Intermediate shaft dash panel seal

An intermediate shaft seal for installation at an opening in a dash panel of a vehicle remove extra space includes an inner shell, an overmold and a bushing assembly. The bushing assembly includes a pair of bushings and is disposed within the inner shell to rotatably support an intermediate shaft of a steering column of a vehicle. The inner shell includes a rigid base plate and sealing ridges for mounting against a dash panel of a vehicle and providing a seal against water, fumes and dirt intrusion. The overmold engages locking features on the inner shell and forms air gaps therebetween cooperating with the sealing ridges and bushings to establish a sound attenuating structure. The inner shell and the overmold include cooperating sinuous shaped sections allowing angular flexibility of the seal for installation in various model vehicles.

TECHNICAL FIELD 
This invention relates generally to seals for a vehicle. In particular, 
this invention relates to a steering column intermediate shaft seal 
installed at the front of the panel of a vehicle. 
BACKGROUND OF THE INVENTION 
It is well known in the design and manufacture of vehicles to provide seals 
at locations where components pass through the passenger compartment dash 
panel. These seals typically partially support the weight and enhance the 
performance of certain components. These seals also serve to prevent the 
intrusion of dirt fumes and water into the passenger compartment and limit 
the transmission of noise and vibration from the component into the 
passenger compartment. 
One type of dash mounted seal is the steering column intermediate shaft 
seal. A steering column intermediate shaft seal of the prior art is 
generally comprised of a single rubber casting and is installed within a 
hole in the dash panel and secured therein by an integrally molded locking 
feature. The seal of the prior art includes a single plastic bushing 
disposed therein for rotatably supporting an intermediate shaft of a 
steering column. 
An intermediate shaft is typically mounted to other shafts comprising a 
steering column between a body mounted upper shaft and a chassis mounted 
steering gear and is routed through the dash mounted seal. The position of 
the steering gear in relation to the dash seal is typically different for 
different model vehicles and as such each vehicle model has a unique dash 
mounted seal. The seal prevents moisture and particle intrusion into the 
passenger compartment by employing compliable sealing features both at the 
intermediate shaft and at the dash opening. The sealing features, together 
with the compliant rubber material itself, also serve to reduce the amount 
of noise and vibration transmitted from the engine compartment to the 
passenger compartment. The bushing disposed within the seal and bellows 
features on the seal further provide low rotary friction support for the 
rotation of the intermediate shaft during operation of the steering 
column. 
SUMMARY OF THE INVENTION 
This invention offers advantages and alternatives over the prior art by 
providing a steering column intermediate shaft to dash panel seal which 
combines a high level of intrusion protection, low rotary friction, and a 
high level of noise abatement. 
An intermediate shaft seal of the present invention includes a bushing 
assembly disposed within a compliant inner shell for rotatably supporting 
the intermediate shaft. The bushing assembly includes a pair of low 
friction bushings receiving the intermediate shaft and providing a low 
friction rotation surface and a seal. 
The inner shell further includes an interface surface having sealing ridges 
and mounting holes for installation on studs protruding from the dash 
panel. Once installed the sealing ridges are compressed against the dash 
panel and provide a seal for intrusion protection against water, fumes and 
dirt. The sealing ridges further provide a measure of sound attenuation. 
The inner shell is covered by an overmold comprised of a compliant rubber 
material. 
The inner shell and overmold have cooperating locking features molded 
therein. With the overmold installed on the inner shell an air gap is 
formed therebetween providing a high level of noise abatement. In 
addition, the inner shell and overmold have sinuous shaped sections which 
cooperate with each other to provide angular articulation of the seal for 
installation in various model vehicles. 
The above discussed and other features and advantages of the present 
invention will be appreciated and understood by those skilled in the art 
from the following detailed description and drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1 there is shown a steering column assembly, generally 
designated as 1, including steering gear 2 mounted to frame 3 and 
connected to lower steering shaft 4 by lower universal joint 5. 
Intermediate shaft 6 is connected to lower shaft 4 by coupling 7 and 
passes through intermediate shaft dash seal 8 mounted to dash panel 9. 
Intermediate shaft 6 includes flex coupling 10 mounted to universal 
connector 11 and upper shaft 12 extending to a steering wheel (not shown). 
Intermediate shaft dash seal 8 is mounted to dash panel 9 at interface 
surface 13 on studs 14, 15, 16 and secured by nuts 17, 18, 19. 
