Automatic transmission

An automatic transmission includes a casing housing a transmission mechanism and having a wall with a through-hole. A first plurality of electronic components is mounted exterior to the casing and a second plurality of electronic components is mounted on the interior of the casing. A sealed wire terminal is mounted in and closes the through-hole 21. An electronic control unit is mounted in the sealed wire terminal 22 and cables electrically connect the electronic control unit to the first and second pluralities of electronic components. The sealed wire terminal includes a seal member supporting the cables and sealing the through-hole. Thus, the automatic transmission and the electronic control unit can be combined before mounting on a vehicle.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an automatic transmission. 
2. Related Art 
A conventional automatic transmission changes speeds automatically, in 
accordance with the running conditions. In a gear type automatic 
transmission, for example, a given gear stage is automatically selected 
and established responsive to a change in a running condition. For this 
purpose, a control system is provided to control the various solenoid 
valves of a hydraulic circuit on the basis of the running conditions 
detected by various sensors and thereby changes the engagement of the 
gears and establishes a new gear ratio. 
The aforementioned control system is packaged as an electronic control unit 
(ECU) and mounted in a vehicular compartment. On the other hand, the 
electronic components such as the solenoid valves and the sensors are 
arranged together with the automatic transmission in the engine housing 
because they must be fixed on the automatic transmission. In prior art 
automatic transmissions, however, a large number of adjustments must be 
made to the automatic transmission and the control system. Specifically, 
the automatic transmission and the electronic control unit are 
manufactured separately and are combined with each other when they are 
mounted on the vehicle. This makes it necessary not only for the automatic 
transmission and the electronic control unit to be adjusted at the 
manufacturing stage, before they are mounted on the vehicle, but also for 
the entire automatic transmission system to be adjusted after mounting on 
the vehicle. Moreover, the automatic transmission and electronic control 
unit are separated by a distance requiring elongated connecting wiring 
which raises the cost and complicates trouble-shooting of the wiring 
system. 
In view of the foregoing, an arrangement as shown in FIG. 2 has been 
proposed. In FIG. 2: reference numeral 11 designates the casing of an 
automatic transmission; numeral 12 an electronic control unit mounted on 
the casing 11; numeral 13 a neutral switch; numeral 14 a cable; numeral 15 
a sensor; and numeral 16 a cable extending into the vehicle compartment 
from control components including a mode switch and an engine controlling 
computer. Incidentally, the electronic control unit 12 and the cable 14, 
and the sensor 15 and the cable 14 are separately connected by connectors 
(not shown). 
Because the electronic control unit 12 is thus mounted on the casing 11, 
the automatic transmission system can be adjusted in its entirety prior to 
mounting on the vehicle. This makes it possible to reduce the number of 
adjustments. Moreover, since the cable 14 between the automatic 
transmission and the electronic control unit 12 is shorter as compared 
with the more conventional arrangement, the cost can be reduced and the 
wiring operation can be simplified. 
If, however, the electronic control unit 12 is mounted in the engine 
compartment, it may become contaminated by muddy water or the like. It is, 
therefore, necessary to provide a seal for the electronic control unit 12 
itself and for the connector connecting the electronic control unit 12 and 
the cable 14. As a result, the number of parts is increased, raising the 
cost. 
SUMMARY OF THE INVENTION 
Accordingly, an object of the present invention is to provide a solution to 
the above-described problems associated with the automatic transmission of 
the prior art. Another object is to provide an automatic transmission 
which requires a smaller number of steps to adjust the automatic 
transmission system in its entirety. Yet another object is to reduce the 
cost, to simplify the wiring operation, to lighten the wiring, to provide 
good seals and to reduce the number of parts. 
