Transmission with sump oil level responsive controls

A multiratio powershift transmission having automatic speed and torque demand responsive shift controls providing a normal shift program when the sump oil level is in the normal operating range. When the sump oil level is in an abnormal operating range, either lower or higher than the normal operating range, a sump oil level responsive control acts on the shift controls to provide an abnormal shift program preventing drive in the highest gear ratio and providing normal operation in the other gear ratio.

The invention relates to transmissions and particularly transmissions 
having an oil level responsive control for modifying transmission 
operation. 
The invention provides in a multiratio transmission having shift controls, 
a sump containing a fluid supply and a fluid supply system for supplying 
fluid from the sump to the transmission, a sump fluid level responsive 
control operative in response to sump fluid levels in a normal operating 
range of sump oil levels to permit normal transmission operation and 
operative in response to sump fluid levels beyond the normal operating 
range in an abnormal range of sump fluid levels to positively provide 
controlled abnormal transmission operation in a phase of transmission 
operation to indicate abnormal oil level condition and to continue 
drivable transmission operation in a phase of transmission operation. 
The invention provides in multiratio powershift transmissions having fluid 
operated power shift controls, a sump fluid level control operative in 
response to the normal sump fluid level range to provide normal shift 
operation, and in response to an abnormal sump fluid level range while the 
pressure source of the shift controls provides sufficient pressure for 
substantially normal drive operation, to provide abnormal drive operation 
in one phase and normal drive operation in another phase. 
In one arrangement, the abnormal sump fluid level is below the normal sump 
fluid level range. In another arrangement, the abnormal sump fluid level 
is both above and below, the normal sump fluid level range. The fluid 
level responsive control, in response to abnormal fluid level, preferably 
functions to control the shift controls to prevent an upshift to the 
highest ratio drive, and to provide a downshift from the highest ratio 
drive to prevent operation in the highest ratio drive. In a modification, 
only an upshift to the highest ratio drive is prevented. 
The invention is employed in a multiratio powershift transmissions having 
automatic speed and torque demand shift controls in which the fluid level 
responsive control provides, in the normal sump fluid level range, the 
normal automatic shift program and, in the abnormal sump fluid level 
range, an abnormal automatic shift program, having abnormal operation in 
one phase and normal operation in another phase, especially by preventing 
operation in the highest ratio drive, or by preventing an upshift to the 
highest ratio drive. 
The fluid level responsive control, in one arrangement, employs a fluidic 
jet device supplied with fluid pressure employed to establish the two 
highest ratio drives, the penultimate and highest ratio drive. This fluid 
supply is directed to the fluidic jet device sending portion which 
provides a free jet stream across an air gap to a receiving portion during 
abnormally low sump fluid level to provide a low fluid level signal in the 
receiving portion. During normal sump fluid level, sump fluid enters the 
gap to discontinue the low oil level signal. The sending portion has a jet 
nozzle providing a vertically upwardly directed jet stream with the jet 
outlet face at or slightly below the transition fluid level, between the 
normal fluid level range and the low fluid level range, to provide a 
sudden or high rate signal pressure change with small fluid level change 
at the transition level. 
The fluid level responsive control, in another arrangement, employs a 
fluidic jet device positioned above all sump fluid levels. When the sump 
fluid level is abnormally low, the fluid pump will suck air through the 
pump intake and pump aerated fluid to the transmission controls. Also, 
when the sump fluid level is abnormally high and contacts transmission 
gearing, the fluid will be frothed or aerated. The fluidic jet device 
provides a signal pressure, since nonaerated fluid provides a jet stream 
crossing the air gap, indicating normal sump fluid level. Since aerated 
fluid does not cross the air gap to provide a signal, the signal pressure 
is substantially reduced. The absence of the normal sump fluid level 
signal indicates abnormal sump fluid level and is used to provide abnormal 
transmission operation in one phase of operation. The fluidic jet device 
is more sensitive to aerated fluid and thus provides the abnormal oil 
level signal before aerated fluid causes abnormal operation in all phases 
of transmission operation.

