Butterfly valve assembly

A valve of the type for controlling engine coolant flow to a heater core having a resilient butterfly valve formed of thermoplastic elastomeric material. The outer periphery is sufficiently resilient to absorb actuator overtravel in the seated condition. The butterfly has formed integrally therewith a central hub with torque-transmitting surfaces molded therein and a pair of oppositely disposed stiffeners extend outwardly from the hub in the central region of the butterfly. Assembly is simplified by placing the butterfly in the body and inserting a winged actuator shaft through journal holes in the body into the butterfly hub such that the wings on the shaft engage the torque-transmitting surfaces in the hub.

BACKGROUND OF THE INVENTION 
The present invention relates to valves of the type employing a pivoted 
butterfly type movable valve member. Valves of this type are typically 
employed in automotive applications for controlling flow of engine coolant 
to and from the passenger compartment heat exchanger or heater core. In 
such automotive heater core valve applications, it is known to provide a 
metal butterfly plate spot welded to a pivot shaft rotatably mounted 
through the walls of the valve housing for connection to an external 
actuator. Metal plate butterfly valves employed for automotive heater core 
applications typically are fabricated by inserting the valve plate in a 
mold and molding an elastomeric bead-rim thereabout for facilitating 
sealing of the periphery of the metal plate about the wall of the flow 
passage in the valve housing which is typically formed of die-cast metal 
or molded thermoplastic material. This method of construction by molding 
an elastomeric rim on a metal plate and then spot welding the plate to the 
actuator shaft in the valve housing has proven to be quite costly in the 
high volume mass production required for automotive heater valve 
applications. 
Furthermore, the aforesaid butterfly valve construction having a metal 
butterfly spot welded to the actuator shaft has been prone to breakage of 
the spot welds in service where the actuator shaft experiences overtravel, 
after the butterfly valve has closed against the wall of the flow passage 
in the valve, particularly in servomotor powered valve applications. Thus 
it has been desired to find a way or means of constructing a butterfly 
valve which is capable of being mass produced in high volume, such as for 
automotive heater applications, at a low manufacturing cost, and which 
provides reliable service and will readily absorb some degree of actuator 
overtravel in service without breakage. 
SUMMARY OF THE INVENTION 
The present invention provides a butterfly valve of the type suitable for 
controlling engine coolant flow in automotive heater core applications and 
which is relatively low in manufacturing cost and capable of absorbing 
some actuator overtravel after closing without breakage. 
The valve of the present invention has its porting arranged for controlling 
flow as a diverter or by pass valve, and has a molded plastic valve body 
with a butterfly valve member formed of molded elastomeric material. The 
valve member has formed integrally therewith a hub portion with torque 
transmitting surfaces therein and stiffening ribs extending outwardly from 
the hub and a relatively thin resiliently deformable outer periphery which 
is capable of absorbing some overtravel rotation of the hub after seating 
of the outer periphery. The metal actuator shaft is axially slidably 
assembled in the hub and has surfaces such as "wings" formed thereon which 
positively engage the torque transmitting surfaces in the hub. In an 
alternate embodiment, the central region of the butterfly has a metal 
reinforcing plate insert-molded therein. The butterfly is preferably 
formed of thermoplastic elastomeric material having a hardness not greater 
than 50 on the shore "D" scale.