Referring to FIG. 2 inner shell 29 and overmold 30 of intermediate shaft 
seal 8 are generally comprised of a compliant rubber material. Locking 
blade 31 of overmold 30 engages locking groove 32 of inner shell 29 and 
annular tongue 33 of the inner shell engages annular groove 34 of the 
overmold to secure the inner and outer shells together. Inner shell 13 
includes a rigid base plate 35, advantageously comprised of metal for 
example, integrally positioned therein providing a rigid mounting surface 
at interface surface 13, and includes mounting holes 36-38 as best shown 
in FIG. 3. Inner shell further includes integrally molded sealing ridges 
39, 40 on interface surface 13 and sealing rings 41-43 located 
concentrically about access holes 44-46 and mounting holes 36-38. Inner 
shell 29 includes a sinuous shaped bellows 47 mating with a sinuous shaped 
bellows 48 positioned on overmold 30 as best shown in FIG. 2. 
Intermediate shaft dash seal 8 further includes a bushing assembly, 
generally referred to as 50, and best shown in FIG. 2. Bushing assembly 50 
includes bushing tube 51 advantageously comprised of a molded plastic 
material and having a pair of bushings 52, 53 disposed therein. Bushings 
52, 53 are comprised of a low friction material and include bearing edges 
54, 55 and are secured to bushing tube 51 at lands 56, 57 by a suitable 
adhesive as is known. In an embodiment of the present invention inner 
shell 29 is molded around bushing assembly 50, as well as base plate 35, 
encapsulating them therein. 
Noise is generated within an engine compartment side generally referred to 
as 60 in FIG. 1, of dash panel 9, and it is advantageous to attenuate the 
transmission of that noise to a passenger compartment side, generally 
referred to as 61. In an embodiment of the present invention overmold 30 
functions together with air gaps 58, 59, and sealing ridges 39, 40 and 
sealing rings 41-43, as best shown in FIG. 2, to attenuate this noise 
transmission. In operation, sealing ridges 39, 40 and sealing rings 41-43 
of intermediate shaft seal 8 are compressed against dash panel 9 by virtue 
of the clamping forces provided by nuts 17-19 threadably engaging the seal 
onto studs 14-16. Attenuation levels for an embodiment is shown, by way of 
example only, in FIG. 4 where sound transmission loss in Db on the 
vertical axis is plotted against certain frequencies in kHz, for a 1/3 
octal, considered meaningful in the art and is represented by line 62. The 
sound attenuation, for the example shown, ranges from about 14 Db at 1 kHz 
to about 40 Db at 9 kHz. 
It will be appreciated that, when compressed against dash panel 9, sealing 
ridges 39, 40 and sealing rings 41-43 of intermediate shaft seal 8 further 
function to prevent water, fumes and dirt intrusion from engine 
compartment side 60 to passenger compartment side 61. It will also be 
appreciated that mounting holes 36-38 engage studs 14-16 and with the 
addition of nuts 17-19 threadably engaged on the studs, seal 8 is quickly 
and easily installed and secured at dash panel 9. With seal 8 so mounted 
on dash panel 9 steering column assembly 1 components may subsequently be 
installed without the need for special tools or procedures. 
In operation, intermediate shaft 6 is rotatably installed within 
intermediate shaft seal 8 as best shown in FIG. 2. Intermediate shaft 6 is 
supported by and rotates within bearing edges 54, 55 of bushings 52, 53. 
The low friction material comprising bushings 52, 53 provides a low noise, 
low rotation resistance surface to enhance the performance of steering 
column assembly 1. In addition, bearing edges 54, 55 advantageously 
provide a seal against intermediate shaft 6 to preclude water, fumes and 
dirt intrusion from engine compartment area 60 to passenger compartment 
area 61. 
Another advantage of the present invention is the adaptability of a single 
intermediate shaft dash panel seal 8 configuration to several steering 
column assemblies 1, 1' and 1" as best shown in FIG. 1. As described 
hereinabove, steering gear 2 is mounted to frame 3 and steering column 
assembly 1 extends between the steering gear and dash panel 9. For a given 
vehicle (not shown) there may be several different models each having 
different frame 3, 3', 3" and steering gear 2', 2" locations relative to 
dash panel 9. The compliance of the material comprising inner shell 29 and 
overmold 30 combined with bellows 47, 48 forms a flexible portion allowing 
for the acceptance and axial alignment of intermediate shafts 1, 1', 1" 
within the same seal 8 by articulation through angles represented by lines 
63-65. Shaft 6 remains aligned between dash panel opening 66 and steering 
gear 2. Shaft 6 further remains rotatably supported within bushing 
assembly 50 between angles 63 and 65 allowing for low noise and low 
friction rotation of steering column assemblies 1, 1', 1" while 
maintaining noise attenuation and intrusion resistance of the intermediate 
shaft seal 8. 
It will be understood that a person skilled in the art may make 
modifications to the preferred embodiments shown herein within the scope 
and intent of the claims. While the present invention has been described 
as carried out in a specific embodiment thereof, it is not intended to be 
limited thereby but is intended to cover the invention broadly within the 
scope and spirit of the claims.