The controls described below, for providing a signal changing the normal 
transmission control characteristics by preventing a shift from the 
penultimate ratio drive to the highest ratio drive in response to improper 
or abnormal fluid or oil level in the sump 22, are employed in a 
conventional multiratio transmission 10 having two or more ratio drives, 
powershift control and automatic speed and torque demand ratio control, as 
shown, for example, in U.S. Pat. No. 3,587,355 Schaefer, granted June 28, 
1971, and in the Schaefer and Fox U.S. Pat. No. 3,691,872, granted Sept. 
19, 1972, and incorporated herein by reference. 
FIG. 1 is a simplified diagrammatic view of such a transmission, having two 
ratio drives and illustrative of transmissions having more than two ratio 
drives. The transmission 10 has conventional powershift gearing 11 drive 
connecting the input shaft 12 to the output shaft 14 and selectively 
controlled by fluid operated low ratio drive device 16 to provide or 
establish a low or penultimate ratio drive, and fluid operated high ratio 
drive device 17 to provide or establish a high or highest ratio drive. A 
governor 18, driven by output shaft 14 is conventionally supplied with 
transmission control fluid and supplies governor pressure proportional to 
output speed to governor line 19. The transmission 10 has a housing 21 
with a sump 22, shown diagrammatically below in FIG. 1. The intake screen 
23 is located in the bottom of sump 22 and is connected by intake line 24 
to pump 26 which is drive connected to input shaft 12. When input shaft 12 
is driven by the engine, pump 26 supplies fluid to mainline 27. Regulator 
valve 28 regulates the fluid pressure in mainline 27, and the overage is 
connected by overage line 29 to the lubrication system. Mainline 27 or 
overage line 29 may be used to supply governor 18. 
The manual valve 31 selectively blocks mainline 27 in a neutral [N] 
position and connects mainline 27 to drive line 32 in forward drive [D] 
position. The shift valve 35 in valve body 36 has valve element 37, having 
lands a, b, and c, with the land a having a slightly smaller diameter than 
equal diameter lands b and c, located in stepped bore 38, and a control 
element 39, having progressively larger diameter lands d, e, and f, in a 
stepped bore 41. A spring 42, seated on fixed abutment 43, biases control 
element 39 and valve element 37 to the downshift position shown (FIG. 1). 
The abutment 43 has a ring 44 mounted in spring chamber 45, a portion of 
bore 41, and secured by pin 47, to valve body 36. The ring 44 may be 
constructed so it can be manually axially adjusted, as shown in the above 
Schaefer U.S. Pat. No. 3,587,355. A valve stop 48 is also secured by pin 
47 in valve stop position. There is a fluid passage 49 between valve stop 
48 and ring 44 for fluid communication between both ends of the spring 
chamber 45. 
With shift valve 35 in the downshift position shown, governor pressure in 
line 19 connected to governor chamber 51 provides an upshift bias force. 
The high apply line 52 is connected between valve element lands 37a and b 
to exhaust 54 to disengage high ratio drive device 17. The drive line 32 
is connected between lands 37b and c to low apply line 55 to engage low 
ratio drive device 16. Exhaust 56 is blocked by land 37c. The inverted 
modulator pressure line 57 is connected by its port 58 to control element 
bore 41 to act on the differential area of largest control element land 
39f, the area of land 39f less the smaller area of land 39e, to provide a 
torque demand bias force decreasing with increasing torque demand acting 
in opposition to the spring bias force, to provide a net downshift bias 
force in downshift position increasing with increasing torque demand. When 
the governor upshift bias force overcomes the net downshift bias force to 
upshift shift valve 35, drive line 32 is connected to high apply line 52 
to apply high ratio device 17 and provides the mainline hysteresis force, 
since apply pressure acts on the differential area between larger land 
37b, and smaller land 37a. Low apply line 55 is connected between lands 
37b and c to exhaust 56. Also, in upshift position, inverted modulator 
pressure in line 57 is connected by its port 58 to act on the larger 
differential area between control element largest land 39f and smallest 
land 39d, providing a larger torque demand bias force opposing the spring 
bias force to provide a lower net downshift bias force in upshift 
position, so downshifts occur at a lower output speed than upshifts. The 
hysteresis force or difference between upshift speed and downshift speed 
decreases with increasing throttle or torque demand during normal 
automatic torque demand and speed responsive shifting. During normal fluid 
level operation, the shift valve spring chamber 45 is connected to exhaust 
through the low fluid level signal line 82 which is exhausted by port 78 
at receiving portion 79 described below. 