In order to achieve the above-specified objects, the present invention 
provides an automatic transmission including a casing housing a 
transmission mechanism therein and having a through hole, a first 
plurality of electronic components mounted exterior to the casing and a 
second plurality of electronic components mounted inside the casing. A 
sealed wire terminal is mounted in the through hole and an electronic 
control unit is housed within the sealed wire terminal. Wire cables serve 
to electrically connect the electronic control unit and the various 
electronic components. 
Moreover, the sealed wire terminal supports the cables and has seal members 
forming seals with the interior and exterior surfaces of the casing. 
In a preferred embodiment of the present invention, the sealed wire 
terminal includes two case elements, each having a connector for 
electrically connecting the electronic control unit with a cable. 
In yet another embodiment of the present invention, the electronic control 
unit is housed within a space defined between the two cases, and the seal 
member(s) seals this space from the exterior of the case.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Embodiments of the present invention will now be described with reference 
to the accompanying drawings. 
In FIG. 1, reference numeral 11 designates the casing of an automatic 
transmission. A first plurality of electronic components A, such as a 
control switch, are mounted on the exterior 7 (located in the upper 
portion of FIG. 1) of the transmission casing 11, and the speed change 
mechanism AT and a second plurality of electronic components B, such as a 
solenoid and a sensor, are mounted in the interior 8 (as located at the 
lower portion of FIG. 1) of the transmission casing 11. 
The transmission casing 11 has a wall 9 with a through hole 21, for 
providing communication between the external and internal electronic 
components, in which is inserted a sealed wire terminal 22. 
This sealed wire terminal 22 is formed of two case elements 24 and 25 made 
of a resin highly resistant to heat and oil. The case element 24 is 
arranged on the outer side of the transmission casing 11, and the case 
element 25 is arranged on the inner side. Further, the case element 24 has 
a flange portion 31 in abutment against the outer surface of the 
transmission casing 11, a recessed portion 32 formed as a bulge extending 
from the flange portion 31 to the exterior of the transmission casing 11 
and a connection portion 33 arranged in the bottom of the recessed portion 
32. The case element 24 is fixed on the transmission casing 11 by means of 
bolts 34 extending through the flange 31. On the other hand, the case 
element 25 is composed of a flange portion 41 in abutment against the 
interior surface of the transmission casing 11, a recessed portion 42 
extending from the flange portion 41 to the interior of the transmission 
casing 11 and a connector 43 mounted in the bottom of the recessed portion 
42. The case element 25 is fixed on the transmission casing 11 by means of 
bolts 44 extending through the flange portion 41. 
When the case elements 24 and 25 are fixed on the casing 11 facing each 
other, a space 36 is defined between the two recesses 32 and 42. In this 
space 36 is housed an electronic control unit 37 in which a control system 
is packaged. This electronic control unit 37 is composed of a ceramic 
board 51 and at least one chip 52 mounted on the board 51. 
Electronic control unit 37 must be electrically connected both to the 
electronic components A exterior to the transmission casing 11 and 
electronic components B located inside the transmission casing 11. 
Thus, the electronic control unit 37 and a cable 35 are electrically 
connected by the connection portion 33, and the electronic control unit 37 
and a cable 45 are electrically connected by the connection portion 43. 
No separate component is required to fix the electronic control unit 37 to 
the sealed wire terminal 22 so that the number of parts can be reduced. 
Electrodes (not shown) are formed at the ends 53 and 54 of the electronic 
control unit 37, and are electrically connected to connectors (e.g. 75 in 
FIG. 3) mounted in connection portions 33 and 43, which correspond to the 
aforementioned electrodes. 
Board fixing guides 61 and 62 protrude from the inner surfaces of the cases 
24 and 25 for guiding the electronic control unit 37 into position and for 
securing it there. 
On the faces of the flange portions 31 and 41 abutting the casing 11 are 
circumferentially arranged seal rings 64 and 65. These seal rings 64 and 
65 serve as sealing means for sealing and isolating the interior space 36 
from the exterior. 
Connection portions 33 and 43 will now be described with reference to FIGS. 
