Integrated transmission control system

An integrated solenoid circuit system for a motor vehicle transmission, and a method of forming the same. The system comprises a housing including a solenoid subhousing and a transmission range sensor (TRS) subhousing. The system also includes a solenoid sensor operatively located in the solenoid subhousing for sensing activation of transmission solenoids. The plurality of transmission sensors is operatively positioned in the transmission range sensor subhousing for communicating transmission states sensed by the solenoid sensor to the controller. A manifold is operatively mounted in the solenoid subhousing for energizing system components. A transmission sensor circuit operatively connects a plurality of transmission sensors to the manifold for selectively activating each of the plurality of transmission sensors in response to a sensed transmission state. The system integrates the transmission sensors, the manifold and the transmission sensor circuit into a single piece construction.

BACKGROUND OF THE INVENTION 
Conventional transmission control systems typically include a plurality of 
solenoid actuated valves for controlling various transmission hydraulic 
fluid pressures in response to particular transmission conditions. Each of 
the solenoids include a terminal that, when energized, actuates an 
assembly pin that communicates the transmission condition to a 
transmission controller, as is generally disclosed in U.S. patent 
application Ser. No. 4,893,652 to Nogle, et al, assigned to Chrysler 
Motors Corporation and incorporated herein by reference. The selective 
actuation of the pins indicate to the controller the present transmission 
state, such as park, reverse, neutral or drive modes. The controller 
processes this information for transmission control purposes as is well 
known in the art. 
While the above transmission control systems have desirable performance 
characteristics, there is still room for further improvement in the art. 
In particular, the components required for realization of the system are 
typically discrete components which are interconnected through seals and 
connectors. The seals and connectors add to overall transmission control 
system expense and assembly requirements. In addition, each of the 
components requires separate insulation from the transmission housing. 
Therefore, it is an object of the present invention to provide an 
integrated transmission control system that minimizes the number of system 
components required for system assembly and operation. 
It is a further object of the present invention to provide a glass filled 
polyester overmolded transmission range sensor circuit and subhousing 
integrally attached to a solenoid subhousing and being electrically 
insulated from a transmission housing to which both subhousings are 
mounted. 
SUMMARY OF THE INVENTION 
The present invention provides an integrated transmission control system 
that combines a plurality of heretofore separate transmission control 
system components into a single piece construction. The system includes a 
glass filled polyester overmolded circuit that houses a plurality of 
solenoid circuits, pressure switches, resistors, a thermistor and 
transmission range sensor components. By combining the transmission 
control system components into a single piece assembly, system cost, 
assembly and components required for system implementation are reduced. 
In particular, the present invention provides an integrated solenoid 
circuit assembly for a motor vehicle transmission comprising a housing 
including a transmission connector subhousing and a transmission range 
sensor (TRS) subhousing. The system also includes solenoid sensing means 
operatively located in the transmission connector subhousing for sensing 
activation of transmission solenoids. A plurality of transmission sensors 
is operatively positioned in the transmission range sensor subhousing for 
communicating transmission states sensed by the solenoid sensing means to 
a controller. A manifold is operatively mounted in the transmission 
connector subhousing for selectively energizing system components. A 
transmission sensor circuit operatively connects the transmission sensors 
to the manifold for selective activation of each of the transmission 
sensors in response to a particular sensed transmission state. The system 
integrates the transmission sensors, and the transmission sensor circuit 
into a single piece construction.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1, a cross-sectional view of a motor vehicle manifold 
assembly is shown generally at 10. The manifold assembly 10 includes a 
solenoid housing 12 affixed to a solenoid valve body 14. The solenoid 
housing 12 communicates with the valve body 14 through a plastic filter 
plate 16 that filters particulates out of hydraulic fluid passing through 
the filter plate 16. The valve body 14 in turn is operatively associated 
with an engine transmission; shown generally at 18, as is well known in 
the art. 
As shown in FIG. 1, an integrated solenoid circuit overmold assembly 20 
according to a preferred embodiment of the present invention is attached 
to the solenoid housing 12. The assembly 20, shown clearly in FIG. 2 
integrates a plurality of transmission control system components into a 
single insulated housing 22, thereby eliminating the need for additional 
components such as seals and connectors typically required when the system 
is configured with separately mounted components. The assembly housing 22 
is preferably formed from glass filled polyester. However, any 
non-conductive insulating material may be used to form the housing 22. A 
snap connector 24 snaps into a valve (not shown) that controls the supply 
pressure to the automatic transmission fluid, indicated generally at arrow 
25, as is well known in the art. Alternatively, a valve energization 
circuit to control supply pressure to the automatic transmission fluid may 
be used. Additionally, a manifold 26 associated with the assembly 20 
connects the assembly 20 to the automatic transmission 18 in a manner well 
known in the art, to energize the assembly components, as will be 
described in more detail below. 
