Engine mount for saddle-seat vehicle

An engine mount for a saddle-seat vehicle includes an upper engine mount operatively connected to the engine of the vehicle. The upper engine mount operatively connects the engine to the frame of the vehicle. At least one connector is provided for connecting the engine to the upper engine mount. The upper engine mount permits substantially free vertical movement of the engine relative to the frame. The upper engine mount includes an outer sleeve operatively connected to the frame. The upper engine mount further includes an elastic cushion arranged between the connector and the outer sleeve. The upper engine mount may further include an inner sleeve located within the elastic cushion for passage of the connector therethrough. The upper engine mount further includes a plate bracket operatively connected between the outer sleeve and the frame. The plate bracket may include lightening holes therein for decreasing the weight of the plate bracket while increasing flexibility of the plate bracket. The upper engine mount substantially reduces or eliminates the transmission of engine vibration to the seat and the rider of the vehicle.

DESCRIPTION OF THE BACKGROUND ART 
Various engine mounting arrangements are known in the prior art. For 
example, U.S. Pat. No. 4,535,869 and U.S. application Ser. No. 08/465,332 
based on Japanese document 6-140587 discuss arrangements for mounting an 
engine. While these arrangements will dampen vibration from an engine, 
they can adversely effect the responsiveness of the vehicle. For example, 
when used in an ATV, these mounts can cause a delay from application of 
the accelerator to movement of the vehicle. Therefore, it is desired to 
provide an engine mounting structure which will adequately dampen 
vibration while not adversely effecting responsiveness or drivability of 
the vehicle. 
SUMMARY OF THE INVENTION 
Accordingly, it is a primary object of the present invention to provide an 
engine mount for a saddle-seat vehicle which will satisfactorily hold the 
engine while reducing vibration transferred from the engine to the vehicle 
seat. 
It is a further object of the present invention to provide an engine mount 
for a saddle-seat vehicle which provides for improved responsiveness or 
drivability of the vehicle. 
Yet another object of the present invention is to provide an engine mount 
for a saddle-seat vehicle which has fewer parts than known prior art 
engine mounting arrangements. Such an engine mount would be simpler and 
less expensive to manufacture and maintain. 
A further object of the present invention is to provide an engine mount for 
a saddle-seat vehicle which is not limited in the placement of the engine 
mounting structure. Therefore, great variability can be had in designing 
the vehicle. 
Yet another object of the present invention is to provide an engine mount 
for a saddle-seat vehicle whereby lag time or responsiveness can easily be 
controlled. Therefore, great freedom in selecting the spring rate of the 
mounting structure can be had. 
Still another object of the present invention is to provide an engine mount 
for a saddle-seat vehicle which solves the above-mentioned problems with 
the prior art mounting structures by using a simple design. 
These and other objects of the present invention are fulfilled by an engine 
mount for a saddle-seat vehicle having an upper engine mount operatively 
connected to the engine of the vehicle, the upper engine mount operatively 
connecting the engine to the frame of the vehicle, and at least one 
connector for connecting the engine to the upper engine mount, the upper 
engine mount permitting substantially free vertical movement of the engine 
relative to the frame. 
Further scope of applicability of the present invention will become 
apparent from the detailed description given hereinafter. However, it 
should be understood that the detailed description and specific examples, 
while indicating preferred embodiments of the invention, are given by way 
of illustration only, since various changes and modifications within the 
spirit and scope of the invention will become apparent to those skilled in 
the art from this detailed description.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring in detail to the drawings and with particular reference to FIG. 
1, a saddle-seat vehicle 20 such as an all terrain vehicle, ATV, is shown. 
This saddle-seat vehicle 20 includes a pair of right and left front wheels 
22, 24 and a pair of right and left rear wheels 26, 28 which are 
respectively suspended from front and rear portions of a vehicle frame 30. 
