U.S. patent application number 12/046671 was filed with the patent office on 2008-06-26 for closed loop pressure control system and electrically operated pressure control valve with integral pressure sensor and method of making same.
This patent application is currently assigned to EATON CORPORATION. Invention is credited to Harold L. Bowman, Greg E. Ford, Timothy J. Green, Peter M. Jacobsen.
Application Number | 20080148725 12/046671 |
Document ID | / |
Family ID | 35781388 |
Filed Date | 2008-06-26 |
United States Patent
Application |
20080148725 |
Kind Code |
A1 |
Jacobsen; Peter M. ; et
al. |
June 26, 2008 |
CLOSED LOOP PRESSURE CONTROL SYSTEM AND ELECTRICALLY OPERATED
PRESSURE CONTROL VALVE WITH INTEGRAL PRESSURE SENSOR AND METHOD OF
MAKING SAME
Abstract
A solenoid operated valve has a pressure transducer sensing
valve outlet pressure integrally formed in the valve body, such as
by overmolding. Upon connection of the transducer and solenoid to
an electronic controller, the controller generates a valve
energization signal in response to a desired valve pressure output
and the transducer input for providing closed loop control of the
valve outlet pressure. An ASIC may also be integrally formed in the
valve body, such as by overmolding for providing integrated signal
conditioning; and, the optional ASIC, if employed, may also include
the circuitry for the electronic controller for providing a "smart"
pressure control valve.
Inventors: |
Jacobsen; Peter M.; (Oakland
Township, MI) ; Ford; Greg E.; (Detroit, MI) ;
Green; Timothy J.; (Holly, MI) ; Bowman; Harold
L.; (Lapeer, MI) |
Correspondence
Address: |
QUINN LAW GROUP, PLLC
39555 ORCHARD HILL PLACE, SUITE # 520
NOVI
MI
48375
US
|
Assignee: |
EATON CORPORATION
Cleveland
OH
|
Family ID: |
35781388 |
Appl. No.: |
12/046671 |
Filed: |
March 12, 2008 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10960624 |
Oct 7, 2004 |
|
|
|
12046671 |
|
|
|
|
Current U.S.
Class: |
60/459 ;
251/129.01; 251/129.15; 29/890.124; 29/890.127 |
Current CPC
Class: |
F16K 31/0637 20130101;
Y10T 137/8326 20150401; Y10T 137/0396 20150401; Y10T 29/49412
20150115; Y10T 29/49417 20150115; Y10T 137/0318 20150401; Y10T
137/7761 20150401; F16K 31/0665 20130101 |
Class at
Publication: |
60/459 ;
251/129.01; 251/129.15; 29/890.124; 29/890.127 |
International
Class: |
F15B 21/08 20060101
F15B021/08; F16K 31/02 20060101 F16K031/02; B23P 11/00 20060101
B23P011/00; F04B 49/08 20060101 F04B049/08; F15B 13/02 20060101
F15B013/02; F15B 15/00 20060101 F15B015/00 |
Claims
1. An electrically operated valve assembly for use in closed loop
pressure control comprising: (a) an operator effective upon
selective electrical energization to effect movement of an actuator
member associated therewith; (b) a valve body having an inlet, an
outlet, and a valving chamber communicating with said inlet and
outlet; (c) a valve member disposed in said valving chamber and
moveable by said actuator member between a first position
increasing and a second position decreasing fluid pressure
communication between said inlet and outlet; (d) a pressure
transducer integrally formed in the material of said valve body and
substantially enclosed by said valve body, said pressure transducer
communicating with a pressure at said outlet and operable, upon
electrical connection therewith, to provide an electrical signal
indicative of said pressure sensed in said outlet; and (e) a first
terminal operably connecting said operator and said transducer, and
a second terminal configured for external circuit connection
thereto.
2. The valve assembly defined in claim 1, wherein said valve body
is formed by molding.
3. The valve assembly defined in claim 2, wherein said pressure
transducer is overmolded in the material of said valve body.
4. The valve assembly defined in claim 1, wherein said operator
includes a solenoid with a moveable armature.
5. The valve assembly defined in claim 4, wherein said actuator
member is operatively connected to said armature.
6. The valve assembly defined in claim 1, wherein said valve body
is molded of a non-metallic material.
7. The valve assembly defined in claim 1, wherein said valve body
is molded of substantially plastic material.