Referring again to the solenoid housing 12, shown in FIG. 1, the solenoid 
housing 12 includes a plurality of ball and plunger combinations, such as 
that shown at 40, for selectively controlling the flow of the hydraulic 
fluid 25 through the housing 12. The ball and plunger combination 40 is 
operatively associated with a pin 46 press fit into an armature 50. The 
armature 50 controls axial movement of the ball and plunger combination 
40, and thus flow of hydraulic fluid 25 through an inlet port 52 and into 
the hydraulic fluid passage 54. The armature 50 is controlled in turn by 
selective energization of a solenoid, such as that shown at 56, which 
includes a solenoid terminal 58. 
It should be appreciated that the operation of all solenoid/plunger/ball 
combinations housed in the solenoid housing 12 shown in FIG. 1, are 
substantially identical in structure and function to the specifically 
referenced components described above. The structure and function of the 
components within the solenoid housing 12 is described generally in U.S. 
Pat. No. 4,893,652 to Nogle, et al, which has been incorporated by 
reference. 
Referring again to FIG. 2, the integrated solenoid circuit assembly 20 
according to the present invention is shown in more detail. The assembly 
20 includes an electronic circuit 60, which is preferably fabricated from 
beryllium copper, molded into the insulator assembly housing 22 through an 
overmolding process described in more detail below. The housing 22 
includes two main subhousings: a solenoid subhousing 62 and a transmission 
range sensor (TRS) subhousing 64. The circuit 60 extends through both 
subhousings 62 and 64 and is configured to include angled portions 65a, 
65b separated by a substantially non-angled portion 65c in the TRS 
subhousing 64 for purposes described below. The structure of each of the 
subhousings 62 and 64 will be described now in more detail. 
As shown in FIGS. 3 and 4, the solenoid subhousing 62 includes a portion of 
the circuit 60, shown generally at 66, that electrically connects solenoid 
terminals 58 with the manifold 26. Through this connection, the solenoids, 
such at that shown in 56, are energized through the manifold. The solenoid 
62 subhousing also houses pressure switches, such as the pressure switch 
71, that function to indicate particular transmission conditions in a 
manner well known in the art. The subhousing 62 also houses a thermistor 
72 that monitors transmission fluid temperature for a controller 74 for 
transmission control purposes, as is well known in the art. Additionally, 
the subhousing 62 includes resistors, such as the resistor 76, for 
reducing current level input to the manifold from the solenoids 56. The 
subhousing 62 additionally includes a plurality of M slots 79 through 
which the solenoid terminals 58 extend and electrically contact the 
circuit tracks 79a of the assembly circuit, 60 (see FIG. 3) such that, 
when a particular solenoid is energized, the manifold conveys a signal 
from the solenoid terminal to components in the TRS subhousing 64. The 
solenoid subhousing 62 additionally includes a plurality of screw openings 
or apertures, such as that shown at 80, for connecting the subhousing 62 
to the solenoid valve body 14. 
As shown in FIG. 2, the TRS subhousing 64 is secured to the valve body 14, 
via a positioning pin 81 affixed to a TRS subhousing neck 82 and fitted 
into a cooperating bore (not shown) in the valve body 14. As will be 
described in more detail below, the TRS subhousing 64 includes a plurality 
of solenoid indicator pins 84a-e housed within pin cylinders 86 formed in 
the TRS subhousing neck 82, as shown in FIG. 5. The pins 84a-e sense the 
vehicle transmission mode (park, reverse, neutral, drive) and are 
selectively actuated into contact with the conductive contact 87a-e in 
cooperating grooves 88a-e in a sliding plate 90. The pin 84a includes a 
washer/retainer assembly 85 that, when in contact with the circuit track 
100, completes a circuit that turns on a vehicle reverse light (not 
shown). The sliding plate 90, which is operatively positioned below the 
pins 84a-e and shown in detail in FIG. 6, signals the present transmission 
state to the controller 74 upon one or more of the pins electrically 
contacting its corresponding conductive contact. 
