Plural output differential drive with coaxial shafts

• US 5,435,790 A
• Filed: 07/26/1993
• Issued: 07/25/1995
• Est. Priority Date: 11/18/1991
• Status: Expired due to Fees

• Current Assignee: Aeromover Systems Incorporated
• Original Assignee: Aeromover Systems Incorporated
• Inventors: Kota, Sridhar, Bidare, Srinivas R.
• Primary Examiner(s): Wright, Dirk
• Assistant Examiner(s): TA, KHOI QUANG
• Application Number:
  US08/097,837
• Time in Patent Office: 729 Days
• Field of Search: 475/204-206, 475/219, 475/221, 475/230, 475/248, 475/332
• US Class Current: 475/221
• CPC Class Codes: B60K 17/346 the transfer gear being a differential gear
• CPC Class Codes: F16H 37/0813 with only one input shaft differentials for four wheel drive vehicles B60K17/346
• CPC Class Codes: F16H 48/08 comprising bevel gears
• CPC Class Codes: F16H 48/10 with orbital spur gears
• CPC Class Codes: F16H 48/11 having intermeshing planet gears

Abstract

A plural output differential drive system provides plural outputs that are differentially related to each other. Three or more output shafts are driven from a single input shaft, each output shaft being differentially linked with the other output shafts. The entire differential drive arrangement is contained within a single housing. The output shafts of the plural output differential will transfer power in applications wherein equal distribution of torque is required at three or more outputs. The input shaft may be arranged to be coaxial with the output shafts, or may be at any other angle, including orthogonal thereto. Typical applications include powering three or more live axles on vehicles, providing rotary power for developing equal torques for simultaneously tightening multiple bolts, and generating equal forces on the gripper fingers of robotic hands. In addition, the outputs can be applied to leveling devices where three or more legs must apply equal pressures on a surface. Differential action is made available to each of the tandem wheels of a truck vehicle, in one embodiment of the invention.

Claims

1. A differential drive arrangement of the type having an input for receiving a rotatory input drive, and a plurality of outputs, each for producing a respective rotary output drive in response to the rotatory input drive, the rotary output drives being differentially related to one another, the differential drive arrangement comprising:

a planetary carrier means for receiving the rotatory input drive;

a plurality of planetary gears coupled to said planetary carrier means, said planetary gears being rotatable in a plane of rotation;

a sun gear for meshing with said plurality of planetary gears, said sun gear being rotatable in a plane of rotation that is parallel to that of said planetary gears;

a first output shaft for providing a first one of the rotary output drives, said first output shaft being coupled to said sun gear, and being rotatable about an axis that is orthogonal to said plane of rotation of said sun gear;

a ring gear for meshing with said plurality of planetary gears, said ring gear being arranged to rotate coaxially with said sun gear;

a first bevel sun gear arranged concentrically with said first output shaft and to rotate in a plane of rotation orthogonal to said axis of said first output shaft;

a second output shaft for providing a second one of the rotary output drives, said second output shaft being coupled to said first bevel sun gear, and being coaxial with said first output shaft;

a second bevel sun gear arranged concentrically with said first output shaft and to rotate in a plane of rotation parallel to that of said first bevel sun gear;

a third output shaft for providing a third one of the rotary output drives, said third output shaft being coupled to said second bevel sun gear, and being coaxial with said first output shaft;

a planetary bevel gear for meshing with said first and second sun bevel gears, said planetary bevel gear being arranged to rotate about its own axis in a plane of rotation that is orthogonal to the planes of rotation of said first and second bevel sun gears; and

carrier means affixed to said ring gear for rotating therewith, said carrier means being further coupled to said planetary bevel gear, said planetary bevel gear being revolved about said axis of rotation of said first output shaft in response to the rotation of said ring gear.

2. The differential drive arrangement of claim 1, wherein there is further provided an input shaft for providing the rotatory input drive.

