Split gear assembly with one-way roller clutch for controlling backlash in opposed-piston engines

1. A split gear assembly, comprising:

a first gear and a second gear assembled in a close abutting relationship;

a spring mechanism acting between the first and second gears to rotate the first gear relative to the second gear in a first direction; and

a one-way clutch mechanism acting between the first and second gears to prevent rotation of the first gear relative to the second gear in a second direction opposite the first direction;

in which the spring mechanism includes a plurality of compressed first springs disposed in a circular array of respective first spaces between the first gear and the second gear, each compressed first spring having a first end fixed relative to the first gear and a second end fixed relative to the second gear; and

in which the one-way clutch mechanism includes a plurality of clutch units disposed in a circular array of respective second spaces between the first gear and the second gear, each clutch unit including a spring-biased roller that is pressed into engagement with a wedge-shaped portion of a space in response to force applied to the first gear in the second direction.

2. The split gear assembly of claim 1 , in which each spring-biased roller includes a compressed second spring and a cylindrical roller, the compressed second spring having a first end fixed relative to the first gear and a second end contacting the cylindrical roller, and the cylindrical roller is disposed in the wedge-shaped space between a ramped wall portion of the first gear and a flange surface of the second gear.

3. A split gear assembly, comprising:

a first gear and a second gear assembled in a close abutting relationship;

a spring mechanism acting between the first and second gears to rotate the first gear relative to the second gear in a first direction;

a one-way clutch mechanism acting between the first and second gears to prevent rotation of the first gear relative to the second gear in a second direction opposite the first direction; and

a circumferential array of shaped spaces between the first gear and the second gear, in which the spring mechanism includes a plurality of compressed springs disposed in a circular sequence of respective first shaped spaces, and the clutch mechanism includes a plurality of clutch units disposed in a circular sequence of second shaped spaces that are interspersed with the first shaped spaces;

in which each clutch unit includes a spring-biased roller that is pressed into engagement with a wedge-shaped portion of a second space in response to force applied to the first gear in the second direction.

4. A gear train assembly coupling two crankshafts of an opposed-piston engine that are disposed in a parallel, spaced-apart relationship, comprising:

a driving gear coupled to a first crankshaft; and,

a split gear assembly engaged with the driving gear to transfer rotation from the driving gear to the split gear assembly, in which the split gear assembly includes:

a first gear and a second gear assembled in a close abutting relationship;

a spring mechanism that acts to rotate the first gear relative to the second gear in a first direction; and

a one-way clutch mechanism that prevents rotation of the first gear relative to the second gear in a second direction opposite the first direction,

in which the spring mechanism includes a plurality of compressed first springs disposed in a circular array of respective first spaces between the first gear and the second gear, each compressed first spring having a first end fixed relative to the first gear and a second end fixed relative to the second gear; and,

in which the one-way clutch mechanism includes a plurality of clutch units disposed in a circular array of respective second spaces between the first gear and the second gear, each clutch unit including a spring-biased roller that is pressed into engagement with a wedge-shaped portion of a space in response to force applied to the first gear in the second direction.

5. The gear train assembly of claim 4 , in which each spring-biased roller includes a compressed second spring and a cylindrical roller, the compressed second spring having a first end fixed relative to the first gear and a second end contacting the cylindrical roller, and the cylindrical roller is disposed in the wedge-shaped space between a ramped wall portion of the first gear and a flange surface of the second gear.

6. A gear train assembly coupling two crankshafts of an opposed-piston engine that are disposed in a parallel, spaced-apart relationship, comprising:

a driving gear coupled to a first crankshaft; and

a split gear assembly engaged with the driving gear to transfer rotation from the driving gear to the split gear assembly, in which the split gear assembly includes:

a first gear and a second gear assembled in a close abutting relationship;

a spring mechanism that acts to rotate the first gear relative to the second gear in a first direction;

a one-way clutch mechanism that prevents rotation of the first gear relative to the second gear in a second direction opposite the first direction; and

circumferential array of shaped spaces between the first gear and the second gear, in which the spring mechanism includes a plurality of compressed springs disposed in a circular sequence of respective first shaped spaces, and the clutch mechanism includes a plurality of clutch units disposed in a circular sequence of second shaped spaces that are interspersed with the first shaped spaces,

in which each clutch unit includes a spring-biased roller that is pressed into engagement with a wedge-shaped portion of a space in response to force applied to the first gear in the second direction.

7. The gear train assembly of claim 6 , in which each spring-biased roller is disposed in the wedge-shaped space between a ramped wall portion of the first gear and a flange surface of the second gear.

8. A gear train assembly coupling two crankshafts of an opposed-piston engine that are disposed in a parallel, spaced-apart relationship, comprising:

a driving gear coupled to a first crankshaft; and,

a split gear assembly engaged with the driving gear to transfer rotation from the driving gear to the split gear assembly, in which the split gear assembly includes:

a first gear and a second gear assembled in a close abutting relationship;

a spring mechanism that acts to rotate the first gear relative to the second gear in a first direction; and

a one-way clutch mechanism that prevents rotation of the first gear relative to the second gear in a second direction opposite the first direction;

in which the spring mechanism includes a plurality of compressed first springs disposed in a circular array of respective first spaces between the first gear and the second gear, each compressed first spring having a first end fixed relative to the first gear and a second end fixed relative to the second gear; and

in which the driving gear is a first driving gear and the split gear assembly is a first idler gear, further including a second driving gear coupled to a second crankshaft, and a second idler gear engaged with the second driving gear to transfer rotation from the driving gear to the second idler gear.

9. The gear train assembly of claim 8 , wherein the second idler gear includes:

a third gear and a fourth gear assembled in a close abutting relationship;

a spring mechanism that acts to rotate the third gear relative to the fourth gear in a third direction; and

a one-way clutch mechanism that prevents rotation of the third gear relative to the fourth gear in a fourth direction opposite the third direction.