8. The valve assembly defined in claim 1, wherein said pressure
transducer includes a solid state sensing element.
9. The valve assembly defined in claim 1, further comprising an
ASIC integrally formed in said valve body.
10. The valve assembly defined in claim 1, wherein said pressure
transducer and said first terminal are mounted on a substrate
board.
11. The valve assembly defined in claim 1, wherein said operator is
electrically connected to said first terminal by plug-in connection
to said valve body.
12. The valve assembly defined in claim 1, wherein said transducer
is mounted on a circuit board including an ASIC configured to
provide closed loop control of the valve assembly upon connection
to an electronic controller.
13. The valve assembly defined in claim 1, wherein said electrical
signal from said pressure transducer is configured to produce said
selective electrical energization of said operator.
14. A method of making a valve assembly for closed loop pressure
control comprising: (a) forming a valve body with a valving chamber
communicating with an inlet and outlet; (b) disposing a valve
member in the valving chamber for movement between a position
increasing and a position decreasing fluid pressure communication
between the inlet and outlet; (c) disposing an electrical operator
on the valve body configured to effect said movement of the valve
member upon energization; (d) integrally forming a pressure
transducer in the material of the valve body to substantially
enclose the pressure transducer in the valve body and sensing
pressure at the outlet and providing an electrical indication
thereof, and disposing an electrical terminal on the valve body for
electrical connection thereto.
15. The method defined in claim 14, wherein said forming the valve
body includes molding.
16. The method defined in claim 15, wherein said integrally forming
the pressure transducer includes overmolding the valve body over
the transducer.
17. The method defined in claim 14, wherein said integrally forming
the pressure transducer in the valve body includes mounting a solid
state device on a substrate.
18. The method defined in claim 17, further comprising mounting an
ASIC on the substrate and connecting said pressure transducer to
said ASIC and effecting closed loop control operation of the
valve.
19. The method defined in claim 14, wherein said integrally forming
the pressure transducer includes overmolding a solid state
sensor.
20. The method defined in claim 14, wherein said forming the valve
body includes molding the valve body of nonmetallic material.
21. The method defined in claim 14, wherein said forming the valve
body includes molding the valve body of substantially plastic
material.
22. The method defined in claim 14, wherein said disposing the
electrical operator includes disposing a solenoid.
23. The method defined in claim 14, wherein said integrally forming
a transducer includes integrally forming a piezoelectric
transducer.
24. The method defined in claim 14, wherein said disposing the
electrical operator includes disposing a solenoid with a moveable
armature configured such that moving the armature effects said
valve member movement.
25. The method defined in claim 14, wherein said disposing the
electrical operator includes electrically plug-in connecting the
operator to the valve body.
26. The method defined in claim 14, wherein said forming the valve
body includes forming the valve body of a material selected from
one of polyetheramide and polythalamide material.
27. The method defined in claim 26, wherein said forming the valve
body further includes filling the material with about 10-40% by
volume of glass particles.
28. A closed loop fluid pressure control system comprising: (a) a
fluid pressure operated actuator operative for effecting a function
to be controlled; (b) a source of pressurized fluid; (c) an
electrically operated pressure control valve having a body with an
inlet connected to receive said pressurized fluid and an outlet
connected to said fluid pressure operated actuator; (d) a pressure
transducer integrally formed in said body and substantially
enclosed by said body, said pressure transducer being operative,
upon connection of a circuit thereto, for providing an electrical
indication of the pressure at said outlet; and, (e) an electronic
controller disposed in said circuit to receive said electrical
indication from said pressure transducer and operative in response
thereto to generate and supply an electrical control signal to said
electrically operated pressure control valve for a desired outlet
pressure, thereby providing closed loop pressure control of said
actuator.
29. The system defined in claim 28, wherein said pressure
transducer is mounted on a substrate.
30. The system defined in claim 29, wherein said substrate includes
an ASIC.
31. The system defined in claim 28, wherein said electronic
controller is located remote from said electrically operated
pressure control valve.
32. The system defined in claim 28, wherein said electrically
operated pressure control valve includes a solenoid.
33. The system defined in claim 32, wherein said pressure
transducer is mounted on a substrate including a connector terminal
and said solenoid electrically connects to said terminal in plug-in
arrangement.
34. The system defined in claim 28, further comprising an ASIC
formed integrally in said body.
35. The system defined in claim 34, wherein said ASIC includes said
electronic controller.