DETAILED DESCRIPTION 
Referring to FIG. 1, the valve assembly of the present invention is 
indicated generally at 10 and has a valve housing or body comprised of an 
inlet section 12 and an outlet section 14 joined along a parting line 16 
by any suitable expedient such as clamping or alternatively weldment. 
Housing sections 12, 14 are preferably each formed of molded plastic 
material with a rim or flange formed about the parting line as denoted 
respectively by reference numerals 18,20. In the presently preferred 
practice, the body sections 12, 14 are formed of a polyamide material 
having a hardness of 115 on the Rockwell "R" scale, having preferably a 
40% by volume fill of fine glass particles. Flange 20 is formed with a 
circumferential groove on the parting line side thereof in which is 
received a resilient sealing ring 22. Flanges 18,20 are held together at 
the parting line by a peripheral clamping band 24, compressing sealing 
ring 22 therebetween. 
Housing section 12 defines an internal valving chamber 26 having oppositely 
disposed aligned inlet nipples or bosses 28,30 formed thereon integrally 
therewith adjacent parting line 16 and defining, respectively, inlet 
passages 32,34, each of which communicates with valving chamber 26. 
Housing section 12 has a third nipple 36 formed integrally thereon and 
disposed distal the parting line 26, preferably in spaced generally 
parallel arrangement with nipple 30. Nipple 36 has an outlet passage 38 
formed therein which also communicates with valving chamber 26. Housing 
section 14 has a fourth nipple 40 provided thereon and preferably arranged 
in spaced parallel arrangement with nipple 30. Nipple 40 has an outlet 
passage 42 formed therein which communicates with an interior flow chamber 
44 which is open across parting line 16 to chamber 26. 
Referring to FIGS. 1 and 2, a movable valving subassembly indicated 
generally at 46 is mounted in chamber 26 for pivotal movement between the 
position shown in solid outline and the position shown in dashed outline 
in FIG. 1. 
Referring to FIG. 2, valving sub-assembly 46 includes a butterfly member 48 
formed of molded elastomeric material and preferably thermoplastic 
elastomer having a hardness not greater than 50 on the shore "D" scale. 
One material that has been found satisfactory is available from Monsanto 
Corporation, and bears manufacturer's designation 103-40. However, it will 
be understood that other suitable thermoplastic elastomeric materials 
exhibiting the same properties may be used. Butterfly 48 has a hub portion 
indicated by reference numeral 50 which has torque-transmitting surfaces 
formed therein such as the opposed slots as denoted by reference numerals 
52,53. Butterfly 48 also has formed integrally therewith stiffening ribs 
54,56 extending in opposite directions outwardly from hub portion 50. The 
peripheral region of butterfly 48, remote from hub 50, and ribs 54,56 is 
substantially reduced in thickness from the hub and ribs, and provides 
resiliency to the periphery of the butterfly 48 for absorbing actuator 
shaft overtravel in the seated condition. 
An actuator shaft 58, preferably formed of metal has torque-transmitters 
preferably oppositely disposed outwardly-extending tabs or wings 60,62 
formed thereon. Shaft 58 is slidably received in hub 50 with the wings 
60,62 engaging slots 52,53 for transmitting torque applied to shaft 58 to 
butterfly 48. 
At assembly, the butterfly 48 is assembled into chamber 26 of housing 
section 12 and shaft 58 inserted through oppositely disposed aligned holes 
(not shown) in member 12 for engaging hub 50 of the butterfly 48 with the 
shaft journalled in the unshown holes. 
In an alternative embodiment of valving subassembly 46, an optional metal 
reinforcing plate 64 is molded in the central portion of the butterfly 48 
in the position shown in dashed outline in FIG. 2 for providing stiffening 
instead of stiffeners 54,56. 
In operation, in an automotive heater core application, nipple 28 is 
connected to a source of engine coolant, such as a coolant pump (not 
shown), and nipple 36 is connected to the inlet of the heater core shown 
in phantom outline and denoted by reference numeral 70; and, nipple 34 is 
connected to the heater core outlet. Nipple 42 is connected to the return 
or coolant pump inlet (not shown). When the valving subassembly 46 is in 
the position shown in solid outline in FIG. 2 with the periphery of 
butterfly 48 sealed against the interior wall 66 of chamber 26, flow from 
inlet 32 goes through outlet 38 typically to the heater core 70 and is 
typically returned from the heater 70 through passage 34 into chamber 44 
and flows through passage 42 typically to the return or pump inlet. 
When the valving sub-assembly 46 is rotated to the position shown in dashed 
outline in FIG. 1, passages 38,34 are isolated from inlet 32 and flow 
therefrom is diverted directly to return passage 42. In a typical 
automotive heater application, the position of the valve subassembly 46 
shown in dashed outline in FIG. 1 would represent the heater "OFF" 
condition. 
The present invention thus provides a diverter valve, particularly suitable 
for controlling engine coolant flow in automotive heater applications, 
which employs a thermoplastic elastomer butterfly with a resiliently 
deformable periphery which is capable of absorbing actuator shaft 
overtravel in the closed or sealed position. The butterfly is formed with 
an integrally molded hub having torque-transmitting surfaces therein and 
oppositely directed stiffening ribs extending outwardly from the hub for 
stiffening the central region of the butterfly. Assembly is simplified by 
placing the butterfly in the valve body and axially sliding the winged 
actuator shaft through journals in the body into the hub such that the 
wings engaged the torque-transmitting surfaces in the butterfly hub. 
Although the invention has 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.