LIGHT RIDING VEHICLE WITH VARIABLE FRICTION DRIVE

• US 20140080670A1
• Filed: 05/31/2011
• Published: 03/20/2014
• Est. Priority Date: 05/31/2011
• Status: Active Grant

• Current Assignee: Husqvarna AB (HUSQVARNA)
• Original Assignee: Husqvarna Consumer Outdoor Products Na Incorporated (HUSQVARNA)
• Inventors: Elder, Matthew, Graham, Brad, Warner, Justin, Canonge, Eric, Rhoades, Lennie D., Hickman, Jeffrey C., Chandler, Darren, Roth, Chris, Pendry, Warren W., Burns, Duncan Jr., Nelson, Rick, Evrard, Alex, Hansen, Jeremy
• Granted Patent: US 9,445,541 B2
• Time in Patent Office: Days
• US Class Current: 477/115
• CPC Class Codes: A01D 34/00 Mowers combined with apparatus performing additional operations while mowing A01D37/00 - A01D41/00, A01D43/00; convertible to apparatus for purposes other than mowing or capable of performing operations other than mowing A01D42/00; Mowing apparatus of harvesters
• CPC Class Codes: A01D 69/06 Gearings
• CPC Class Codes: F16H 15/10 in which the axes of the two members cross or intersect
• CPC Class Codes: F16H 37/0813 with only one input shaft differentials for four wheel drive vehicles B60K17/346
• CPC Class Codes: F16H 61/6649 characterised by the means for controlling the torque transmitting capability of the gearing

Abstract

Riding lawn mowers may utilize friction drives configured with a variable normal force between frictional components. In a riding lawn mower, an internal combustion engine may be coupled to a differential via a friction drive, wherein the friction drive is configured with a variable normal force in order to provide improved power transfer and/or shifting performance.

Claims

1. A riding law mower, comprising an internal combustion engine;

and a differential coupled to the engine via a friction drive, wherein the friction drive comprises;

a friction plate; and

a friction wheel engageable to the friction plate, wherein the friction wheel and friction plate are engaged via a variable normal force.

2. The riding lawn mower of claim 1, wherein the friction drive is configured to transmit at least 150 foot-pounds of torque to the differential while needing no more than 45 pounds of radial force in order to translate the friction wheel in a radial direction with respect to the friction plate.

3. The riding lawn mower of claim 1, wherein the friction drive comprises a torque sensor between the engine and the friction plate.

4. The riding lawn mower of claim 3, wherein the torque sensor is configured to facilitate varying the normal force.

5. The riding lawn mower of claim 4, wherein the variable normal force is between about 0 pounds and about 100 pounds.

6. The riding lawn mower of claim 4, wherein the torque sensor comprises:

an upper helix coupled to a pulley, wherein the pulley is configured to transfer force to a deck drive via a belt; and

a lower helix, wherein the lower helix is engageable to the upper helix to transfer rotational force to the friction plate, and wherein the lower helix is extendable away from the engine to vary the normal force.

7. The riding lawn mower of claim 6, wherein the torque sensor further comprises a compression spring disposed between the upper helix and the lower helix.

8. The riding lawn mower of claim 6, wherein the helix angles of the upper helix and the lower helix are between 25 degrees and 75 degrees.

9. The riding lawn mower of claim 6, wherein the coefficient of friction between the upper helix and the lower helix is between 0.1 and 0.4.

10. The riding lawn mower of claim 1, further comprising a dual-tubular frame coupled to a cutting deck and the engine.

11. The riding law mower of claim 10, wherein the dual-tubular frame is configured to operate in a spring-like manner having a K value of between about 3800 pounds per inch and about 3900 pounds per inch.

12. The riding lawn mower of claim 10, wherein the cutting deck is configured with a sway bar configured to act as a spring responsive to an applied force exceeding 400 pounds.

13. The riding lawn mower of claim 1, wherein the friction drive further comprises a first clutch configured to transfer power to the differential.

14. The riding lawn mower of claim 13, wherein the riding lawn mower further comprises a second clutch configured to activate a brake on the cutting blade.

15. The riding lawn mower of claim 1, wherein power transferred via the friction wheel is coupled to at least one wheel of the riding lawn mower without the power being transferred by a belt or pulley.

16. The riding lawn mower of claim 1, wherein the riding lawn mower is configured as a single belt system.

17-22. -22. (canceled)

23. A drivetrain for outdoor power equipment powered by an internal combustion engine, the drivetrain comprising:

a friction wheel;

a friction plate frictionally engageable with the friction wheel, wherein the friction wheel and friction plate are engaged via a variable normal force; and

a differential coupled to the friction wheel in order to transfer power to at least one drive wheel of the outdoor power equipment.

24. The drivetrain of claim 23, wherein the friction wheel is translatable in a radial direction with respect to the friction plate via radial force of less than 45 pounds while a torque in excess of 150 foot-pounds is transferred between the friction wheel and the friction plate.

25. The drivetrain of claim 23, wherein the drivetrain is configured with only a single belt, and wherein the belt couples the flywheel to a work assembly.

26. The drivetrain of claim 23, further comprising a torque sensor configured to facilitate varying the variable normal force, wherein the torque sensor comprises:

an upper helix coupled to a pulley, wherein the pulley is configured to transfer force to a drive a work assembly via a belt; and

a lower helix, wherein the lower helix is engageable to the upper helix to transfer rotational force to the friction plate, and wherein the lower helix is extendable away from the engine to vary the normal force.