A balloon-type low pressure tire 32 is mounted around each of the front 
wheels 22, 24 and the rear wheels 26, 28. on the upper portion of the 
vehicle frame 30, a steering handle 34, a fuel rank 36, and a saddle-seat 
38 are disposed. The rider sits on the seat 38. It is desired to avoid 
transfer of engine vibration to the seat 38 and rider to therefore provide 
a smoother ride. An engine 40 for driving the rear wheels 26, 28 is 
disposed within the vehicle frame 30. 
A front body cover 42 and a rear body cover 44 are arranged over upper 
portions of the vehicle frame 30. The front body cover 42 and rear body 
cover 44 each include fenders 46 for covering upper portions of the front 
and rear tires 32. Front and rear cargo carriers 48, 50 are arranged over 
the front and rear body covers 42, 44 for allowing cargo to be secured 
thereto. 
It should be appreciated that the foregoing features of the vehicle, such 
as the positioning and type of body cover, the use of cargo carriers, 
etc., could readily be varied. This description of the vehicle is merely 
given to provide an environment in which the vehicle frame can be used and 
is not intended to limit the instant invention. Moreover, it should be 
recognized that the instant invention can not only be applied in all 
terrain vehicles, but could also be utilized in other vehicles, such as 
motorcycles, snowmobiles, three-wheeled vehicles, etc. 
In FIGS. 2 and 3, an engine 40 is shown. It is contemplated that this 
engine 40 does not have a balance shaft so that vibration dampening would 
be very important for the present invention. Of course, the present 
invention can be used with an engine having a balance shaft. 
At the top of the engine 40 is a cylinder head cover 52. An opening 54 is 
provided in the cylinder head cover as indicated in FIG. 4. As best seen 
in FIG. 4, the upper engine mount 56 is connected to the cylinder head 
cover 52 using this opening 54 as will be described in more detail below. 
Apart from the upper engine mount 56, there are two lower engine mounts 58, 
60 as seen in FIG. 3. These lower engine mounts 58, 60 are described in 
more detail in Japanese document 6-140587 for example. In these mounts, 
rubber with a certain hardness is used. This rubber is harder than that in 
the upper engine mount 56. In other words, a stiffer rubber with a high 
spring rate is used in the two lower mounts 58, 60. These engine mounts 
58, 60 must support the weight of the engine 40 and therefore, a rubber 
mounting with high spring dampening is not normally used. 
As indicated in FIG. 7 of the instant application, different rates of 
compression are possible with different types of rubber. In particular, 
FIG. 7 shows a soft rubber s. For such a soft rubber s, the amount of 
displacement or movement of the rubber (mm) has a certain relationship 
with the amount of force (kg) applied thereon. Also in FIG. 7, a hard 
rubber h has a different reaction in response to the amount of force 
applied. With a hard rubber h, less dampening will take place and 
therefore more vibration will be transmitted. 
In the instant invention, it is desired to avoid the transfer of vibration 
from the engine 40 to the seat 38 and the rider. 
In the prior art, a suggested solution has been to use a soft rubber mount 
as an upper engine mount. This arrangement helps to reduce the transfer of 
vibration. However, there is a time lag in operation and response time of 
the vehicle. 
In particular, when the engine in such a prior art arrangement is 
accelerated, it has a tendency to torque or turn. If a soft rubber is used 
in the upper engine mount, then the engine can initially twist before the 
torque is transferred to the rear drive shaft. Therefore, a slight delay 
occurs between the time an operator starts to accelerate the vehicle and 
the time the vehicle actually begins to move. This time delay, or lag, 62 
in the prior art response time p is illustrated in FIG. 6. After a 
predetermined period of time 62, the engine will no longer twist and the 
vehicle will begin to accelerate. This delay 62 in responsiveness 
adversely effects drivability of the vehicle. 
In the instant invention, such a delay 62 is avoided as indicated by 
response time r in FIG. 6. In particular, when the driver accelerates the 
vehicle, it will immediately respond. Of course, there can be some minor 
time delay, but a delay as great as delay 62 indicated in FIG. 6 is 
avoided. 