The mainline 27 is connected to conventional modulator pressure regulator 
61, which is controlled by throttle pedal position, engine vacuum, or 
other torque demand signal, and provides an inverted torque demand 
modulated pressure in line 57, which decreases with increasing torque 
demand, and to a conventional detent valve 62 which is controlled by 
throttle pedal position or other torque demand signal, and provides at 
full-throttle or torque demand a regulated detent pressure in line 63, as 
shown in the above U.S. Pat. Nos. 3,587,355 and 3,691,872. The detent line 
63 is connected to ports 64, 65, of shift valve 35 to supply detent 
pressure to the space between the shift valve element 37 and control 
element 39 to disable control element 39 and provide shift valve operation 
for detent upshifts and downshifts in response to output speed at higher 
speed values than during the above-described normal automatic shifting in 
response to inverted modulator pressure and output speed. 
A fluidic jet device 67 is located in the sump 22 and has a plate 68 
secured by fasteners 69 to a vertical wall or support portion 71 of sump 
22. The fluidic jet device 67 has a jet sending portion 72 secured to or 
formed integrally with plate 68 and having an inlet port 73 connected to 
drive line 32. In this simplified two-drive ratio transmission 10 (FIG. 
1), drive line 32 functions as the supply for drive by the shift control 
system and is employed to supply fluid to the fluidic jet device 67 
because it supplies mainline fluid pressure in low and high ratio drives. 
Generically to include transmissions with more than two ratio drives, to 
supply fluid to the penultimate and highest ratio drives. In four-speed 
transmissions, as shown in the above Schaefer and Fox U.S. Pat. No. 
3,691,872, the equivalent is the 2-3 shift feed line 415 which feeds 
during operation in both 3rd and 4th ratio drives. The drive line or 
penultimate and highest ratio feed line 32 supplies fluid pressure to the 
vertically directed jet nozzle 74, ending at the top jet outlet surface 
75, which provides a vertically directed free fluid jet stream 76 from top 
surface 75, directed across the gap 77 between the jet nozzle 74 surface 
75 and the receiving port 78 in surface 80 of the receiving portion 79. 
The receiving port 78 has an entry area at face 80 about twice the area of 
nozzle 74 converging to an area about equal to the area of nozzle 74, as 
shown in FIG. 6 and described below, but the receiving port may have a 
straight bore receiving port having an area about twice the area of nozzle 
74. The receiving port 78 has a larger area than the nozzle as the free 
jet stream 76 spreads and to accommodate for alignment tolerance 
variations of the nozzle and receiving port. In the receiving portion 79, 
the receiving port 78 is connected to a delivery port 81 connected to low 
sump fluid signal line 82, which is connected to spring chamber 45 of 
shift valve 35. The sump 22 has a normal operating fluid or oil level 
range including the normal fluid level range from the full fluid level, 
FULL, down to the add oil level, ADD, and a lower operating oil level 
range. Below the normal operating oil level range, there is an abnormal 
operating fluid level range, an improper low fluid level, beginning at the 
transition or modified shift abnormally low fluid level, MOD. SHIFT LOW. 
