Automotive emission control valve assembly

A valve assembly, preferably an electric exhaust gas recirculation valve, including a housing with an open end and a base end. The base end having a passage that allows exhaust gas flow therethrough by a salve member operated by an electric actuator. A cap is secured to the open end of the housing with a retainer. The retainer having a renovable snapfit engagement with the housing.

FIELD OF INVENTION 
The present invention relates to automotive emission control valves, for 
example, an exhaust gas recirculation (EGR) valve for an internal 
combustion engine. More particularly, the present invention relates to a 
packaging assembly for an electric EGR valve. 
BACKGROUND OF THE INVENTION 
Electric exhaust gas recirculation (EEGR) valves may include a housing with 
an electrical actuator in the housing that operates a valve member to 
allow exhaust gas to flow through a passage provided in a portion of the 
housing. The housing includes an open end that allows for installment of 
the electrical actuator and the valve member. A cap is placed on the open 
end of the housing to close the housing and to secure the electrical 
actuator in a fixed position within the housing. The cap is provided with 
an electrical connection therethrough to operate the electrical actuator. 
In order to secure the cap and housing together, different fastening 
techniques have been employed. 
One method of attaching the cap to the housing is to employ a clinch ring. 
The clinch ring is deformed to a fixedly secured position around an 
outwardly extending flange portion provided on each of the cap and the 
housing. In order to install a clinch ring and secure the cap onto the 
housing, the flange of the housing and the cap must be suitably sized for 
engagement by the clinch ring. Because of the flange provided on each of 
the cap and the housing, the overall packaging size of the EEGR valve is 
increased. Furthermore, because the clinch ring is deformed and secured in 
place around the flanges of the cap and the housing, installation of the 
clinch ring may require many steps, and once the clinch ring is secured in 
place it is difficult to remove. 
An alternative method of securing the cap to the open end of the housing 
provided in an EEGR valve is to deform a portion of the housing itself 
around the cap. For example, a portion of the housing is sized so that it 
can be deformed towards a central axis of the valve assembly, and, thus, 
surround a portion of the cap to hold the cap on the open end of the 
housing. Although the deformed housing securely holds the cap on the 
housing, if, during assembly, the housing deforming process is not carried 
out in the appropriate manner, the housing can be destroyed. In addition, 
deforming the housing around the cap is labor intensive and requires 
accurate manufacturing steps that may increase the overall cost of 
producing the EEGR valve. Furthermore, once the housing is deformed around 
the cap, removal of the cap becomes very difficult without damaging the 
housing. 
SUMMARY OF THE INVENTION 
Accordingly, it would be desirable to provide an EEGR valve that alleviates 
the problems of EEGR valves in the past that employ a clinch ring or a 
deformed housing in order to secure the cap to the housing. 
It would also be desirable to provide an EEGR valve with a packaging 
assembly that allows for securing the cap to the housing with a single 
assembly step. 
It would also be desirable to provide an EEGR valve with a reduced size and 
efficient packaging assembly, yet still provide for assembly in a single 
step. 
It would also be further desirable to provide an EEGR assembly that allows 
for a removable connection between the cap and the housing. The removable 
connection would preferably allow for assembly without specific alignment 
of the removable connection, and further allow for reduced manufacturing 
tolerances of the valve packaging assembly. 
The present invention provides a valve assembly, preferably an EEGR valve 
assembly, including a housing with an open end and a base end having a 
passage. A valve member is disposed within the housing that opens and 
closes the passage. An electric actuator is provided within housing to 
operate the valve member. A cap is provided proximate the open end to 
close the housing. 
In order to secure the cap to the housing, a retainer that surrounds a 
portion of the cap is provided. The retainer includes at least one locking 
tab that engages at least one locking tab receiver provided on the 
housing. In a preferred embodiment, the at least one locking tab and the 
at least one locking tab receiver engage to provide a snap-fit connection. 
The snap fit connection being removable, that is, readily disengaged. 
In a preferred embodiment of the invention, the retainer comprises a snap 
ring having a cylindrical wall with a lip at the first end of the 
cylindrical wall. The lip extends toward a central axis of the cylindrical 
wall. The cylindrical wall is provided with at least one projection 
between the first end and a second end of the cylindrical wall. The at 
least one projection serves as the at least one locking tab that engages 
the at least one locking tab receiver provided on the housing. 
Also, in a further preferred embodiment of the invention, the housing 
comprises a shell attached to a base. The shell comprises an end wall that 
is substantially perpendicular to a longitudinal axis of the shell. The 
longitudinal axis being substantially parallel with a cylindrical wall 
that is connected to the end wall. The cylindrical wall has an open end 
that serves as the open end of the housing. 