In the instant invention, the engine 40 moves in many different directions. 
Basically, these directions of movement can be broken into vibration in 
the vertical direction and vibration in the horizontal direction. This is 
especially true because no balance shaft is used in the engine. The rubber 
used in the mounts generally needs to absorb such vibration. In the 
vehicle, vertical vibration creates the greatest problem because the rider 
on the vehicle is more sensitive to this movement. In other words, such 
vertical vibration is directly transferred to the operator in an up and 
down jarring fashion. Due to the weight of the vehicle, engine 40 and 
operator, horizontal vibration is not as great of a problem. Nonetheless, 
this horizontal vibration should also be dampened. 
Similarly to the lower engine mounts disclosed in Japanese document 
6-140587, the instant lower engine mounts 58, 60 are horizontally 
oriented. The upper engine mount 56 in the present invention, however, is 
vertically oriented. Turning to FIGS. 4 and 5, this arrangement will be 
described in more detail. 
FIG. 4 shows a first embodiment of the upper engine mount 56, while FIG. 5 
shows a second embodiment of the upper engine mount 56'. The longitudinal 
axis of the upper engine mount 56 is generally vertical, whereas the 
longitudinal axis of the upper engine mount 56' is slightly inclined 
substantially parallel to the axis of travel of a piston 63 inside of the 
engine 40. Nonetheless, both of these upper engine mounts 56, 56' are 
substantially vertically oriented unlike the prior art designs. The first 
embodiment of the upper engine mount 56 is preferred, and therefore will 
be described in more detail. However, it should be understood that the 
following description is equally applicable to the second embodiment of 
the upper engine mount 56'. 
In both embodiments, there is preferably an inner sleeve 64, an elastic 
cushion 66, and an outer sleeve 68. The inner sleeve is preferably made of 
metal, but any suitable material such as plastic can be used. Similarly, 
the elastic cushion is preferably made of rubber, but any suitable 
resilient material may be used. The outer sleeve 68 is rigidly affixed to 
a plate bracket 70. This plate bracket 70 is attached to the frame 30 and 
will be described in more detail below. 
The inner sleeve 64 and elastic cushion 66 fit inside the outer sleeve 68. 
The elastic cushion 66 has an outer diameter which is slightly larger than 
the inner diameter of the outer sleeve 68. For example, the outer diameter 
of the elastic cushion 66 can be 0.5 mm larger than the inner diameter of 
the outer sleeve 68. This provides for some frictional mounting between 
the elastic cushion 66 and the outer sleeve 68. However, this frictional 
contact is so slight that the elastic cushion 66 is basically freely 
slidable within the outer sleeve 68. In other words, since the friction 
between the elastic cushion 66 and the outer sleeve 68 is relatively low, 
vertical vibration can easily be handled by the instant system. When the 
engine 40 transfers vertical vibration to the elastic cushion 66, the 
elastic cushion 66 can freely move up and downwardly within the outer 
sleeve 68. None of the vertical component of the vibration is transferred 
to the plate bracket 70. Therefore, no vertical vibration is ultimately 
transferred to the seat 38 or the rider. 
The end of the inner sleeve 64 can rest on the cylinder head cover 52. A 
bolt 72 or other connector can pass through the inner sleeve 64 for 
threadable engagement into the opening 54 of the cylinder head cover 52 in 
order to affix the two members together. Alternatively, a stud may be 
fixed to the cylinder head cover 52, and a nut or other fastener engaged 
to the projecting end of the stud after the elastic cushion 66 is placed 
onto the stud. 
Other mounting arrangements are possible. The elastic cushion 66 may be 
utilized inside of the outer sleeve 68 without the use of the inner sleeve 
64. In such an arrangement, the bolt 72 or other connector would pass 
through an aperture 74 in the elastic cushion 66 for threadable engagement 
in the opening 54 in the cylinder head cover 52. The elastic cushion 66 
may be configured such that the bolt 72 freely passes through the aperture 
74 for reciprocal movement of the bolt 72 with respect to the elastic 
cushion 66, or may be configured such that the bolt 72 is fixedly attached 
to the elastic cushion 66. If the bolt 72 is freely moveable within the 
aperture 74 in the elastic cushion 66, the elastic cushion 66 may be 
fixedly connected to the outer sleeve 68. 
