.)
• Original Assignee: Dana Corporation (Dana, Inc.)
• Inventors: Gustin, David C.
• Primary Examiner(s): Marmor, Charles A.
• Assistant Examiner(s): JENSEN, NATHAN
• Application Number:
  US08/283,410
• Time in Patent Office: 743 Days
• Field of Search: 180/248, 180/249, 74/665 GA, 192/35, 192/48.2, 192/48.8, 192/84 C, 192/84 PM, 475/222, 475/223
• US Class Current: 475/223
• CPC Class Codes: B60K 17/3462 with means for changing distribution of torque between front and rear wheels
• CPC Class Codes: Y10T 74/19084 Spur

Abstract

A vehicle drive train transfer case includes a differential with an input and two outputs, a normally disengaged electromagnetic first clutch, and a normally engaged second clutch adapted to be electromagnetically disengaged. When the first and second clutches are disengaged and engaged, respectively, torque is transmitted via the differential to the rear axle of the vehicle without torque being transmitted to the front axles so as to propel the vehicle in a two-wheel drive mode. When both clutches are engaged, the differential is locked so as to cause torque to be transmitted to both the front and rear axles and effect propelling of the vehicle in a conventional four-wheel drive mode. When the first and second clutches are engaged and disengaged, respectively, the differential is unlocked to enable torque to be transmitted to both the front and rear axles in an all-wheel drive mode.

Claims

1. A transfer case for a vehicle having front and rear axles, said transfer case having a rotary input member and having first and second rotary output members, said first output member being connected to rotate one of said axles, said second output member being connected to rotate the other of said axles, a differential having an input connected to be rotated by said input member, having a first output for rotating said first output member and having a second output for rotating said second output member, and first and second selectively operable clutch means for:

(a) causing the outputs of said differential to rotate as a unit and causing the input of said differential to transmit torque to said first output member without transmitting torque to said second output member when said first clutch means is fully disengaged and said second clutch means is fully engaged whereby torque is transmitted only to said first output member to drive only said one axle; and

(b) allowing the outputs of said differential to rotate independently of one another and causing the input of said differential to transmit torque from said input member to both outputs of said differential and to both of said output members when said first clutch is fully engaged and said second clutch is fully disengaged, thereby to drive both of said axles;

said first and second clutch means comprising first and second field shells, respectively, disposed in back-to-back relation, each of said field shells having a selectively energizable electric coil, the coil of said first field shell being operable when energized to effect engagement of said first clutch means, said second field shell including a permanent magnet which normally effects engagement of said second clutch means, the coil of said second field shell being operable when energized to negate said permanent magnet and effect disengagement of said second clutch means.

2. A transfer case as defined in claim 1 in which said clutch means causes the outputs of said differential to rotate as a unit and causes said differential to transfer torque from said input member to both outputs of said differential and to both of said output members when both of clutch means are fully engaged.

3. A transfer case as defined in claim 1 in which said first clutch means comprises a clutch selectively operable to connect said second output of said differential to or disconnect said second output of said differential from said second output member.

4. A transfer case as defined in claim 1 in which said second clutch means comprises a clutch selectively operable to cause the outputs of said differential to rotate as a unit or to allow the outputs of said differential to rotate independently of one another.

5. A transfer case as defined in claim 4 in which said first clutch means comprises a clutch selectively operable to connect said second output of said differential to or disconnect said second output of said differential from said second output member.

6. A transfer case for a vehicle having rear and front axles, said transfer case having a rotary input member and having rear and front rotary output members connected to rotate said rear and front axles, respectively, a differential having an input connected to be rotated by said input member and having first and second outputs, the first output of said differential being connected to rotate said rear output member, first and second selectively engageable clutches comprising first and second field shells respectively, disposed in back-to-back relation, each of said field shells having a selectively energizable electric coil, the coil of said first field shell being operable when energized to effect engagement of said first clutch, said second field shell including a permanent magnet which normally effects engagement of said second clutch, the coil of said second field shell being operable when energized to negate said permanent magnet and effect disengagement of said second clutch, each of said clutches having an input connected to be rotated by the second output of said differential, said first and second clutches having outputs connected to said front rotary output member and to the first output of said differential, respectively, said clutches being operable when said first clutch is fully disengaged and said second clutch is fully engaged to cause the outputs of said differential to rotate as a unit and to cause the input of said differential to transmit torque to the first output of said differential and to said rear output member without transmitting torque to said front output member whereby torque is transmitted only to said rear output member to drive only said rear axle, said clutches being operable when said first clutch is fully engaged and said second clutch is fully disengaged to allow the outputs of said differential to rotate independently of one another and to cause the input of said differential to transfer torque to both outputs of said differential and to both of said output members thereby to drive both of said axles with said differential accommodating torque differences imposed on said output members, and said clutches being operable when both clutches are fully engaged to cause the outputs of said differential to rotate as a unit and cause said differential to transfer torque from said input member of both outputs of said differential and to both of said output members without accommodating torque differences imposed on said output members.