Torque converter clutch with a temperature regulator valve

A torque converter clutch is provided with a temperature responsive valve which controls fluid flow from the apply chamber to the release chamber which is connected to exhaust. The increased fluid flow provides additional cooling for a viscous clutch which is included in the torque converter clutch.

This invention relates to torque converter clutches and more particularly 
to such clutches having a temperature regulator valve for controlling 
fluid temperature in the clutch apply chamber. 
It is an object of this invention to provide an improved torque converter 
clutch having a valve mechanism responsive to the temperature in the 
clutch apply chamber to control the fluid flow from the chamber. 
It is another object of this invention to provide an improved torque 
converter clutch having a temperature responsive valve mechanism for 
increasing fluid flow across the clutch apply pressure plate as the 
temperature of the fluid in the apply chamber increases.

These and other objects and advantages of the present invention will be 
more apparent from the following description and drawing in which is shown 
a torque converter, generally designated 10, including a bladed impeller 
member 12, a bladed turbine member 14 and a bladed stator member 16. The 
impeller 12 is secured to an annular dish-shaped input shell 18 which is 
adapted to drivingly connect to an internal combustion engine, not shown. 
The turbine 14 has a hub member 20 including a splined diameter 22 which 
is drivingly connected to a torque converter output shaft 24. The torque 
converter output shaft 24 is rotatably supported in a bushing 26 secured 
in the input shell 18. The stator 16 includes a one-way device 28 having a 
hub portion 30 which is adapted to be connected to a stator shaft, not 
shown, in a conventional manner. 
The input shell 18 and turbine 14 cooperate to form a clutch chamber 32 in 
which is disposed a torque converter clutch, generally designated 34. The 
torque converter clutch separates the clutch chamber 32 into an apply 
chamber 36 formed between the clutch 34 and the turbine 14 and a release 
chamber 38 formed between the input shell 18 and the clutch 34. The 
release chamber 38 is in fluid communication with a fluid passage 40 
formed in the transmission output shaft 24. The passage 40 is connected to 
high pressure fluid in a well-known manner when it is desirable to 
disengage or release the clutch 34. 
The clutch 34 incorporates two clutch structures disposed in serial drive 
relationship. These clutch structures are a friction clutch 42 and a 
viscous shear clutch, generally designated 44. The friction clutch 42 has 
a friction facing 46 and a pressure plate 48. The pressure plate 48 also 
forms a portion of the viscous clutch 44. The pressure plate 48 responds 
to fluid pressure in the apply chamber 36 to cause frictional engagement 
between the input shell 18 and the friction facing 46. 
The viscous clutch 44 has a housing member 50 secured to the pressure plate 
48 and cooperating therewith to form a fluid cavity 52 in which is 
disposed a clutch output member 54 having a hub 56 which is splined to the 
hub 20. The pressure plate 48 has a plurality of axially extending annular 
projections 58 which are interleaved with a corresponding plurality of 
axially extending annular projections 60 formed on the clutch output 
member 54. 
As is well-known, the annular projections 58 and 60 transmit torque when 
they are in the presence of a highly viscous fluid, such as silicone oil. 
It is also known that such clutch structures generate heat due to the 
slipping phenomenon which must be removed to prevent damage. The heat 
generated in the viscous clutch is removed by the hydraulic fluid in the 
torque converter which circulates in the apply chamber 36 and the release 
chamber 38 adjacent the viscous clutch 44. 
The pressure plate 48 has secured thereto a thermostatic or bimetal valve 
62 which covers aperture or opening 64 extending between the apply chamber 
36 and the release chamber 38. The bimetal valve 62 is urged to a position 
to close the aperture 64 by fluid pressure in apply chamber 36, until a 
predetermined temperature, for example 180.degree. F. (83.degree. C.), is 
present in the fluid in the apply chamber 36. If this temperature is 
exceeded, the bimetal valve 62 will begin to open to permit fluid flow 
from the apply chamber 36 to the release chamber 38. A portion of the 
fluid leaving release chamber 38 passes through a cooler, not shown, prior 
to returning to the transmission sump, not shown. The fluid entering the 
apply chamber 36 is cooler than the fluid within the chamber. The heat 
generated in the viscous clutch 44 is conveyed to the fluid in apply 
chamber 36 and release chamber 38. The cooler incoming fluid increases the 
heat rejection from the viscous clutch 44. 
If the temperature of the fluid in apply chamber 36 increases significantly 
above the threshold temperature (i.e. 180.degree. F.), the flow through 
bimetal valve 62 will be sufficient to reduce the apply force of friction 
clutch 42. Thus, the torque capacity of clutch 42 is reduced to 
accommodate the reduction in the torque transmitted by viscous clutch 44 
due to the high temperature. Therefore, the temperature of the viscous 
fluid will decrease due to both the decrease in energy transmitted and the 
increased fluid flow through bimetal valve 62. 
The silicone fluid within the viscous clutch 44 is sealed in the clutch 
cavity 52 by an outer annular seal 66 and a pair of lip-type seals 68 and 
70 disposed adjacent the inner confines of the clutch cavity 52. Since 
this is a closed system, the only heat rejection possible is via the 
hydraulic fluid circulated through the torque converter 10. Thus, the 
fluid flow through the bimetal valve 62 is a desirable feature, as pointed 
out above, for increased heat rejection capacity which may be necessary. 
This bimetal valve 62 can be used in conjunction with a pressure 
differential valve such as that shown in U.S. patent application Ser. No. 
318,327 filed Nov. 5, 1981 and assigned to the assignee of this 
application.