Proximate the open end of the cylindrical wall, a flange is provided that 
extends away from the longitudinal axis of the shell. Between the open end 
and the end wall, the cylindrical wall is provided with at least one 
cut-out member extending toward the longitudinal axis. The flange or the 
cut-out member serve as the at least one locking tab receiver that 
removeably engages the at least one locking tab of the retainer. 
By providing the present invention described above, a cap of an EEGR valve 
can be removeably secured to the housing in a manner that requires limited 
manufacturing assembly steps and provides a simple valve packaging 
structure. That is, by providing a packaging component of the EEGR valve 
(i.e. the retainer) that allows for a readily removable snapfit engagement 
connection, the cap of the valve assembly can be secured to the housing in 
a single step assembly process and without regard to precise alignment of 
the valve packaging components during assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1. illustrates a side elevation of the electric exhaust gas 
recirculation (EEGR) valve of the present invention. The EEGR valve 
includes a housing 10, a cap 20, and a retainer 30. The retainer 30 
removeably secures the cap to the housing 10. The retainer 30 provides a 
removable snap engagement with the housing 10. The retainer 30 allows for 
the cap 20 to be securely held on the housing 10 without an extended 
flange on each of the housing 10 and the cap 20, or without deforming a 
portion of the housing 10 around the cap 20. 
Referring to FIG. 2, the housing 10 of the present invention preferably 
includes an open end 12 and a base end 14. The open end 12 is closed by 
cap 20. In a preferred embodiment of the invention, the housing 10 
comprises a shell 40 attached to a base 50 by a plurality of fastening 
devices. 
The fastening devices may include, for example, a plurality of screws 41 as 
illustrated by the screw heads in FIG. 2, however, the shell 40 could be 
secured to base 50 by bolts, rivets, etc., or other suitable fastening 
arrangements such as gluing or welding the shell 40 to base 50. The base 
50 is provided with a plurality of screw receiving holes (not illustrated) 
that align with screw holes 42 in the shell 40. The plurality of screws 
are placed through the screw holes 42 to secure the shell 40 to the base 
50. In order to align the screw holes 42 of the shell 40 and the screw 
receiving holes of the base 50 an alignment pin 43 is employed. An 
alignment pin hole 44 is provided in the shell 40 and an alignment pin 
receiving hole 45 is provided in the base 50. When the shell 40 is placed 
on the base 50, the shell 40 is orientated to align the alignment pin hole 
44 and the alignment pin receiving hole 45 so that the alignment pin 46 
can be placed through the alignment pin hole 44 of shell 40 and engage the 
alignment pin receiving hole 45 in the base 50. 
Shell 40 preferably includes an end wall 46 that is secured to the base 50 
by the plurality of screws 44, and at least one side wall 47 connected to 
end wall 46. In a preferred embodiment, the at least one side wall 47 
comprises a generally cylindrical wall 47a extending upward from the end 
wall 46. As shown in FIG. 5, a longitudinal axis 48 of the shell 40 
extends perpendicular to the end wall 46 and substantially parallel to the 
cylindrical wall 47a that forms the side wall 47. The cylindrical wall 47a 
terminates at an open end 12s of the shell 40. The open end 12s serves as 
the open end 12 of the housing 10. At the open end 12s of the shell 40 and 
at the top of the cylindrical wall 47a, a flange 49, as shown in FIGS. 2, 
5, and 6, extends around the perimeter of the cylindrical wall 47a. The 
flange 49 extends away from the longitudinal axis 48. 
The shell 40 is also provided with a plurality of cut-out members 60a and 
60b that extend toward the longitudinal axis 48. In addition to the 
cut-out members 60a and 60b, the cylindrical wall 47a of the shell 40 is 
provided with a plurality of openings 61 that, in the preferred 
embodiment, are provided approximate the end wall 46. The plurality of 
openings 61, which are approximate the end wall 46, serve as openings that 
allow for cooling of the EEGR valve. 
Either flange 49 or the cut-out member 60a serves as a locking tab receiver 
on the housing 10. More specifically, as shown in FIG. 3A, flange 49 
serves as locking tab receiver 15, while in FIG. 3B, cut-out member 60 
serves as locking tab receiver 15'. That is, the flange 49 or the cut-out 
member 49a form an engagement member that mates with a locking tab 31 that 
is provided on the retainer 30. As shown in FIG. 3A, the first preferred 
embodiment of the invention, locking tab 31 engages flange 49 to secure 
cap 20 to the shell 40 of housing 10. In second preferred-embodiment of 
the invention, as shown in FIG. 3b, locking tab 31 engages cut-out member 
60a to secure the retainer 30 to the shell 40 of housing 10. 
As shown in FIG. 4, the retainer 30 preferably comprises a plurality of 
locking tabs 31 that engage a locking tab receiver 15 or 15' provided on 
housing 10. As discussed above, in the preferred embodiments of the 
invention, the locking tab receiver 15 or 15' comprises either the flange 
49 or the plurality of cut-out members 60a. By engaging either of the 
respective locking tab receivers 15 or 15' the retainer 30 is secured to 
the shell 40. 
