Abstract:
An engine coolant valve has a valve body with rotatable valve member thereon with a cylindrical configuration cross ported for rotary sealing against an arcuately shaped elastomeric face seal. A torque motor is attached to the valve body and has the motor rotor drivingly engaging a hub on the valve member.

Description:
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 water valves of the type intended for controlling flow of internal combustion engine coolant between the engine cooling passages and an exterior heat exchanger, for example, the heater core for a vehicle passenger compartment. 
     Heretofore, motor vehicle heater core water valves have typically either been manually actuated by a cable connected to a crank provided on the shaft of a butterfly plate type valve; or, the crank for the butterfly plate was connected by a link to a pressure operated diaphragm in a vacuum powered actuator. 
     Butterfly plate type water valves have proven to be generally reliable and low in manufacturing costs and thus have found widespread usage in automotive heater applications. However, butterfly plate type valves have the disadvantage of being quite non-linear in their flow control characteristics inasmuch as full flow of the valve occurs at about only one-quarter of the fully open position. This characteristic of butterfly type valves has resulted in difficulties in actuating the valve to obtain a predetermined amount of flow therethrough. Vacuum pressure actuators are limited in their size; and, thus the restricted diaphragm area limits the stroke resolution for pressure changes over the available range. Manual cable actuation has resulted in almost no useful modulation of the water flow. 
     Therefore it has been desired to provide an electrically operated heater core water valve to facilitate more accurate positioning of the valve member and therefore improved control over the flow of the coolant to the heater core. This is particularly desirable in a vehicle passenger compartment climate control system which is designed to provide automatic or thermostatically controlled temperature regulation in the passenger compartment. Heretofore electrically operated heater core water valves have employed a low voltage high RPM low torque motor driving a sector gear through a numerically high ratio gear reduction in order to provide the requisite torque needed to control the butterfly in the water valve and sufficiently fine resolution of the butterfly plate movement. Such servo motor operated speed reduced electric actuators have proven to be bulky and difficult to install on a water valve and in addition have resulted in relatively high manufacturing costs for the type of valve control desired. 
     Furthermore a motorized water valve employing a gear train does not permit automatic return of the valve to the open position in the event of electrical failure of the motor as is required in automotive passenger compartment heater applications. 
     Thus it has been desired to provide such a water valve for the passenger compartment heater core which will return to the fully open position in the event of failure of the servo motor. 
     In addition, it has long been desired to provide a simple, relatively low cost and reliable motorized water valve for controlling the flow to a vehicle passenger compartment heater core and to provide such a motorized valve which is compact and provides precision flow control. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a torque motor operated water valve suitable for controlling flow of engine coolant to a vehicle passenger compartment heater core. The valve assembly of the present invention has the torque motor mounted directly to the integrally formed inlet and outlet fittings with the motor rotor drivingly engaging a cross ported rotary valve spool or barrel type valve member. The valve member is assembled into the valve body with a curved sealing member which is disposed to seal between the face of the rotary valve member and one of the inlet and outlet port openings. The seal member is preferably formed of thermoplastic elastomer material. The cross ported barrel type valve of the present invention, having the valving port aligned centrally with the inlet and outlet port provides fine resolution of flow control, approaching that of a linear relationship between rotary movement of the valve member and flow. The invention valve provides a relatively low frictional torque resistance and thus enables the torque motor to readily and precisely position the valve member for the desired flow. The valve of the present invention is low in manufacturing cost and is particularly suitable for control by a microcomputer in an automatic temperature control system for the vehicle passenger compartment. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross-section of the assembled valve and motor of the present invention; and, 
     FIG. 2 is an exploded view of the assembly of FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 1 and 2, the electric servo operated valve assembly of the present invention is indicated generally at  10  and includes a valve body subassembly indicated generally at  12  and a motor subassembly indicated generally at  14 . The valve body subassembly  12  includes a housing  16  having formed therein a generally cylindrical valving chamber  18  and an inlet port fitting  20  extending laterally therefrom and an oppositely directed outlet fitting  22  extending from the housing  16  generally in alignment with the fitting  20 . Fitting  20  has an inlet passage  24  formed therein which is ported to the valving chamber  18  at  26 ; and, outlet fitting  22  has formed therein an outlet passage  28  which is ported at  30  to the valving chamber  18 . 
     The inlet fitting  22  has a stanchion or raised boss  32  formed thereon; and, similarly the inlet fitting  20  has a stanchion or raised boss  34  formed thereon which extends in generally spaced parallel relationship with the stanchion  32 . 
     The valving chamber  18  has an arcuate slot or groove  36  formed therein and centered about the inlet port  26 . In the presently preferred practice of the invention, the radially extending sides of the groove  36  are slightly undercut for axial sliding engagement therewith. Undercut region of the sides of the groove  36  is denoted by reference numeral  37  in FIG.  2 . 
     A resilient face sealing member  38  has a generally convex or concave partial cylindrical configuration when viewed from the edge thereof as illustrated in FIG.  2  and has a generally rectangular plan form configuration with the axially extending oppositely disposed sides thereof notched as indicated by reference numeral  40 ,  41  for sliding engagement with the undercut side of the groove  36 . 
     The face seal member  38  has a centrally disposed aperture  42  formed therethrough which is sized to conform with the size of the inlet port  26 . The face seal member  38  is received in the valving chamber in axial sliding assembly with the notches  40 ,  41  engaging the undercut sides  37  of the groove  36 . It will be understood that when the face seal  38  is assembled in the groove  36  of valving chamber  18 , that the radial thickness of portions of the face seal is such that such portions face seal on face  44  are configured to extend radially inwardly of the cylindrical wall of the chamber  18  by a suitable amount for ensuring a positive seal thereagainst. 
     A rotary valve member  46  having a generally cylindrical or barrel-like configuration has an inlet aperture  48  formed therein on the cylindrical face thereof and which communicates with a similar aperture  50  formed on the opposite side of the barrel  46  as shown in FIG.  1  and in dashed outline in FIG.  2 . Rotary valve member or barrel  46  has an upwardly extending hub  52 . 
     Hub  52  has extending upwardly therefrom a driving surface in the form of a stub shaft having a square transverse section as denoted by reference numeral  54  and which engages corresponding surfaces  58  provided on rotor  56  of motor  14 . A seal ring  60  is disposed about the hub  52  and provides a seal between the hub and cover plate  62 . 
     The motor  14  is attached to a body  16  by brackets  64 ,  66  disposed on opposite sides of the motor and each of which has an aperture therein through which is received a fastener such as screws  68 ,  70  which threadedly engage respectively bosses  32 ,  34  to retain the motor on the body. A guide pin  72  serves to pilot the motor rotor engagement with driving surface  54 . 
     A torsion spring  74  is disposed about the hub  52  and has one end  76  anchored in the motor rotor with an opposite reaction end  78  thereof anchored in bracket  64 ; and, spring  74  serves to return the motor rotor and hub  52  to a position rotating the barrel  46  to the open position permit flow through the valve in the event of de-energization of the motor  14 . 
     In operation, the torque motor is operable upon selective energization to rotate the barrel from a position allowing full flow through the inlet and outlet of the valve body to various position restricting the flow until the flow is completely blocked by rotation of the barrel  48 . 
     The present invention thus provides a relatively low cost, simple and reliable construction for a motorized coolant valve for controlling flow between an inlet and an outlet and is particularly suitable for use with engine coolant supplied to a vehicle passenger compartment heater core and provides the desired resolution of flow with rotation of the valve barrel by a torque motor requiring a minimum of current to rotate the valve member. 
     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.