3. The differential drive arrangement of claim 2, wherein there is further provided a single cavity housing having a first end for receiving said input shaft and a second end for accommodating said first, second, and third output shafts.

4. The differential drive arrangement of claim 1, wherein said first, second, and third output shafts are concentric with respect to one another.

5. The differential drive arrangement of claim 1, wherein there is further provided translation means for convening a rotating motion of one of said output shafts into a linear motion.

6. A differential drive arrangement for distributing mechanical energy produced by a drive motor to a plurality of wheels of a vehicle, the plurality of wheels being arranged in at least a first pair of substantially parallel and coaxial wheels, the differential drive arrangement being of the type having an input shaft for receiving a rotatory input from the drive motor, and a plurality of output shafts, each for producing a respective rotary output drive in response to the rotatory input from the drive motor, the rotary output drives being differentially related to one another, the differential drive arrangement comprising:

a first compound planar-meshing planetary gear system having a first major sun gear, a first minor sun gear, and a first compound planetary gear meshing with said first major and minor sun gears;

a second compound planar-meshing planetary gear system having a second major sun gear, a second minor sun gear, and a second compound planetary gear meshing with said second major and minor sun gears;

input coupling means for coupling said first and second compound planetary gears to the input shaft, said input coupling means further forming a carrier housing intermediate of said first and second planar-meshing planetary gear systems, said carrier housing being rotatable in response to the input shaft;

a bevel-meshing planetary gear system having first and second bevel-meshing sun gears arranged concentrically and in parallel with respect to one another, and at least one bevel-meshing planetary gear arranged to mesh with said first and second bevel-meshing sun gears, each of said first and second bevel-meshing sun gears being coupled with a respective one of said first and second minor sun gears;

carrier coupler means for coupling with said bevel-meshing planetary gear and said carrier housing of said input coupling means;

a first pair of output shafts arranged concentrically with respect to one another and extending in a first direction, each of said output shafts being coupled to a respective one of said first major sun gear and said first bevel-meshing sun gear; and

a second pair of output shafts arranged concentrically with respect to one another and extending in a second direction, each of said output shafts being coupled to a respective one of said second major sun gear and said second bevel-meshing sun gear.

7. The differential drive arrangement of claim 6, wherein there are further provided:

first wheel coupling means for coupling at least one of said first pair of output shafts to vehicle; and

second wheel coupling means for coupling at least one of said second pair of output shafts to a wheel on the other side of the vehicle.

8. A plural output differential of the type having a single input shaft, the plural output differential comprising:

at least three differentially related output shafts;

a single housing for substantially enclosing the plural output differential;

at least two carrier arms disposed within the housing and coupled to the single input shaft;

an epicyclic gear train stage having;

at least two planet gears mounted on said carrier arms,

a sun gear for meshing with said planet gears;

said sun gear having internal splines,

a first output shaft engaged with said internal splines of said sun gear and extending out of said single housing, and

a ring gear for meshing with said planet gears;

a carrier arrangement rigidly attached to a said ring gear, said carrier arrangement being freely rotatable about said first output shaft and being mounted on the housing supported on a bearing;

two bevel planet gears contained within said carrier arrangement at diametrically opposite ends thereof and being rotatable on an axis that is orthogonal to that of said first output shaft;

a bearing support cage for rotatably supporting said two bevel planet gears, said bevel planet gears being internally mounted on said bearing support cage, said bearing support cage further being hollow in the direction of said first output shaft so as to allow said first output shaft to pass therethrough;

first and second bevel sun gears for meshing with said two bevel planet gears and arranged to be rotatable about the axis of rotation of said first output shaft, said first and second bevel sun gears being internally splined;

second and third output shafts, said second output shaft being engaged with said internal splines of said first bevel sun gear, and said third output shaft being engaged with said internal splines of said second bevel sun gear, said first, second, and third output shafts being rotatable about a common axis of rotation.

9. The plural output differential of claim 8, wherein there are further provided a plurality of bearings for maintaining said first, second, and third output shafts mutually concentric.