3-5 and with reference to connection portion 43 (connection portion 33 is 
identical). 
In FIGS. 3-5: reference numeral 25 designates the case element; numeral 43 
the connection portion attached to the case element 25; numeral 36 the 
space for confining the electronic control unit 37; and numeral 45 a cable 
for electrically connecting the electronic control unit 37 with electronic 
components (not shown) inside the casing 11. In the connection portion 43 
is mounted a connector 75 having a plurality of electrodes 67, and this 
connector 75 and the cable 45 are connected by means of solder 73. This 
connection between the connector 75 and the cable 45 is enclosed within 
the resin of the case element 25. On the other hand, the individual 
electrodes 67 are made of elastic metal strips having inward projections 
68 and 69. 
Moreover, a plurality of electrodes 55, corresponding to the individual 
electrodes 67, are formed at the end portions 54 of the electronic control 
unit 37. These electrodes 67 and 55 are electrically connected by 
inserting the end portion 54 of the electronic control unit 37 into the 
connector 75. 
Each of the electrodes 55 has a groove 70 which receives the projection 69 
so that it is held in place by the mating fit between the projection 69 
and the groove 70. 
Thus, the automatic transmission and the electronic control unit 37 can be 
arranged in close proximity and combined for mounting on the vehicle. As a 
result, the number of steps required for proper adjustments can be reduced 
because the automatic transmission system can be adjusted as a whole after 
it is mounted on the vehicle. 
Since the automatic transmission and the electronic control unit 37 are 
arranged in close proximity, the cable connecting the two can be shortened 
to lower the cost, simplify the wiring and lighten the assembly. 
Because the electronic control unit 37 is mounted within the space 36, and 
this space 36 is sealed by the seal rings 64 and 65, the electronic 
control unit 37 is protected from contamination by dirty water and the 
like. As a result, the sealing function of the sealed wire terminal 22 can 
be utilized to seal the electronic control unit 37 itself and to seal the 
connector 75, so that the electronic control unit 37 itself and the 
connector 75 need not have additional seal structure. As a result, the 
number parts can be reduced to lower the cost. 
Because the electronic control unit 37 is mounted within the sealed wire 
terminal 22 separate from the other functional components, the other 
function components need not be disturbed when the electronic control unit 
37 is replaced. 
Merely by loosening the bolts 34 to remove the case element 24, the 
electronic control unit 37 can be removed from the space 36, thus 
facilitating replacement of the electronic control unit 37. 
A second embodiment of the present invention will now be described with 
reference to FIGS. 6-8. 
In FIGS. 6-8, numeral 11 designates the casing of an automatic 
transmission. The first plurality of electronic components A, such as a 
control switch, are arranged exterior to (on the upper side of FIG. 1) the 
transmission casing 11, and the speed change mechanism AT and the second 
plurality of electronic components B, such as a solenoid or a sensor, are 
arranged on the interior (lower side of FIG. 1) of the same. 
In the transmission casing 11 there is formed a through hole 21 for 
providing communication between the exterior and interior of the casing at 
a predetermined location in the casing 11. In this through hole 21, is 
mounted sealed wire terminal 22. 
Sealed wire terminal 78 is formed of two case elements 79 and 80 made of a 
resin highly resistant to heat and oil. Case element 79 is mounted 
abutting the casing 11, and case element 80 is mounted on case element 79. 
Case element 79 is composed of a flange portion 81 which is mounted in 
abutment against the outer surface of the casing 11, a recessed portion 82 
forming a bulge extending from the flange portion 81 and a connector 
portion 83 formed in the bottom of the recessed portion 82. On the other 
hand, the case 80 is composed of a flange portion 84 which is mounted in 
abutment against the outer surface of the flange portion 81, a recessed 
portion 85 forming a bulge extending from the flange portion 84 toward the 
exterior of the casing 11 and a connection portion 86 formed in the bottom 
face of the recessed portion 85. The case elements 79 and 80 are fixed to 
the casing 11 by means of bolts 88 extending through the flange portions 
81 and 84. 