Further, the location of attachment of the upper engine mount 56 is not 
limited to the particular position of the cylinder head cover 52 as shown. 
This upper engine mount 56 can be connected to any other location on the 
cylinder head cover 52. For example, in FIG. 2, this upper engine mount 56 
could be moved forwardly or rearwardly. Alternatively, the upper mount 56 
can be mounted to the cylinder head or the cylinder of the engine 40 
itself. Therefore, there is a great degree of freedom in designing the 
engine mounting structure of the present invention. 
While the vertical component of the vibration has been discussed above, the 
upper engine mount 56 will also help to avoid transfer of the horizontal 
component of vibration to the seat 38 and the rider. 
In particular, the outer sleeve 68 is rigidly affixed to the plate bracket 
70. This plate bracket 70 extends between the left and right seat rails 
76, 78, as shown in FIGS. 3-5. The plate bracket 70 is bolted to these 
seat rails 76, 78. The end of the seat rails 76, 78 are flattened into a 
crescent shape and welded to the vehicle frame 30. The seat 38 is 
supported by the seat rails 76, 78. 
In the prior art, it has been conventional to use a pipe or tube instead of 
plate bracket 70. Such a pipe is relatively rigid and therefore easily 
transfers vibration to the seat rails 76, 78. In the instant invention, on 
the other hand, the plate bracket 70 is less rigid and therefore absorbs 
some of the vibration. This plate bracket 70 can be flat as shown in FIGS. 
4 and 5, or can have a curved or bowed shape, as shown in FIGS. 8 and 9. 
In other words, there would be a flat left-hand side for the modified seat 
bracket, an upward curve, a horizontal midsection, a downward curve and 
another flat right-hand side. As shown in FIG. 9, this bell-shaped curved 
arrangement, or arcuate profile, of the modified plate bracket would also 
aid in absorption of vibration in the horizontal direction. Of course, a 
downwardly curved bracket could also be used instead of the just described 
upwardly curved plate bracket. 
Because the upper engine mount 56 is closest to the seat 38, it is good to 
absorb as much vibration as possible through this upper mount. As noted 
above, the vertical vibration component of the engine 40 is readily 
absorbed due to the sliding motion of the elastic cushion 66 relative to 
the outer sleeve 68, or due to the sliding motion of the bolt 72 relative 
to the elastic cushion 66. Due to the shape of the plate bracket 70, the 
horizontal vibration component of vibration can also be better absorbed 
than in the prior art. While the plate bracket 70 is rigid, it is not as 
rigid as a tube or cross pipe as has been used in the prior art. This 
plate bracket 70 can therefore absorb some of the horizontal vibration 
component. 
Moreover, the modified form of the plate bracket (which is a curved or 
bowed shape) can absorb even more of the horizontal vibration component. 
While these plate brackets are more flexible than that used in the prior 
art, they nonetheless are sufficiently rigid to satisfactorily hold the 
engine in position through the upper engine mount 56 connection. Some 
modifications to this plate bracket 70 are shown in FIGS. 8-10. 
The plate bracket 70 can be stepped as shown in FIG. 8, arched as shown in 
FIG. 9, or have an offset outer sleeve 68 as shown in FIG. 10. Many other 
changes for this plate bracket 70 are possible. For example, the plate 
bracket 70 may include lightening holes 80 as shown in FIG. 10 for 
decreasing the weight of the plate bracket 70 while increasing the 
flexibility of the plate bracket 70. 
As noted above, the instant invention improves responsiveness of the 
vehicle. When the engine 40 is accelerated, there will be little or no lag 
time. The weight of the vehicle, the engine torque output and the spring 
rate of the rubber will all contribute to determine the response time. 