36. The system defined in claim 28, wherein said pressure
transducer includes a die mounted on a ceramic ring.
37. An electrically operated fluid pressure control valve capable
of closed loop pressure control upon energization comprising: (a) a
valve body defining an inlet, an outlet and a valving chamber
communicating with said inlet and outlet; (b) a valve member
disposed in said valving chamber and moveable therein between a
position increasing and a position decreasing fluid flow between
said inlet and outlet; (c) an electrical operator associated with
said valve body and operable, upon energization, for effecting the
movement of said valve member; (d) a pressure transducer disposed
in said outlet and configured to sense a pressure at said outlet;
and (e) an electronic controller disposed in a circuit with said
pressure transducer and said electrical operator, wherein said
pressure transducer and said controller are integrally formed in
said valve body and wherein said pressure transducer is
substantially enclosed by said valve body.
38. The valve defined in claim 37, wherein said valve body is
molded of nonmetallic material.
39. A method of making an electrically operated pressure control
valve for closed loop pressure control comprising: (a) forming a
valve body of nonmetallic material with an inlet, outlet and a
valving chamber communicating with said inlet and outlet; (b)
disposing a valve member in said chamber for movement therein to
increase or decrease flow between said inlet and outlet; (c)
disposing an electrical operator in association with said valve
body and, upon energization, effecting said movement of said valve
member; and (d) integrally forming a pressure transducer and an
electronic controller in said nonmetallic material of said valve
body to substantially enclose said pressure transducer in said
valve body and connecting said electronic controller in circuit
with said transducer and said electrical operator.
40. The method defined in claim 39, wherein said integrally forming
an electronic controller includes overmolding an ASIC.
41. The method defined in claim 39, wherein said integrally forming
a pressure transducer and an electronic controller includes
mounting a piezoelectric device and an ASIC on a substrate.
42. The method defined in claim 41, wherein said integrally forming
includes overmolding said piezoelectric device, said ASIC and said
substrate.
43. The method defined in claim 42, wherein said overmolding
includes applying a viscous material and overmolding with a plastic
material.
44. The method defined in claim 39, wherein said disposing an
electrical operator includes disposing a solenoid.
45. The method defined in claim 39, wherein said disposing an
electrical operator includes engaging a solenoid in plug-in
engagement with said valve body.
46. The method defined in claim 39, wherein said integrally forming
a pressure transducer includes mounting a die on a ceramic ring.
Description
CLAIM OF PRIORITY AND CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation Application of U.S.
Non-Provisional patent application Ser. No. 10/960,624, filed on
Oct. 7, 2004, which is hereby incorporated by reference in its
entirety, and to which priority is claimed herein.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to fluid pressure control
systems where it is desired to employ closed loop control utilizing
electrically operated valves, and particularly valves of the type
operated by a solenoid, for providing pressure control of fluid in
a system in response to an electrical signal from an electronic
controller.
[0003] Solenoid operated valves have found widespread application
in systems where it is desired to control fluid pressure to a fluid
pressure actuated device such as pneumatic or hydraulically
pressure actuated valves, pistons or diaphragms. More particularly,
solenoid operated pressure control valves have found widespread use
in automotive applications inasmuch as solenoids have proven to be
cost effective valve operators capable of energization by the low
voltage direct current power supplies typically available on motor
vehicles.
[0004] An example of the aforesaid automotive applications of
solenoid operated pressure control valves is that of utilizing the
solenoid operated valve to control the pressure of the hydraulic
fluid employed for actuating the shift clutches in an automatic
speed change gear set power transmission employed for providing the
traction power for vehicle propulsion.
[0005] Automatic transmission applications of solenoid operated
pressure control valves have heretofore required precise
calibration of the solenoid valve to provide the desired pressure
output for clutch operation in response to the electrical control
signal from the vehicle powertrain controller. In addition, such
applications have required extremely tight tolerances on the
hysteresis of the valve with respect to valve response from
increasing and decreasing electrical control signals. If the valve
has a significant amount of hysteresis, or is not repeatable with
respect to successive signal applications for the same desired
pressure output, the operation of the transmission shift clutches
will be jerky or erratic and thus objectionable to the vehicle
operator.
