Servo motor operated rotary bypass valve

A motorized bypass valve having a valve body with cylindrical valving chambers with a single inlet and a first and second outlet ported to the chamber, such with convexo-concave face seals disposed over the ports. A rotary valving member having a partial cylindrical valving surface is disposed in the valving chamber and valving surface contacting the face seals. A motor housing is then spin welded onto the valve body to seal the valving chamber with the half shaft of the valving member extending into the motor housing and sealed by an O-ring. The motor and gear train are then assembled into the housing for driving the half shaft. The motor housing is closed by a cover welded thereover.

CROSS-REFERENCE TO RELATED APPLICATIONS
 Not Applicable
 STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
 Not Applicable
 MICROFICHE APPENDIX
 Not Applicable
 BACKGROUND OF THE INVENTION
 The present invention relates to servo motor operated valves and
 particularly electrically operated valves of the type having a single
 inlet and plural outlets wherein a rotary valve member is progressively
 moved from an initial position blocking flow to one of the outlets and
 diverting flow to the remaining outlets progressively through positions
 permitting increasing flow through the one outlet and decreasing flow
 through the remaining outlets until full flow is directed through the one
 outlet.
 Valves of this type are typically employed in a fluid flow circuit wherein
 it is desired in certain modes of operation to divert or bypass a portion
 of the flow for control purposes to a working fluid circuit and to divert
 the remainder of the flow away from the working load circuit such as to a
 sump or pump return.
 The aforesaid type of bypass or diverted flow is desired in controlling
 flow of hot water or engine coolant to a heat exchanger or heater core for
 a motor vehicle passenger compartment climate control system, typically
 for heating the passenger compartment. In such automotive passenger
 compartment heaters, it is desired to control flow of the hot water to the
 heater core by diverting or bypassing a portion of the flow to the heater
 and directing the remaining portion to return to the engine coolant
 circuit or engine water pump inlet. Such an arrangement provides for
 accurate control of the flow of hot water to the heater core and thus
 gives the desired resolution of temperature control of the passenger
 compartment.
 Heretofore bypass water valves for motor vehicle passenger compartment
 heater cores have typically been of the butterfly or rotary vane type
 which, have been employed because of their simplicity and low
 manufacturing cost, but which have the disadvantage or drawback of
 providing full flow between the closed position and about one-fourth of
 the full open position of the butterfly. This high gain change of flow
 with respect to rotary valve movement has caused the butterfly member in
 the valve to require a very fine control of its rotary position.
 Where it has been desired to provide an electronically controlled automatic
 temperature control system for the vehicle passenger compartment,
 utilization of a motorized actuator for the bypass water valve has
 required extremely fine resolution of the motor actuator output and thus
 has proven to be difficult and costly with respect to the overall cost of
 the valve and heater system.
 Thus, it has been desired to provide a bypass water valve for motor vehicle
 passenger compartment heater systems which provides accurate control of
 the flow and fine resolution of the flow with respect to movement of the
 valving member. It has further been desired to provide a linear
 relationship between the rotary movement of the valving member and the
 change in the diverted flow through the valve to the working load circuit.
 Known servo motor actuated rotary water valves have required separate
 fasteners to attach the motor drive unit to the valve body, utilizing a
 sealing gasket and has the disadvantage of being a source of leakage and
 being costly in high volume mass production. It has thus been desired to
 provide such a servo motor actuated rotary valve for heater bypass flow
 control which provides linearity of control, simplicity of design and ease
 of assembly, robustness as to fluid seal integrity and reduced
 manufacturing cost.
 BRIEF SUMMARY OF THE INVENTION
 The present invention provides a servo motor actuated bypass type rotary
 valve which has a simplified construction eliminating fasteners for the
 assembly of servo motor unit and valve body, has linearity of flow
 response and which is low in manufacturing cost and reliably sealed and
 thus robust in service. The servo motor actuated valve of the present
 invention employs a cylindrical valving chamber with a partially valving
 member having a partially cylindrically-shaped valving surface rotated
 over face seals provided at each of the valve outlets. The servo motor is
 operative to rotate the valving member from a position blocking one outlet
 to a position at least partially blocking the outlet and progressively to
 a position fully opening the one outlet and blocking the remaining outlet.
 The valve body has the valving member and face seals for each of the
 outlet ports assembled into the valving chamber as a subassembly and an
 annular seal ring is provided between the valving member and the housing.
 The servo motor housing is then attached to the body subassembly by spin
 welding the housing onto the valve body about the valving member.
 Subsequently the motor and gear train are assembled into the housing which
 is closed over the motor and gear drive by a cover welded to the housing.
 The valve of the present invention thus provides a linearly responding
 diverter valve having a simplified assembly, low cost with seal integrity
 for the valve body and valving chamber which employs spin welding for
 attachment of the servo motor to the valve body.