Referring in more detail to FIGS. 3-5, the structure of the TRS subhousing 
64 will be described in more detail. The TRS circuit portion 83 is formed 
in two segments 98, 99. The first segment 98 includes a circuit track 100 
that connect the transmission reverse mode sensor pin 84a to the manifold. 
The circuit track 100, in combination with spring 102a positioned around 
the pin 84a, selectively actuate the pin 84a into contact with the 
conductive groove 87a in the sliding plate 90 (see FIG. 6) upon shifting 
of the automatic transmission into a reverse mode of operation. The 
contact of the pin 84a with the groove 87a also actuates a vehicle reverse 
light through the washer/retainer assembly 85). Also, a leaf spring 104 
acts as a grounding circuit to allow the vehicle to be started in only 
park or neutral modes by providing an alternate manifold return path for 
high current flowing through the plunger 84a. 
The second segment 99 includes circuit tracks 106 which are formed to 
connect the pins 84b-e which are biased to a normally open position by the 
springs 102b-e with the manifold to signal the occurrence of a shift of 
the transmission into other transmission modes, such as park, neutral and 
drive modes upon energization of the solenoids corresponding to the 
particular transmission mode. In addition, the TRS subhousing 64 includes 
a plurality of circuit rivets 112 for attaching the circuit not overmolded 
into the TRS subhousing 64. 
It should be appreciated at this point that the numerous components housed 
within the two subhousings 62, 64 which have in the past been assembled as 
a plurality of discrete components, have been integrated in the present 
invention into a single piece construction. The integrated single piece 
construction reduces overall system assembly and cost requirements and the 
number of components required to fabricate the system. 
Referring now to the flow diagram at 128 in FIG. 7 and to FIGS. 2, 3 a 
preferred method of fabricating the solenoid circuit assembly 20 of the 
present invention will now be described. At step 130, the circuit 60 shown 
in FIG. 3 is fabricated. At step 132, the circuit 60 is stamped into a 
configuration having a profile such as that shown in phantom in FIG. 2. In 
particular, the circuit 60 is stamped to form the segment of the circuit 
65a at a 45.degree. downward angle in the neck of the TRS subhousing 64 
for a predetermined length. The non-angled segment of the circuit 65c 
extends outwardly from the angled segment. The segment 65a of the circuit 
65b is also configured at an upward angle of preferably about 45.degree. 
with respect to the non-angled segment 65c. The circuit 60 then extends 
through the TRS subhousing neck 82 to the points of connection with the 
pins 84a-e. The circuit 60 is formed in this manner to provide proper 
spacing for loading of the springs 102a-e and pins or plungers 84a-e. 
At step 134, the housing 22 is overmolded onto the circuit 60, thereby 
electrically insulating the circuit 60 and providing a base for mounting 
the circuit 60 to the solenoid housing 12. After the housing 22 is 
overmolded onto the circuit 60, the additional circuit track 100 for the 
reverse mode sensor pin 84a is riveted to the overmolded circuit at step 
136. Alternatively, these additional circuit tracks may be soldered or 
welded onto the circuit tracks after the housing overmolding process. At 
step 137, pins 84a-e and springs 102a-e are inserted within pin cylinders 
86a-e, and positioning pin 81 is affixed to the TRS subhousing 64. 
Referring particularly to reverse pin 84a, the washer/retainer assembly 85 
is pressed onto the pin 84a, the spring 102a is dropped into the cylinder 
86, the pin 84a is inserted within the cylinder 86, and the circuit track 
100 is electrically connected as described above. At step 138, after the 
additional circuit track 100 is added, the system components, such as 
pressure switch components, resistors, the thermistor, are added to the 
housing 22 in electrical connection with the circuit 60 to complete the 
system combination. 
As can be appreciated from the foregoing description, the solenoid circuit 
assembly 20 of the present invention is integrated into a single housing 
22 for mounting and installation into a motor vehicle transmission for 
transmission control purposes. The assembly housing 22, by being 
overmolded over the assembly circuit 60, insulates the circuit 60 as well 
as other system components. At the same time, the assembly 20 of the 
present invention reduces the number of components, and associated cost 
and assembly requirements, associated with like non-integrated motor 
vehicle transmission control systems. 
While the above detailed description describes the preferred embodiment of 
the present invention, the invention is susceptible to modification, 
variation and alteration without deviating from the scope and fair meaning 
of the subjoined claims.