[0006] The aforesaid problem of accuracy and repeatability of the
actuation of an electrically operated pressure control valve
operating in an open loop control mode, and particularly solenoid
operated valve, irrespective of the application. Thus it has been
desired to improve the accuracy and repeatability of solenoid
operated pressure control valves for all fluid pressure control
applications. Therefore, it has been proposed to use closed loop
control mode of operation of solenoid valves.
[0007] Morever, to simplify the closed-loop system, there is a
desire to provide a way or means of sensing the pressure in the
outlet of a solenoid operated pressure control valve without
separately mounting pressure sensors to the valve or in the
pressure outlet line of the valve and to provide such in an easy to
manufacture and cost effective manner.
BRIEF SUMMARY OF THE INVENTION
[0008] The present invention addresses the above-described problem
and provides closed loop control of an electrically operated system
which uses a fluid pressure actuator for effecting a function to be
controlled. The system may be employed for fluid pressure actuators
operating on either compressible fluid such as air or substantially
incompressible fluids such as hydraulic fluids, water or oil.
[0009] The fluid pressure control is provided by an electrically
operated valve having a valve body with a pressure transducer
integrally formed therein which provides an electrical signal
indicative of the pressure at the valve outlet. An electronic
controller receives an electrical signal from the transducer; and,
in response to an electrical fluid pressure command signal, the
controller generates an electric control signal for operating the
valve, thereby providing closed loop control of the fluid pressure
actuator. The pressure transducer is formed integrally with the
valve body and may be insert cast or overmolded in the valve body.
An optional ASIC may also be integrally formed in the valve body by
overmolding. The pressure transducer may optionally be mounted on a
substrate or circuit board prior to overmolding. The substrate or
circuit board may contain electrical connector terminals which
engage the solenoid operator for the valve in plug-in engagement at
assembly. Optionally, the ASIC may include additional electronics
for controller functions in the valve for minimizing or eliminating
the amount of control functions and electronic circuitry required
for external or remote connection. The valve body has electrical
connector terminals which, on external engagement thereto, provide
in-circuit connection to both the transducer and the solenoid
operator for the valve; and, these terminals may be mounted on the
substrate or circuit board, if one is employed.
[0010] In its simplest form, the valve body has an integrally
formed pressure transducer for use in a closed loop control system
interfacing with a remotely disposed controller. However, the
electronic controller may be incorporated in the valve in an ASIC
which may be also formed integrally in the valve body such as by
overmolding.
[0011] The present invention has particular application in systems
requiring control of pneumatic or hydraulic actuators for effecting
a control function. The system has been found suitable for
applications on-board a motor vehicle where low voltage direct
current is an available power source for operating a solenoid
valve. The present invention provides an electrically operated
pressure control valve with a pressure transducer integrally formed
such as by overmolding to enable closed loop control mode of
operation from an electronic controller. An optional ASIC may also
be integrally formed in the valve body such as by overmolding to
enable incorporating the electronic controller in the valve to
provide self-contained closed loop control and thus provides a
"smart" valve.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a block diagram of one embodiment of the system of
the present invention;
[0013] FIG. 2 is an axonometric view of a valve employed in the
system of FIG. 1;
[0014] FIG. 3 is a section view taken through the longitudinal
center line of an embodiment of the valve of FIG. 2 employing a
circuit board;
[0015] FIG. 4 is a view similar to FIG. 2 with portions of the body
cut away to show the circuit board;
[0016] FIG. 5 is a partial section view taken longitudinally
off-center of the valve of FIG. 3 showing the connector terminals
on the circuit board.
[0017] FIG. 6 is a view similar to FIG. 1 of an embodiment with an
electronic controller formed integrally with the valve body;
[0018] FIG. 7 is a block diagram of the functions of the controller
of the system of FIG. 6;
[0019] FIG. 8 is a partial section view taken through the
longitudinal center line of the valve of FIG. 2 showing in detail a
technique for preparing the transducer on a circuit board for
overmolding;
[0020] FIG. 9 is a view similar to FIG. 8 of another technique for
preparing the transducer in a circuit board for overmolding;
[0021] FIG. 10 is a view similar to FIG. 8 of yet another technique
for preparing a transducer on a circuit board for overmolding;
and,
[0022] FIG. 11 is a view similar to FIG. 8 of an arrangement of the
valve with the transducer integrally formed by the two-shot
molding.