Because vertical vibration is not transmitted from the engine 40 to the 
seat 38 through the plate bracket 70 and seat rails 76, 78 only the 
horizontal component needs to be contended with in the upper engine mount 
56. Therefore, a harder rubber can be used than that in the prior art. 
This harder rubber prevents torquing or twisting of the engine upon 
acceleration thereof. Therefore, the engine will not initially limitedly 
rotate before force is applied to the rear drive shaft. 
The spring rate for the rubber used in the upper engine mount 56 can be 
selected to minimize time lag while effectively dampening the horizontal 
vibration component. Because the engine 40 must be supported by the two 
lower engine mounts 58, 60, it is difficult to vary the spring rate of 
these two mountings. However, the upper engine mount 56 can easily be 
reconfigured to vary the spring rate for the rubber used. Therefore, 
different response characteristics can be had with the instant engine 
mounting system. 
In other engine mounting systems such as those described in Japanese 
document 6-140587, different interconnection components were needed 
between the engine mounting structure and the frame. For example, as seen 
in FIG. 2 of Japanese document 6-140587, a bracket is positioned between 
the engine E and the upper rubber mount Mu. Such a bracket can be avoided 
in the instant invention. Therefore, the number of parts in the instant 
design compared to prior engine mounting systems is reduced. This will 
simplify the manufacture of the engine mounting arrangement and will help 
to minimize costs. 
Accordingly, several benefits will are obtained with the engine mounting 
system of the present invention. The system will avoid or reduce lag time 
upon acceleration of the engine 40. Therefore, a better response time is 
had and drivability of the vehicle is improved. 
Also, vibration will be accommodated such that a smoother ride will be 
provided. The vertical vibration component of the engine 40 has little to 
no impact because it is not transferred through the upper engine mount 56, 
the plate bracket 70 and seat rails 76, 78. The plate bracket 70 can also 
help to accommodate the horizontal component of vibration along with the 
elastic cushion 66 of the upper engine mount 56. 
Also, as noted above, brackets used in prior engine mounting systems can be 
avoided. Therefore, manufacture of the instant invention is simplified. 
Fewer assembly steps are required and the total cost of the engine 
mounting system can be reduced. 
There is some control of lag time in the instant invention due to the 
selection of the spring rate for the rubber in the upper engine mount 56. 
There is therefore great freedom in selecting the spring rate of the upper 
engine mount 56 as there is no need to compensate for the vertical 
vibration component through the use of the elastic cushion 66. 
The location of the upper engine mount 56 can also be greatly varied as 
noted above. This upper engine mount 56 can be connected to the cylinder 
head cover 52 as shown, or can be moved around the cylinder head cover 52 
to many different positions. Also, the upper engine mount 56 could 
actually be mounted to the cylinder head or the cylinder. Therefore, there 
is a great degree of freedom in designing the vehicle. 
The plate bracket 70 compensates for the horizontal component of vibration 
as noted above. This flat bracket or the modified form having a bell-shape 
or curved shaped bracket can be used instead of the conventional tube or 
cross pipe. This plate bracket 70 along with the elastic cushion 66 itself 
helps to compensate for the vertical component of vibration and therefore 
provides a smooth ride. 
Although the present invention has been described with reference to the 
specific embodiment, it will be understood that the present invention is 
not limited thereto, and the same may be varied in many ways. For example, 
the engine 40 for driving the rear wheels 26, 28 is preferably a gasoline 
powered engine, but may include other types of internal combustion 
engines, or may alternatively be an electric motor. further, although rear 
wheel drive is shown herein, the present invention can be adapted for 
front wheel drive or all wheel drive, if desired. 
The invention being thus described, it will be obvious that the same may be 
varied in many ways. Such variations are not to be regarded as a departure 
from the spirit and scope of the invention, and all such modifications as 
would be obvious to one skilled in the art are intended to be included 
within the scope of the following claims.