When the fluid level is in the normal operating range, fluid in the gap 77 
dissipates by turbulence, the jet stream 76, so no low fluid signal 
pressure is developed at the receiving port 78, and the low fluid level 
signal line 82 exhausts spring chamber 45 for normal operation of the 
automatic shift valve 35. When the fluid level descends to the transition 
line, MOD. SHIFT LOW, at the top of the abnormally low fluid level range, 
which is at or slightly above the top outlet surface 75 of jet sending 
portion 72, and mainline fluid pressure is supplied by drive line 32 to 
supply nozzle 74, the nozzle provides jet stream 76. Since there is little 
or no fluid in the gap 77, the jet stream in air has laminar flow and 
impinges in receiving port 78 to develop the low sump fluid level signal 
in line 82 and spring chamber 45. The low sump fluid level signal is 
sufficient in high ratio drive to downshift and in low ratio drive to hold 
the shift valve 35 in downshifted position. The fluidic jet device 67 
provides an abrupt change in the signal pressure in line 82 with a small 
change in sump fluid level at the transition level or modified shift level 
between the normal and abnormal fluid level ranges. The control system 
fluid pressure source, pump 26 and regulator valve 28, supplies 
substantially proper operating pressure to mainline 27 and the control 
system for substantially proper positive transmission operation, to avoid 
improper operation, such as excessive slipping of ratio devices 16, 17, or 
loss or lubrication and cooling supply, in both the normal and abnormal 
shifting phases. The automatic low sump fluid level responsive change from 
normal shift operation to abnormal shift operation will change and reduce 
transmission performance and advise the operator of the abnormally low 
sump fluid level. 
The modified shift low fluid level pressure signal in line 82 is also used 
to actuate a pressure switch signal system 84, having a normally open 
pressure switch which closes in response to low fluid level signal 
pressure in line 82 and completes a sound or light signal circuit. 
FIG. 2 shows a modified structural arrangement of the components in the 
sump 86 of a transmission 87 having a housing 88 which is functionally 
like the above-described transmission 10 of FIG. 1. In FIG. 2, the 
controls have the same valves as FIG. 1, in valve body 89 mounted on 
support portion 91 of housing 88. The intake screen 92 is supported on 
support struts 93 connected to valve body 89 and also providing the intake 
line. The fluidic jet device 94, specifically described below and shown in 
more detail in FIG. 6, is secured to the lower surface of valve body 89. 
The FIG. 6 fluidic jet device 94 has one-piece construction with a 
vertical support portion 95, a horizontally projecting lower sending 
portion 96, and a horizontally projecting upper receiving portion 97. The 
drive line 98, which is supplied in the penultimate and highest ratio 
drives, is connected to a passage 99 extending from the top surface 101, 
down through the support portion 95 and then horizontally into the lower 
sending portion 96. A restricted nozzle 102 connects the passage 99 
through the sending portion 96 between passage 99 and the top outlet 
surface 103 of sending portion 96 to provide a fluid jet stream 105 
directed across gap 104 toward the conical receiving port 106 in the lower 
inlet surface 107 of receiving portion 97. The conical receiving port 106 
is connected by passage 108, having about the same diameter as nozzle 102, 
to passage 109 connected to low fluid level signal line 111. 
The modified portion of a further modification is shown in FIG. 3 with 
reference to FIG. 1 and the above description and employing; in FIG. 3, 
the same reference numerals, double-primed, for like parts. In the FIG. 3 
modified transmission and control, the shift valve 35" is prevented from 
upshifting, but is not downshifted by the abnormally low fluid level 
signal. Since this FIG. 3 modified transmission and control is the same as 
the above-described FIG. 1 transmission and control system, except for the 
connection of abnormally low sump fluid level signal line 82" to shift 
valve 35", only this modified portion is shown in FIG. 3. The shift valve 
35" has the same automatic shift components which function in the same way 
and the same connecting lines and exhausts, the governor line 19", 
exhausts 54" and 56", low and high ratio lines 52" and 55", as shown, and 
the equivalents of detent line 63 and ports 64, 65, and drive line 32 [not 
shown]. The spring 42" is similarly located in spring chamber 45" and 
seated on abutment 43". The control valve element 39" is modified by 
making land 39f" wider so it will, in the upshift position, block port 112 
of low fluid level signal line 82". The spring chamber 45" also has 
restricted exhaust 113 which has sufficient flow capacity to permit normal 
automatic shift operation during normal fluid level operation, when the 
exhaust provided by low fluid level signal port 112 and line 82", is 
blocked when shift valve 35" is in upshift position. 
