Snowmobile having a gearbox

Patent metadata

Field	Value
Publication number	US-2020408291-A1
Application number	US-202016747114-A
Country	US
Kind code	A1
Filing date	Jan 20, 2020
Priority date	Jun 28, 2019
Publication date	Dec 31, 2020
Grant date	—

Abstract

A snowmobile has a two-stroke engine having an electronic reverse function so that a crankshaft can be selectively rotated in forward and reverse rotation directions. A gearbox has a first shaft coupled to a countershaft, a second shaft extending parallel to the first shaft, first transmission gears mounted to the first shaft and second transmission gears mounted to the second shaft. The first transmission gears are in constant mesh with the second transmission gears to form high and low gear pairings. A shifter is operable for selectively operating the gearbox in one of a high gear, a low gear and a neutral gear. The engine is selectively operable in the forward and reverse rotation directions while the gearbox is operated in at least one of the high gear, the low gear and the neutral gear.

First claim

What is claimed is:

1 . A snowmobile, comprising:
a frame; at least one ski connected to the frame; a rear suspension assembly connected to the frame; a drive track disposed around the rear suspension assembly; a two-stroke internal combustion engine supported by the frame, the engine comprising a crankshaft, the engine having an electronic reverse function for operating the engine in reverse so that the crankshaft can be selectively rotated in a forward rotation direction and a reverse rotation direction; a continuously variable transmission (CVT) operatively connected to the crankshaft, comprising:
a drive pulley operatively connected to the crankshaft;
a driven pulley; and
a transmission belt interconnecting the drive pulley and the driven pulley;
a countershaft connected to the driven pulley of the CVT; a gearbox comprising:
a first shaft coupled to the countershaft;
a second shaft extending parallel to the first shaft;
a plurality of first transmission gears mounted to the first shaft;
a plurality of second transmission gears mounted to the second shaft,
each of the first transmission gears being in constant mesh with a corresponding one of the second transmission gears to form a plurality of gear pairings including a high gear pairing and a low gear pairing,
for each of the high and low gear pairings:
a given one of the first and second transmission gears being in selective free-spin engagement with a corresponding one of the first shaft and the second shaft to which the given one of the first and second transmission gears is mounted,
an other one of first and second transmission gears being in fixed engagement with a corresponding one of the first shaft and the second shaft to which the other one of the first and second transmission gears is mounted; and

a housing enclosing the first and second transmission gears therein and rotatably supporting the first shaft and the second shaft;
a driveshaft coupled to the second shaft of the gearbox, the driveshaft being operatively connected to the drive track to propel the snowmobile; a shifter operable by a user for selectively operating the gearbox in one of a high gear, a low gear and a neutral gear, such that:
when the gearbox operates in the high gear, the shifter engages the given one of the first and second transmission gears corresponding to the high gear paring to cause driving engagement thereof with the corresponding one of the first shaft and the second shaft;
when the gearbox operates in the low gear, the shifter engages the given one of the first and second transmission gears corresponding to the low gear pairing to cause driving engagement thereof with the corresponding one of the first shaft and the second shaft; and
when the gearbox operates in the neutral gear, the shifter is disengaged from the first and second transmission gears so that the given one of the first and second transmission gears of each of the high and low gear pairings remains in free-spin engagement with the corresponding one of the first shaft and the second shaft,
the engine being selectively operable in one of the forward rotation direction and the reverse rotation direction while the gearbox is operated in at least one of the high gear, the low gear and the neutral gear.

2 . The snowmobile of claim 1 , wherein the gearbox further comprises:
a countershaft gear mounted to the countershaft and enclosed within the housing of the gearbox; and a driven gear fixedly mounted to the first shaft, enclosed within the housing of the gearbox, and in rotational engagement with the countershaft gear so that the first shaft is coupled to the countershaft.