DETAILED DESCRIPTION OF THE INVENTION
[0023] Referring to FIG. 1, a system employing the present
invention for closed loop control is indicated generally at 10 as
having a source of fluid pressure 12 applied along a conduit 14 to
an electrically operated valve assembly indicated generally at 16
which includes an electric operator 18; and, the valve 16 includes
a pressure transducer 20 indicated in dashed outline and which is
integrally formed therein. In the present practice of the invention
it has been convenient to employ a solenoid for operator 18,
however, other types of electric operators may be employed such as
a bi-metal operator or a servo motor operating through a speed
reducer or a stepper motor. The control pressure output of the
valve is supplied along the conduit 22 to a fluid pressure actuator
24 which provides a mechanical output, indicated by dashed outline
26, to the desired load function 28. The embodiment of the valve
16, with operator 18, described and shown in the drawings has been
found suitable for use in a motor vehicle automatic transmission
application; however; the invention valve 16 may be used in any
fluid pressure control system of the type shown in FIG. 1.
[0024] In the embodiment illustrated, the valve 16 has an
electrical terminal 29 connected to provide an output signal from
transducer 20 along line 30 to an electronic controller 32. The
electronic controller 32 is operative to provide a pressure command
signal along line 34 to an electrical terminal 35 for power input
to the electrical operator 18. The electronic controller 32 may be
powered by an appropriate power supply 36 shown connected thereto
along line 38. In automotive applications valve operator 18 is of
the type capable of operating on the 12 volt DC on-board power. It
will be understood that controller 32 may optionally receive
program inputs as denoted by reference numeral 33 and the dashed
line connection in FIG. 1, such as from an on-board engine or
powertrain controller
[0025] The controller 32 may be programmed with a control algorithm
for generating the energization signal for the valve operator 18 to
give the required pressure to the actuator 24 for effecting the
desired function of load 28.
[0026] As will hereinafter be described in greater detail, the
transducer 20 may include an application specific integrated
circuit (ASIC) programmed with the valve response characteristics
of the particular type of valve and may thus minimize the
complexity of or eliminate the electronic circuitry required in
controller 32 to operate the valve in a particular system.
[0027] Referring to FIGS. 2 through 4, an embodiment of the valve
16 employed in the system of FIG. 1 is illustrated in greater
detail and includes a body 40 formed of non-metallic material. The
body may be formed by any suitable forming technique such as,
molding, injection molding, insert molding or casting. In the
present practice of the invention employing valve 16 it has been
found satisfactory to form the valve body of molded plastic
material which is chosen for compatibility with the service
environment and the fluids to be valved. In the present practice of
the invention, molded polyamide material partially filled with
glass particles has been found satisfactory for general usage with
water and air. However, for hydraulic oil applications, such as
automatic power transmissions for shift clutch control, it has been
found satisfactory to form the valve body of molded polyetheramide
material partially filled with particulate glass material. It has
also been found satisfactory to use polyetheramide material filled
with about ten to forty percent (10-40%) by volume fine glass
particles for hydraulic fluid applications. Another example of a
satisfactory material is polythalamide which may also be partially
filled with fine glass particles. These aforesaid materials have
been found particularly suitable for elevated temperature service
for temperatures up to about 140.degree. C. with hydraulic fluid.
It will be understood however that other materials suitable for
molding or casting may be used.
[0028] The valve body has a fluid pressure inlet 42 formed therein
which communicates with a valving chamber 44 having a moveable
valve member 46 disposed therein, which may have any desired
configuration suitable for the pressures encountered, such as a
spherical configuration which is moveable with respect to an
annular valve seat 48. The valve seat communicates with pressure
control outlet port 50 and also with a pressure sensing port 52
formed in the body, and for convenience extending to the opposite
side of the valve body from the outlet 50.
[0029] The moveable valve member 46 may be retained by any suitable
expedient such as by retainer 54 which for convenience has an
annular configuration and which is biased in a direction to close
the valve member 46 against seat 48 by a spring 56 retained and
sealed in the cavity 44 by a retaining plug 58.
[0030] The valve body 40 has a flux collector 60 attached to the
end thereof opposite the plug 58, which flux collector may have an
annular configuration as illustrated, with an elongated pole piece
portion 62 extending axially therefrom. The pole piece portion 62
has received thereover bobbin 64 which has disposed thereon a coil
66 of electrical conductor which is adapted for connection thereto
as will be described hereinafter.