Thus the abnormal low sump fluid level signal, when supplied by the fluidic 
jet device 67 to line 82" will, when the shift valve 35" is in downshift 
position, enter via signal port 112 to spring chamber 45" and prevent an 
upshift. Exhaust 113 is small, so sufficient low fluid signal pressure 
develops in spring chamber 45". After an automatic upshift when abnormal 
low sump fluid level signal is provided in line 82" to signal port 112, 
signal port 112 will be blocked by land 39f" so the shift valve 35" will 
not be downshifted. 
A further bilevel responsive control modification, shown in FIGS. 4 and 5, 
is employed in a transmission 10', like the transmission 10 of FIG. 1, so 
like reference numerals, primed, are used and reference to the above 
description of FIG. 1 is made for similar parts. The transmission 10' has 
multiratio gearing 11' connecting input shaft 12' to output shaft 14' in 
low ratio drive when low device 16' is supplied with fluid and in high 
ratio drive when high device 17' is supplied with fluid. The controls have 
output governor 18' supplying governor line 19' with governor pressure. 
The transmission housing 21' supports gearing 11' and has attached to its 
lower portion sump 22' which also completes the lower portion of the 
housing 21'. Intake screen 23' is located in the bottom of sump 22' and 
connected by intake line 24' to pump 26' which supplies mainline 27'. 
Mainline pressure is regulated by regulator valve 28' and overage line 29' 
connected to the lubrication system, LUBE. Manual valve 31' supplies drive 
line 32' supplies fluid in both the low and high ratio drives which, with 
general reference to multiratio transmissions, are the penultimate and 
highest ratio drives. 
The shift valve 35' is the same as FIG. 1 shift valve 35 and has the same 
passages and exhausts, indicated by primed numerals as shown 
diagrammatically in FIG. 5, and is located in valve body 36' positioned in 
the top of the sump 22' as shown in FIG. 4, and supported by a support 
[not shown] on housing 21'. A modulator pressure regulator valve, like 
valve 61 shown in FIG. 1, supplies inverted modulator pressure to 
modulator line 57'. A detent valve, like valve 62 shown in FIG. 1, 
supplies detent pressure to detent line 63' and ports 64' and 65'. In both 
FIGS. 1 and 5 the shaft valve 35 or 35' is the 1-2 shift valve in a 
two-speed transmission and may be the 3-4 shift valve in a four-speed 
transmission as shown in the above U.S. Pat. No. 3,691,872 Schaefer et al. 
The fluidic jet device 67', shown in FIG. 4, is positioned in the 
transmission housing 21 above the fluid level at all times, and is 
suitably fastened to and supported by the housing 21. The particular 
position and direction of the fluid jet stream 76' is not important. The 
fluidic jet device 67' similarly has a support portion 68', a jet sending 
portion 72', and receiving portion 79'. The drive line 32' is connected by 
inlet port 73' to feed jet nozzle 74' providing, beginning at surface 75', 
the fluid jet stream 76' directed toward receiving port 78' and connected 
to delivery port 81' in surface 80'. The jet nozzle 74' has a diameter 
about half as large as the diameter of the receiving port 78' to provide 
some tolerance for jet stream spread or diffusion and tolerance variation, 
such as alignment, and to provide a fluidic jet device providing a large 
decrease in the signal pressure when the fluid becomes aerated. 
The delivery port 81' is connected by a normal operating fluid level signal 
line 116 to a reversing valve 117 which, in the absence of the normal 
operating fluid level signal pressure, provides abnormal sump fluid level 
signal pressure in signal line 82', as in FIG. 1, to pressure switch 
signal system 84' and to shift valve 35' to prevent operation in the 
highest ratio drive. The reversing valve 117 has a valve element 118 
having equal diameter lands a and b in bore 119. In the absence of a 
normal sump fluid level signal in line 116 connected to chamber 121, the 
spring 122 in spring chamber 123 vented by exhaust 124 biases valve 
element 118 to the open position shown and connects drive line 32' to 
provide signal pressure in abnormal sump pressure signal line 82'. When 
the normal fluid level signal pressure is supplied in line 116 to chamber 
121 to act on land 118a, valve element 118 is moved to closed position, 
blocking drive line 32' and connecting abnormal sump fluid level signal 
line 82' to exhaust 125. 