The retainer 30 comprises a snap ring having a cylindrical wall 32. The 
cylindrical wall 32 has a first end 33 and second end 34. Between the 
first end 32 and the second end 24, a plurality of projections 31a, 
preferably four but at least two, are provided that serve as locking tabs 
31. 
It should be noted that the quantity of cut-out members 60a may be greater 
than the quantity projections 31a, however, at a minimum the quantity of 
cut-out-members 60a should be equal to the quantity of projections 31a. By 
providing additional cut-out members 60a than projections 31a, engagement 
of the retainer 30 and shell 40 can be even further simplified. That is, 
to secure the cap 20 to the open end 12 of the housing 10, the retainer 30 
can engage the housing 10 at any of the cut-out members 60a, and, thus, 
effectively eliminate the need for precise alignment of the projections 
31a with respective cut-out members 60a. Preferably, there are two cut-out 
members 60a on opposite sides of the housing 10 so that the retainer 30 
can be secured to the housing 10. 
The projections 31a extends towards a central axis 34 of the cylindrical 
wall 32. The projections 31a preferably comprise cut-out members of a 
rectangular shape with one end secured to the cylindrical wall 32. Each 
projection cut-out member is preferably formed by lancing a portion of the 
cylindrical wall 32. 
The snap ring of retainer 30 is also provided with a lip 36 that projects 
toward a longitudinal central axis 35 of the cylindrical wall 32. In the 
preferred embodiment of the invention, the ring comprises a monolithic 
member formed from a sheet of metallic material. That is, the cylindrical 
wall 32 and lip 36 are a continuous structural member. 
The lip 36a engages cap 20 and biases the cap 20 toward the open end 12s of 
the shell 40. Accordingly, the lip 36 serves as a spring member that, in 
addition to the snapfit locking engagement between the locking tab 31 of 
the retainer 30 and locking tab receiver 15 or 15' of the shell 40, serves 
as an additional member that secures the cap 20 to the shell 40 of the 
housing 10. 
The lip 36 serves as a spring member that biases the cap 20 toward the open 
end 12s of the shell 40 because the lip 36 is oblique to the central axis 
35 of the retainer 30, while the cylindrical wall 32 of the retainer 30 is 
substantially parallel with the central axis 35. Because the lip 36 
extends from the first end 33 of the cylindrical wall 32 toward the 
central axis 35 at a non-perpendicular angle (i.e. an oblique angle), when 
the retainer 30 is fit over the cap 20 and the locking tab 31 engages the 
locking tab receiver 15 or 15' of the shell 40, the lip 36 forces the cap 
20 toward the shell 40. 
As discussed above and shown in FIGS. 3A and 3B, the retainer 30 can be 
dimensioned such that the locking tab 31 engages different locking tab 
receivers 15, 15' on the shell 40, for example, either the flange 49 or 
the cutout member 60a of the shell 40. As discussed above, in the first 
preferred embodiment of the invention illustrated in FIGS. 2 and 3a, the 
locking tab 31 of the retainer 30 engages the flange 49. In order to 
insure that the projection 31a of the retainer 30, which serves as the 
locking tab 31, engages the flange 49 in a secure manner and without 
removal from frictional forces that the projection 31a places on flange 
49, the flange 49 is provided with a sharp radius with respect to the 
cylindrical wall 47a. The radius between the cylindrical wall 37a and the 
portion of the flange 49, which extending away from the cylindrical wall 
47a, is configured such that the projection 31a will remain secure to the 
flange 49. That is, the projection 31a will remain substantially in the 
corner 49a of the flange 49 without slipping along the flange 49. For 
example, in a preferred embodiment of the invention, the radius between 
the extending portion of flange 49 and the cylindrical wall 47a is a 
maximum of 0.2 millimeters. 
In addition to serving as the alternative locking tab receiver 15', cut-out 
members 60a provide an additional function for the EEGR valve assembly. 
That is, the cut-out members 60a provide support for the electric actuator 
70. In the preferred embodiment of the invention, the shell 40 is provided 
with a plurality of cut-out members 60b in addition to the plurality of 
cutout members 60b. The cut-out members 60a and 60b, respectively, provide 
a plurality of upper and lower sets of landing pads 61a and 61b that 
secure the electrical actuator 70 within the shell 40. 
The electric actuator 70 includes a stator structure 71 that provides a 
magnetic circuit path, a coil 72 adjacent the stator structure 71, and an 
armature 73 proximate the stator structure 71 that is acted upon by the 
magnetic flux in the magnetic circuit path. The stator structure 71 
includes an upper stator member 71a that is held in place by an upper 
group of Landing pads 61a provided by the upper set of cut-out members 
60a. The stator structure further comprises a lower stator member 71b that 
is held in place by a lower group of landing pads 61b provided by the 
lower set of cut-out members 60b. 