3 . The snowmobile of claim 1 , wherein the gearbox further comprises:
a driving sprocket fixedly mounted to the second shaft and enclosed within the housing of the gearbox; an output sprocket fixedly mounted to the driveshaft and enclosed within the housing of the gearbox; and a flexible driving member drivingly connecting the driving sprocket to the output sprocket so as to transmit rotary motion from the second shaft to the driveshaft.

4 . The snowmobile of claim 3 , wherein the flexible driving member is a chain.

5 . The snowmobile of claim 1 , wherein:
the given one of the first and second transmission gears of each of the high and low gear pairings in selective free-spin engagement with a corresponding one of the first shaft and the second shaft is the first transmission gears such that:
the first transmission gears are in selective free-spin engagement with the first shaft; and
the second transmission gears are in fixed engagement with the second shaft.

6 . The snowmobile of claim 5 , wherein the shifter comprises:
a shifter knob movable between a high gear position, a low gear position and a neutral gear position corresponding to the high gear, the low gear and the neutral gear of the gearbox respectively; a dog mounted on the first shaft and slidable along an axis of the first shaft, the dog comprising dog teeth; and a plurality of links interconnecting the dog to the shifter knob, wherein:
each of the first transmission gears has dog teeth matching the dog teeth of the dog;
when the shifter knob is moved to the high gear position, the dog engages the dog teeth of the first transmission gear corresponding to the high gear pairing;
when the shifter knob is moved to the low gear position, the dog engages the dog teeth of the first transmission gear corresponding to the low gear pairing; and
when the shifter knob is moved to the neutral gear position, the dog is disengaged from the first transmission gears.

7 . The snowmobile of claim 6 , wherein, in the neutral gear position of the shifter knob, the dog is mounted on the first shaft between the first transmission gear corresponding to the high gear pairing and the first transmission gear corresponding to the low gear pairing.

8 . The snowmobile of claim 1 , wherein the housing of the gearbox comprises a left housing portion and a right housing portion, the left and right housing portions being affixed to one another.

9 . The snowmobile of claim 1 , wherein:
the first shaft defines a first shaft axis about which the first shaft is rotatable; the second shaft defines a second shaft axis about which the second shaft is rotatable; and the first shaft axis is vertically higher than the second shaft axis.

10 . The snowmobile of claim 9 , wherein the driveshaft defines a driveshaft axis about which the driveshaft is rotatable, the second shaft axis being vertically higher than the driveshaft axis.

11 . The snowmobile of claim 1 , wherein the first transmission gears and the second transmission gears are helical gears.

12 . The snowmobile of claim 1 , wherein the low gear pairing is disposed laterally between the high gear pairing and the CVT.

13 . The snowmobile of claim 2 , wherein the low gear pairing is disposed laterally between the countershaft gear and the high gear pairing.

14 . The snowmobile of claim 2 , wherein the low gear pairing is disposed laterally between the high gear pairing and the driven gear.

15 . The snowmobile of claim 14 , wherein the driven gear is disposed leftwardly of the low gear pairing.

16 . The snowmobile of claim 3 , wherein the driving sprocket is disposed laterally between the low gear pairing and the CVT.

17 . The snowmobile of claim 16 , wherein the low gear pairing is disposed laterally between the high gear pairing and the driving sprocket.

18 . The snowmobile of claim 2 , wherein the gea

Assignees

• Bombardier Recreational Products Inc

Inventors

• Pard Jean-Sebastien
• Pitre Joel
• Nolet Yan

Classifications

• F16H3/089

  all of the meshing gears being supported by a pair of parallel shafts, one being the input shaft and the other the output shaft, there being no countershaft involved · CPC title

• F16H37/021 Primary

  toothed gearing combined with continuously variable friction gearing · CPC title

• F16H2200/0034

  the gear ratios comprising two forward speeds · CPC title

• F16H9/14

  using only one pulley built-up out of adjustable conical parts · CPC title

• F16H63/04

  a single final output mechanism being moved by a single final actuating mechanism · CPC title