[0031] The coil 66 may have an annular insulator 68 received
thereover. A second flux collector 70 which may have an annular
configuration is disposed on the end of the coil opposite the flux
collector 60; and, flux collector 70 also has a pole piece portion
72 extending interiorly of the bobbin.
[0032] An armature 74 is provided which may also have an annular
configuration, is disposed within the coil 66 and includes an
operating rod 76 portion disposed thereon and moveable therewith
and extending axially therefrom toward the valve member 46. The
operating rod may have a reduced diameter portion 78 formed
adjacent the end thereof and which is received through the valve
seat with the end thereof operable for contacting the valve member
46.
[0033] It will be understood that, in operation, energization of
the coil causes armature 74 and operating rod 76 to move
rightwardly with respect to FIG. 3 and displace the valve member 46
from the valve seat 48 to effect fluid flow from the chamber 44 to
the outlet 50.
[0034] Although a valve operator 18 comprising a solenoid has been
shown and described herein, it will be understood that other types
of valve operators may be employed such as electrically heated
bimetal operators or a servomotor operating through a speed reducer
or a stepper motor.
[0035] Referring to FIGS. 3 and 4, and as mentioned hereinabove
with respect to FIG. 1, the pressure transducer 20 includes a solid
state device or die 80, which may be of the piezoelectric or other
suitable variable impedance type, disposed over the sensing port 52
for sensing pressure therein. In the present practice of the
invention it has been found satisfactory to use a piezoelectric die
of the type commercially available from Sentir Semiconductor, Inc.,
Santa Clara, Calif. and bearing manufacturers APD301 Series 5000
Ohm Medium Pressure Sensor die. However, other types of solid state
devices may be employed which are designed to sense pressure in the
same range, and have similar electrical impedance properties and
are sufficiently robust to operate at temperatures of up to about
140.degree. C. while exposed to hydraulic fluids in elevated
temperature service, particularly motor vehicle automatic
transmission service.
[0036] In the simplest form of the invention, as shown in FIG. 1,
the die 80 may be overmolded directly in the material of the valve
body. In the embodiment of the valve 16 shown in the drawings, the
valve has the die 80 optionally, for convenience in molding,
mounted on a substrate, such as a circuit board 82, prior to
overmolding. The substrate or circuit board may be either of
flexible or rigid type and may be formed of suitable material, such
as ceramic or plastic material. As shown in the drawings, the
substrate or circuit board has terminal strips 84, 86 extending at
one end for connection to an electrical receptacle 85 provided on
the valve body. Alternatively, the substrate or circuit board may
have wires soldered or crimped to the solenoid coil conductor.
[0037] In the present practice of the invention it has been found
convenient to employ high temperature solder to attach the die 80
to a ceramic ring 81 or alternatively by other suitable techniques
such as that known as solder glassing; and, the die then wire
bonded at 83 to the substrate 82 as shown in greater detail in FIG.
8.
[0038] In the present practice of the invention the receptacle 85
may be provided on a bobbin flange, one of which is illustrated and
denoted by reference numeral 98. In the present practice of the
invention it has been found desirable to form the receptacle 85
integrally with receptacle 98 of bobbin 64. Upon plug-in connection
of the valve body terminal 86 into receptacle 85, electrical
contact may be made with the ends of the coil conductor by any well
known techniques such as by insulation displacement connection.
Alternatively, the connection may be made by soldering or crimping
to the coil conductor.
[0039] If desired, an optional ASIC 88 may be incorporated
integrally in the valve as shown in the drawing to simplify the
pressure command signal from the controller 32 needed to operate
the valve. The ASIC may be overmolded directly in the material of
valve body or may be optionally mounted on the substrate or circuit
board 82 prior to molding.
[0040] In the present practice of the invention, it has been found
satisfactory to insert-mold or overmold the transducer 20 by
placing the pressure transducer in a mold and overmolding the
material of the body 40 of the valve. However, it will be
understood that the transducer may be integrally formed in the body
by other techniques as, for example, casting body material over the
transducer. Although the die 80 is shown in the illustrated
embodiment as mounted on a substrate such as a circuit board, it
will be understood that the substrate or circuit board may be
omitted if desired and the die overmolded directly.
[0041] In the present practice of the invention, it has been found
advantageous to apply a coating or layer of viscous or pliable
material, such as a fluorosilicone or silicone gel over the die to
facilitate pressure distribution of the body material during
overmolding and to minimize the risk of damage to the connections
of bond wires 83 to die 80.