The base 50 of the housing 10 includes a passage 80 that is opened and 
closed by a valve member 90. The valve member 90 includes a valve head 91 
that operates in conjunction with a valve seat 92. The valve head 91 is 
displaced from the valve seat 92 by corresponding movement of the armature 
72 relative to the stator structure 71 of the electric actuator. The 
armature 72 is moved within the upper stator member 71a and the lower 
stator member 71b when a coil 72 is provided with a pulse width modulated 
signal. The upper stator member 71a and the lower stator member 71b are 
axially separated to form an air gap. Preferably a sleeve 71s is provided 
between the stator structure 71 and the armature 72. In order to reduce 
radial forces acting on the armature 72, the inner surface of the upper 
stator member 71a is provided with an undercut 71u that defines a minimum 
air gap between the armature 72 and the upper stator member 71a. 
The cap 20 includes a portion 22 that extends outward to provide an area 
for an electrical connector shell 24. The electrical connector shell 24 
has an electrical connector 26 that extends through the cap 20 to the coil 
72 of the electric actuator 70. 
A shaft 93 extends from the armature 73 to the valve head 91. The shaft 93 
is fixedly secured to the armature 73 by a threaded portion 93a of the 
shaft 93 and a nut 94 that engages the threaded portion 93a of the shaft 
93. The shaft 93 is guided in a central through hole of a bearing 95 
provided between the lower stator member 71b and the valve seat 92. The 
valve seat 92 is disposed within the base 50 of the housing 10. The valve 
head 91 of the valve member 90 is biased toward the valve seat 92 by a 
spring 96 that engages the armature 72 of the electric actuator 70. 
The base end 50 of the housing 10 comprises the passage 80. The passage 80 
includes an entrance 81 that allows engine exhaust gas, from an internal 
combustion engine, to enter the base end 50 for recirculation. The passage 
extends through the base end 50 for conveying engine exhaust gas that has 
entered the passage 80, and an exit 82 at which engine exhaust gas that 
has passed through the passage 80 exits. The valve member 90 is controlled 
by the electric actuator 70 to control the flow of gas through the 
passage. 
In order to assemble the EEGR valve of the present invention, the base end 
50 and the shell 40 are secured together, preferably, as discussed above 
by a plurality of screws 41 with the aid of the alignment pin 44. Then, 
the electric actuator 70 is installed within the shell 40. Once electric 
actuator 70 is installed within the shell 40, the cap 20 is placed 
approximate the open end 12s of the shell 40. In order to secure the cap 
20 to the shell 40, the retainer 30 is placed over the cap 20 and forced 
down such that the retainer 30 surrounds at least a portion of the cap 20, 
and locking tabs 31 of the retainer 30 snap engage the locking tab 
receiver 15 of the housing 10. 
Although the cap 20 is securely held onto the shell 40 by retainer 30, the 
arrangement of the locking tabs 31 in the form of the projections 31a 
extending toward the central axis 35 of the retainer 30 allows for a gap 
85 in the area between cylindrical wall 47a of the shell 40 and the 
cylindrical wall 32 of the retainer 30. This gap 85 allows for 
installation of a tool that can bias the projections 31a away from the 
central axis 35 of the retainer 30. When the projections 31a are biased 
away from the central axis 35, the retainer 30 can be readily removed from 
the shell 40. 
When the EEGR valve of the present invention is completely assembled, the 
longitudinal axis 48 of the shell 40 and the central axis 35 of the 
retainer 30 are coaxial. When the retainer 30 surrounds the shell 40, the 
diameter of cylindrical wall 32 of the retainer 30 and the diameter of the 
cylindrical wall 47a. of the shell 40 have a maximum value of 65 
millimeters. More particularly, the retainer's cylindrical wall 32 has a 
larger diameter than the shell's cylindrical wall 47a, and the retainer's 
cylindrical wall 32 is no greater than 65 millimeters, preferably, 63 
millimeters. Furthermore, the overall length of the assembled EEGR is less 
than 135 millimeters, particularly 132 millimeters. 
Accordingly, the snap engaging retainer 30 of the present invention 
removeably secures the cap 20 to the housing 10. Although, the claimed 
invention has been described with the locking tab being provided on the 
retainer 30 and the locking tab receiver being provided on the shell 40, 
it should be readily understood that the locations of the locking tab and 
the locking tab receiver could be reversed. 
Other embodiments of the present invention will be apparent to those 
skilled in the art upon consideration of the specification disclosed 
herein. It is intended that specification be considered as exemplary only, 
with the true scope and spirit of the invention being indicated by the 
appended claims.