The operation of the transmission gearing 11' and automatic shift control 
by shift valve 35' is the same as described above with reference to FIG. 
1. In the normal sump fluid level range between high level, HIGH OIL, and 
low level, LOW OIL, FIG. 4, normal nonaerated fluid is supplied by drive 
line 32' to fluidic jet device 67' which then provides a jet stream 76' 
across the air gap 77' to provide a normal sump fluid level signal in line 
116. This normal fluid level signal in line 116 acts on reversing valve 
117 which exhausts the abnormal sump fluid level signal line 82' to 
exhaust 125 to provide normal automatic shifting operation of shift valve 
35'. 
If the sump fluid level rises to an abnormal high level, HIGH OIL, the 
fluid contacts a lower rotating portion of the gearing 11' which aerates 
the fluid. If the sump fluid level decreases to an abnormal low level, LOW 
OIL, the screen 23' or other specially located inlet will permit air to 
enter intake line 24' and aerate the fluid. The fluidic jet device 67' 
does not provide a sufficiently homogenous and laminar flow jet stream 76' 
when supplied with aerated fluid to provide sufficient normal fluid level 
signal pressure in line 116 to actuate reversing valve 117 against the 
bias force of its spring 122. Then reversing valve 117 supplies abnormal 
sump fluid level signal pressure in line 82' to shift valve 35' to prevent 
upshifts to the highest ratio drive and to provide a downshift from the 
highest ratio drive to the penultimate ratio drive. When the sump fluid 
level is normal and the fluid in a nonaerated state, the fluidic jet 
device 67' provides a normal sump fluid level signal pressure in signal 
line 116 which signal pressure is reversed by reversing valve 117 to 
exhaust sump fluid level signal line 82' to permit normal automatic shift 
operation of shift valve 35'. The fluidic jet device 67', since the jet 
stream 76' is in air, is more sensitive to aerated air and so the jet 
device, in response to a low degree of aeration of the fluid, discontinues 
the normal fluid level signal. Since the fluid in the transmission control 
system is under pressure at this low degree of aeration, the transmission 
operating pressure is substantially proper to provide proper positive 
operation of the transmission. 
The modified fluidic jet device 94' shown in FIG. 7 is like the fluidic jet 
device 94 shown in FIG. 6 and described above, so like reference numerals, 
primed, are used with reference to the above description. The fluidic jet 
device 94' (FIG. 7), like the fluidic jet device 94 (FIG. 6) provides in 
the same way an abnormal low sump fluid level pressure signal to line 111 
when the sump fluid temperature is in the normal temperature range, and 
may be similarly used in the above-described transmission and control 
system shown in FIG. 1. When the sump fluid temperature is low, less than 
the normal fluid operating temperature range, the fluid level may be 
falsely or deceptively temporarily abnormally low, but on warming with 
normal transmission operation to a normal temperature, the level would 
increase to the normal sump fluid level range. In order to prevent a false 
low fluid signal at such low temperatures, a temperature responsive flow 
control means is provided to reduce or block flow of fluid to or in the 
jet nozzle, or to block the jet stream, so that abnormally low fluid level 
will not provide an abnormal low fluid level signal at such low 
temperatures below the operating temperature range. In FIG. 7, such a 
temperature responsive flow control means is provided by the long jet 
nozzle 102' having a length to diameter ratio of about 20:1, so that at 
such low temperatures, the jet stream 105' and abnormally low fluid level 
signal in line 111' will not be provided, even though the sump fluid level 
is abnormally low. Other temperature responsive flow control means, such 
as a temperature responsive bimetallic strip, a capsule, or other thermal 
motor controlled valve flow reducing member can be employed to close or 
restrict passage 99' or to interfere with jet stream 105' so the jet 
stream does not develop a low fluid level signal in low fluid level signal 
line 111'. 
It will be appreciated that other modifications of the invention may be 
made.