[0042] Referring to FIG. 9, the die 80 is shown as alternatively as
integrally formed, being covered with a protective cap 200, which
may be of any suitable non-conductive material such as ceramic or
other relatively rigid material which tends to absorb and dissipate
the pressure of the body material during overmolding. Referring to
FIG. 10, the die 80 is shown as alternatively integrally formed as
being surrounded by a guard ring 202 which may be of any suitable
material such as ceramic material, disposed on the upper side of
substrate or circuit board 82; and, the ring 202 may have a
suitable soft material 204 such as the aforesaid gel disposed
therein over die 80 to dissipate the pressure of the body material
during overmolding. Optionally, the gel may be covered by a thin
disc or cover plate (not shown).
[0043] In the event that the valve 16 will be exposed to unusually
severe installation or service conditions where a material is
chosen for the body 40 which has a relatively high hardness for
robustness and relatively high molding pressures are required, the
transducer may optionally be first overmolded with a plastic
material with greater compliance than the material chosen for the
body and subsequently insert molded with the desired body material,
such as by two-shot or insert molding. For example, the material of
the first shot or direct overmold of transducer 20 may have a
relatively high plasticity or softness; whereas, the desired body
material may have a relatively high stiffness or hardness, such as
by having a greater percentage of glass particulate fill than the
material employed for directly overmolding the transducer 20.
[0044] Referring to FIG. 11, an alternate embodiment of the valve
is indicated generally at 300 wherein the transducer indicated
generally at 320 is formed by mounting a die 380 on a substrate 382
and wire bonding the leads of the die to the circuit on the
substrate. The die and wire bonded leads are then covered with a
cap 302 and the transducer assembly 320 then inserted in a mold and
overmolded with material to form a subassembly indicated at 306 in
FIG. 11 which includes the receptacle 398 and terminal connector
pins such as 394. The subassembly 306 is then inserted in a mold
and overmolded with the material of the valve body 340 to form a
completed valve assembly. It will be understood that an aperture
308 is formed in the subassembly 306 to provide access of the
undersurface of the die 380 with the signal pressure port 352
formed in the valve body. The arrangement of FIG. 11 thus permits a
more compliant or softer material for the subassembly 306 to
facilitate molding about the transducer 320 and permits a harder
more robust material to be employed for the valve body 340.
[0045] Referring to FIGS. 3 and 4, in the illustrated embodiment,
the substrate or circuit board 82 may have the terminal strips, one
of which is illustrated and identified by reference numeral 86
mounted at one end through the circuit board 82, it will be
understood that the unshown terminal 84 may be similarly attached
to the substrate or circuit board 82. Alternatively, the terminals
may be connected with wires soldered to the substrate or circuit
board.
[0046] The opposite end of the circuit board has attached thereto a
plurality of connector pins 91, 92, 94, and 96, with one of the
pins 96 illustrated in FIG. 4; and, the pins 91, 92, 94, and 96
extend outwardly through the valve body and into a receptacle 98
which may be provided on the valve body for facilitating external
electrical connection thereto. In the present practice of the
invention, it has been found satisfactory to form the receptacle
integrally with the valve body, for example, by molding including
injection molding or casting.
[0047] A casing or shell 73 is received over the insulator 68 and
has one end thereof deformed, such as, by crimping over a body
flange 90 as shown in FIG. 2, with the opposite end deformed or
crimped radially inwardly at 75 over the end of the flux collector
70. The casing 73 may serve to complete a flux loop about the coil.
This arrangement thus retains the assembly of the pole pieces and
bobbin with coil onto the body. It will be understood that upon
making this assembly, the terminal strips 84, 86 engage the
receptacle 85 in plug-in engagement.
[0048] Referring to FIG. 6, another embodiment of the system of the
present invention is indicated generally at 100 and includes a
fluid pressure source 112, a pressure control valve 116 and an
electric valve operator 118 such as a solenoid. The valve 116 may
be electro-mechanically similar to that of the valve 16 described
hereinabove with reference to FIGS. 2-5 and is made in the same
manner such as by overmolding non-metallic body material over a
pressure transducer. For convenience of illustrations and
description the components of the valve 116 corresponding to those
of the valve 16 have the last two digits of the reference numerals
of FIG. 6 and FIG. 7, the same as those of the reference numerals
in FIGS. 1-5. The valve 116 receives at its inlet pressurized fluid
from source 112 along conduit 114. The valve 116 has integrally
formed therein a pressure transducer indicated generally at 120 and
which may be of the same type as described hereinabove for the
transducer 20. The valve 116 also includes integrally formed
therein an ASIC 188 which includes the functions of an electronic
controller as will be described hereinafter with greater
detail.
