Motor vehicles – Transmission mechanism – Final drive axle movable
Reexamination Certificate
2001-04-25
2002-09-10
Dickson, Paul N. (Department: 3619)
Motor vehicles
Transmission mechanism
Final drive axle movable
C180S312000, C180S357000, C280S124116, C280S124179
Reexamination Certificate
active
06446748
ABSTRACT:
RELATED APPLICATIONS
This application is related to and claims the priority of Japanese Patent Application No. 2000-127,183, which was filed on Apr. 27, 2000, the entire contents of which is hereby expressly incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates mounting arrangements for rear axles of land vehicles. More particularly, the present invention relates to such mounting arrangements in three or four wheel vehicles, such as all terrain vehicles (ATVs).
2. Description of the Related Art
Recreational all terrain vehicles generally comprise a frame that is carried by at least one front wheel and a pair of rear wheels. The rear wheels typically are attached to the frame with a swing arm, which is connected to a rear portion of the frame and which is capable of pivotal movement relative to the frame about a generally horizontal axis. A shock absorber often is disposed between the swing arm and the frame to control movement of the swing arm during operation of the vehicle over rough terrain.
One example of such a swing arm was disclosed in Japanese Patent No. 2535328.
FIG. 1
reproduces
FIG. 1
of that patent. As illustrated, the swing ann
10
generally comprises an elongated neck portion
12
and a bearing carrying portion
14
. A forward end of the elongate neck portion
12
comprises a pivot shaft
16
and a bearing configuration
18
to promote pivotal movement of the swing arm
10
relative to the frame to which the swing arm
10
is attached. A flange
20
is provided along the neck portion
12
. The flange
20
provides a connecting location for a shock absorber or damper.
The bearing carrying portion
14
is connected to the rear end of the neck portion
12
. In the illustrated arrangement, the bearing carrying portion
14
is comprised of a square tube
22
. The square tube
22
generally is welded directly to the neck portion
12
and provides a housing in which an axle
24
of the vehicle is mounted.
Two sets of bearings
26
positioned within a housing having an upper block
28
and a lower block
30
are disposed within the tube
22
. A set of four threaded fasteners
32
, two of which are shown, are used to secure the housing in position within the tube
22
. The threaded fasteners extend through longitudinal slots
34
formed in the top and bottom surfaces of the square tube
22
. Thus, the longitudinal position of the axle
24
can be adjusted forward and backward.
A further threaded fastener
36
extends rearward from the rear of the housing and through the square tube. This threaded fastener
36
receives nuts
38
that can be tightened to pull the axle
24
rearward through the bearing carrying portion
14
such that tension is increased to a chain used to drive the rear axle
24
.
One drawback to this swing arm construction is that the lateral ends of the square tube are not enclosed. Thus, dust, dirt and other debris can easily become lodged in the tube. Not only does this detract from an otherwise clean vehicle, but the dirt can hamper maintenance and increase wear. For instance, if the chain needs to be slacked, then the dirt must be cleared sufficiently from within the tube to allow the bearings and the associated housing to be moved forward within the tube.
Another drawback to this swing arm construction relates to providing tension to the chain. As can be appreciated, the size of the threaded fastener
36
must be fairly substantial to withstand the loads applied when tensioning the chain. At least two conditions necessitate the increased size. First, only a single member is used to apply the initial tension. Second, the single member is receiving a tensile load under most conditions even though the other threaded fasteners are tightened into position.
SUMMARY OF THE INVENTION
Accordingly, an improved swing arm construction is desired whereby the above-noted drawbacks can be overcome. In addition, the improved construction preferably provides simpler manufacture as well as maintenance.
Accordingly, one aspect of the present invention involves a recreational all terrain vehicle comprising a frame assembly with an engine disposed within the frame assembly. The engine is adapted to power an output shaft and a drive pulley is secured to the output shaft. A swing arm is pivotally connected to the frame assembly with a pair of rear wheels being supported by the swing arm. A pivot axis is defined at a location in which the swing arm is pivotally connected to the frame assembly. The swing arm comprises a forward neck portion and a rearward bearing carrying portion. An axle is connected to the pair of rear wheels with the axle being adapted to rotate about an axle rotational axis. The pivot axis and the axle rotational axis are generally parallel. A driven pulley is connected to the axle with a flexible transmitter extending around the drive pulley and the driven pulley. The bearing carrying portion comprises an outer housing secured to the neck portion. The axle extends through a transverse opening extending through a portion of the outer housing. A pair of plates are positioned on lateral sides of the outer housing and at least partially close the transverse opening. A tubular member extends through the transverse opening and is connected to the pair of plates. A first fastener and a second fastener transversely extend between the pair of plates while the first fastener and the second fastener are adapted to secure the pair of plates to the outer housing.
Another aspect of the present invention involves a swing arm for a recreational all terrain vehicle. The swing arm comprises a neck portion and a bearing carrier portion. The neck portion extends partway into the bearing carrier portion and is secured to the bearing carrier portion. The bearing carrier portion comprises an outer housing with the outer housing defining a transverse opening. A first slot and a second slot also extend transversely through the outer housing and are generally parallel to the transverse opening. A first plate is attached to a first lateral side of the outer housing and a second plate is attached to a second lateral side of the outer housing. A first elongated member extends through the first slot and a second elongated member extends through the second slot. The first plate and the second plate substantially cover the transverse opening and are secured to the outer housing by the first elongated member and the second elongated member.
A further aspect of the present invention involves a recreational all terrain vehicle comprising a frame assembly with an engine disposed within the frame assembly. The engine is adapted to power an output shaft with a drive pulley being secured to the output shaft. A swing arm is pivotally connected to the frame assembly. A pair of rear wheels are supported by the swing arm and a pivot axis is defined at a location in which the swing arm is pivotally connected to the frame assembly. The swing arm comprises a forward neck portion and a rearward bearing carrying portion. An axle is connected to the pair of rear wheels with the axle being adapted to rotate about an axle rotational axis. The pivot axis and the axle rotational axis are generally parallel. A driven pulley is connected to the axle with a flexible transmitter extending around the drive pulley and the driven pulley. The neck portion extends partway into the bearing carrying portion and is secured to the bearing carrier portion. The bearing carrying portion comprises an outer housing that defines a transverse opening. A first slot and a second slot also extend transversely through the outer housing and are generally parallel to the transverse opening. The axle extends through the transverse opening. A pair of plates are positioned on opposing lateral sides of the outer housing. A first elongated member and a second elongated member extend through the first slot and the second slot respectively and the pair of plates substantially cover the transverse opening. The pair of plates are secured to the outer housing by the f
Dickson Paul N.
Knobbe Martens Olson & Bear LLP
To Toan C
Yamaha Hatsudoki Kabushiki Kaisha
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