When the case elements 79 and 80 are fixed on the casing 11, a space 89 is 
defined by the two recessed portions 82 and 85. This space 89 houses an 
electronic control unit 37 in which a control system is packaged. 
As in the previous embodiment, the electronic control unit 37 must be 
electrically connected to both the electronic components exterior to the 
casing 11 and the electronic components arranged inside the casing 11. 
Thus, the electronic control unit 37 and a cable 35 are electrically 
connected by the connection portion 86, and the electronic control unit 37 
and a cable 45 are electrically connected by the connection portion 83, so 
that the electronic control unit 37 is held between connection portions 83 
and 86. 
Electrodes 91 and 92 are formed at the end portions 53 and 54 of the 
electronic control unit 37 and mate with connectors 93 and 94 mounted in 
connection portions 83 and 86. 
Board fixing guides 61 and 62, for guiding the electronic control unit 37 
into position and fixing it there, protrude from the inner surfaces of the 
case elements 79 and 80. 
A seal ring 96 is arranged around the circumference of the flange portion 
81. The seal ring 96 has a section defining a groove 97 opening at its 
inner circumference, and the flange portion 81 is formed with an annular 
protrusion 98 which fits within the groove 97. In the flange portion 84, 
there is formed an annular holding portion 99 which extends radially 
outward of the flange portion 81. As best seen in FIGS. 7, when the flange 
portions 81 and 84 are fixed on the casing 11 by the bolts 88, the seal 
ring 96 is compressed against the exterior surface of the casing by the 
holding portion 99 to thereby form a seal between the flange portion 81 
and the casing 11, and the flange portion 81 and the flange portion 84. As 
a result, the seal ring 96 can seal not only the space 89, but also the 
through-hole of the casing 11. 
The automatic transmission is mounted within limited space in the engine 
compartment. Because the sealed wire terminals 22 (as shown in FIG. 1) and 
78 (as shown in FIG. 6) protrude from the exterior of the casing 11, they 
may interfere with the other parts such as the battery. Thus, a third 
embodiment, as depicted in FIG. 9, is provided to cope with such a 
situation. In this third embodiment, the electronic control unit 37 and 
the casing 11 are arranged in parallel. In FIG. 9, reference numeral 11 
again designates the casing of an automatic transmission. A through-hole 
21 provides communication between the exterior 7 and interior 8 of the 
transmission casing 11 and a sealed wire terminal 108 is mounted in the 
through-hole 21. 
This sealed wire terminal 108 is formed of two case elements 109 and 110 
made of a resin highly resistant to heat and oil. The case element 109 is 
mounted flush against the transmission casing 11, and the case element 110 
is mounted on case element 109. 
When the case elements 109 and 110 are fixed together on the case 11 by 
means of bolts 111, a space 112 is formed therebetween. In this space 112 
is mounted the electronic control unit 37 in which the control system is 
packaged. 
Since the electronic control unit 37 and the transmission casing 11 are 
arranged in parallel, the sealed wire terminal 108 protrudes less from the 
exterior 7 of the transmission casing 11. As a result, the sealed wire 
terminal 108 and other parts, such as the battery, do not interfere with 
each other. 
Further, in FIG. 9, reference numerals 34 and 45 designate cables, numeral 
121 designates an O-ring, forming a seal for the case 109 and the casing 
11, and numerals 122 and 123 designate seal rings, i.e. sealing means, for 
sealing the case elements 109 and 110. 
The invention may be embodied in other specific forms without departing 
from the spirit or essential characteristics thereof. The present 
embodiments are therefore to be considered in all respects as illustrative 
and not restrictive, the scope of the invention being indicated by the 
appended claims rather than by the foregoing description, and all changes 
which come within the meaning and range of equivalency of the claims are 
therefore intended to be embraced therein.