[0049] The outlet of valve 116 provides a fluid pressure signal
through conduit 122 to a fluid pressure actuator 124, the
mechanical output of which is applied, as indicated by the dashed
line in FIG. 6, to perform a load function indicated by reference
numeral 128. A power supply 136 provides the power source along
lines 130, 132 to the pressure transducer 120, the electrical
operator 118, and the controller comprising an ASIC 188 via
connection to terminals 129, 135 on the valve 116. If desired,
optional Program Inputs 133 may be supplied along dashed outline
139 to terminal 127 on the valve 116, which terminal it will be
understood is internally connected to the ASIC 188 as shown in
dashed line in FIG. 6.
[0050] Referring to FIG. 7, the operational functions incorporated
in the ASIC 188 are indicated as including regulator 137,
microprocessor 138, a memory 140, signal conditioning circuitry 142
for receiving the signal from pressure transducer 120 along line
144 and the valve operator drive circuitry 146 providing an output
along line 147 to the valve operator or solenoid 118. The power
supply 136 provides power to the ASIC as indicated along line
148.
[0051] A temperature compensation circuit 150 and a communications
circuit 152, such as, circuitry of the type for interfacing with a
CAN bus provides a communication signal along line 154.
Alternatively, communications circuit 152 may include other
protocols such as LIN, MOST, etc. and may also provide a voltage
signal such as a linear 0-5 Volt input signal.
[0052] The ASIC 188 may thus provide any one or any combination of
the following functions: (a) communications function, (b) a
microprocessor function for memory and algorithm calculations and
command signals, (c) a power driver and (d) a sensor signal
conditioning to amplify conditions and/or correct the sensor signal
including temperature correction, if required. The microprocessor
may be used to store local or low level algorithms such as PID type
control or similar control of the valve and may include diagnostic
routines. The valve operator drive electronics may include a power
transistor such as an FET and other pre-drive circuitry. The
communications bus is disposed to receive a signal and also report
solenoid valve output pressure. If desired, diagnostics may be
included such as for indicating a stuck valve by detecting no
change in output pressure in response to changes in the drive
signal. The signal conditioning temperature and compensation may
include amplifiers, filters and other similar circuitry to
condition the raw signal from the pressure transducer. The memory
may be used for storing constant gain values and desired fault
codes.
[0053] An advantage of the embodiment of the ASIC 188 shown in FIG.
7 is that the amount of calculation and control algorithm required
in the external system circuitry is minimized, thereby simplifying
the use of the valve in various systems, particularly a
transmission control module in an automotive automatic transmission
application. The arrangement of FIG. 7 may be a three connector
terminal device with power, ground and signal pins utilizing
internal connections to the solenoid, thereby minimizing the number
of external terminal connections required to the valve.
[0054] It will be understood that ASIC 188 may be programmed to
provide a predetermined pressure output signal in response to
varying temperature or inlet pressure or other environmental or
ambient conditions. Alternatively ASIC 188 may be circuit connected
to receive program inputs from an unshown source, but similar to
inputs 33 in FIG. 1.
[0055] The present invention thus provides a unique electrically
operated pressure control valve assembly with an integrally formed
pressure transducer sensing pressure at the valve outlet which,
when coupled with an electronic controller receiving the transducer
signal and in response thereto generating a valve control signal,
provides a system for closed loop control of the valve pressure
output. An ASIC may also be integrally formed with the body to
provide additional signal processing. In addition, the controller
may be disposed in the ASIC for providing a valve with self
contained electronic controller. Either or both the pressure
transducer and ASIC may be integrally formed in the material of the
body such as by overmolding, either directly or on a substrate or
circuit board. The electrically operated invention valve with
integral pressure transducer may thus be employed in a system for
providing closed loop pressure control of a fluid pressure signal
to a fluid pressure responsive actuator for performing a function,
such as operating shifting clutches in an automatic power
transmission for driving a vehicle.
[0056] Although the invention has hereinabove been described with
respect to the illustrated embodiments, it will be understood that
the invention is capable of modification and variation and is
limited only by the following claims.
* * * * *