DETAILED DESCRIPTION OF THE INVENTION
 Referring to FIGS. 1 through 5, the valve assembly of the present invention
 is indicated generally at 10 and includes a valve body 12 having a
 cylindrical valving chamber 14 formed therein with an inlet fitting 16
 having an inlet passage 18 formed therein which communicates with the
 valving chamber 14. Body 12 has a primary outlet fitting 20 having therein
 an outlet passage 22 which communicates with valving chamber 14; and,
 fitting 20 is adapted for connection to a working fluid load circuit such
 as the inlet of a vehicle heater core 24. Inlet fitting 16 is adapted for
 connection to a source of fluid as, for example, a tap in the water jacket
 of an engine 26.
 Valve body 12 has a bypass or secondary outlet passage 28 formed therein
 which communicates through a fitting 30 with secondary or bypass channel
 32 formed in connector fitting 34 and also with channel 36 formed in
 connector 38. Connector 34 is adapted for connection to the return from
 the working fluid circuit such as the outlet of heater core 24; and,
 fitting 38 is adapted for providing return flow to the source, as for
 example, the return flow inlet to the supply, such as the inlet of the
 engine coolant water pump.
 In the presently preferred practice, the body 12 including fittings 16, 20,
 34, 38 and fitting 30 is formed integrally as a single piece with valving
 chamber 14 formed therein. Passage 28 is closed by a closure or a cap 40
 secured thereover by any suitable expedient, as for example, adhesive
 sealant or weldment. In the present practice of the invention, the body,
 cap and fittings are made of suitable plastic material, as for example,
 polyamide material filled about one-third by volume with glass particles.
 A rotary valving member 42 having a partial cylindrical valving surface 44
 formed thereon and a half shaft 46 extending therefrom with driving
 surfaces 48 provided thereon. An annular resilient seal ring 66 is
 received over half shaft 46 in sealing engagement therewith. Member 42 is
 received in valving chamber 14 for rotation therein with half shaft 46
 extending outwardly from chamber 14.
 A first and second convexo-concave or partially cylindrical face seal
 members 50, 52, formed of resilient seal material, as for example,
 elastomeric material have spaced parallel sides or margins which are each
 received in a pair of grooves provided in the valving chamber wall and
 denoted by reference numerals 54, 56. Each of the seal members 50, 52 has
 a flow aperture denoted respectively 58, 60 formed therethrough and which
 has an annular lip or rib formed thereabout on the interior or concave
 face thereof as denoted respectively by reference numerals 62, 64.
 The assemblage of the body 12, seals 50, 52, valving member 42 and seal
 ring 66 comprise a subassembly indicated generally at 68.
 A servo motor drive unit indicated generally at 70 includes a housing shell
 72 and cover 74 with a motor 76 mounted in the shell 72.
 The motor unit 70 is a built up assembly in housing shell 72. Housing shell
 72 has an aperture 78 formed in the bottom thereof which is received over
 the half shaft 46 in clearance arrangement therewith; and, the housing
 shell 72 is secured over the valving chamber 14 and to the subassembly 68
 by spin welding so as to seal chamber 14 and secure the housing 72 to the
 body 12. It will be understood that during the spin welding operation, the
 housing 72, seal ring 66 rotates with respect to valving member 42; and,
 seal ring 66 seals between half shaft 46 and aperture 78.
 After the spin welding of housing shell 72 to subassembly 68, the motor 76
 is placed in housing shell 72 and secured therein between mounts 77, 79.
 The motor 76 has an output worm 78 on the shaft thereof which engages a
 first stage driven gear 80 mounted on axle pin 82 which is secured in the
 housing shell 72. Gear 80 has provided thereon a first stage pinion 84
 which engages a second stage gear wheel 86 mounted on axle pin 88 secured
 in the housing 72. Gear wheel 86 has thereon a second stage pinion 90
 which engages an output gear 92 which is received over half shaft 46 and
 has the hub 94 thereof drivingly engaging surfaces 48. Output gear hub 94
 is journalled in an aperture 96 formed in a deck plate 98 which is secured
 to housing shell 72 over locating lugs 100 and retained thereon by any
 suitable expedient, as for example, by heat staking of the lugs through
 apertures 102 formed in the deck plate 98. If desired, a resistor (not
 shown) may be provided on the undersurface of deck plate 98 and wiped with
 an electrical wiper contact 104 provided on the output gear 92 thereby
 forming a potentiometer for providing a position feedback signal for
 output gear 92 and shaft 46.
 Upon completion of the assembly of the motor 76 and associated gears in the
 housing 72, cover 74 is received thereover and engages pegs 106 provided
 on the housing 72 and is secured thereto by any convenient technique, as
 for example, by sonic weldment.
 The present invention thus provides a low cost and reliably sealed bypass
 type rotary valve which has a partial cylindrical valving surface slidably
 contacting face seals disposed over radial valve ports in a cylindrical
 valving chamber and which provides substantially linear control of the
 flow with respect to the rotary position of the valving member. A servo
 motor housing shell is spin welded to the valve body to close the valving
 chamber after assembly of the valving member and seals in the valve body
 as a subassembly. The servo motor and gear train are then assembled in the
 housing shell. The present invention thus provides a simple to construct,
 relatively low cost, reliably sealed bypass valve with substantially
 linear response to an electrical input signal for the servo motor and
 which is particularly suitable for use as a heater core water bypass valve
 in a motor vehicle passenger compartment climate control system.
 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.