Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2002-03-19
2003-07-08
Martin, David (Department: 2841)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C439S198000, C439S913000
Reexamination Certificate
active
06590777
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a control unit incorporating a pressure sensor mounted to a printed circuit board which is housed in the control unit.
BACKGROUND OF THE INVENTION
An example of detecting a pressure within an intake passage of a throttle body using a pressure sensor is disclosed in Japanese Utility Model Laid-Open Publication No. HEI-3-122246 entitled “Engine Intake System.” This pressure sensor is shown in
FIGS. 6 and 7
hereof.
FIG. 6
illustrates an electronic control unit
101
incorporated in a throttle body
100
.
The throttle body
100
includes a pressure sensor
102
. The pressure sensor
102
has a pressure intake port
103
communicating with a pressure chamber
104
. The pressure chamber
104
communicates with an intake passage
106
via a pressure passage
105
. The pressure sensor
102
detects the pressure downstream of a throttle valve
107
. The electronic control unit
101
controls the operating parameters of an engine (not shown), based on information on the pressure detected by the pressure sensor
102
. The incorporation of the electronic control unit
101
in the throttle body
100
allows the pressure passage
105
to be formed within the throttle body
100
.
In some cases, however, the electronic control unit
101
cannot be disposed in the vicinity of the throttle body
100
because of constraints on layout, for example. An example of such a case is described with reference to FIG.
7
.
FIG. 7
shows an electronic control unit
111
disposed separately from a throttle body
110
.
The electronic control unit
111
has a case
112
and a printed circuit board
113
provided within the case
112
. A pressure sensor
114
is mounted on the printed circuit board
113
. The pressure sensor
114
is connected to a hose connection
116
via a pressure-resistant hose
115
.
A pressure hose
117
is connected to the hose connection
116
provided at a front end
112
a
(right end in the figure) of the case
112
. The pressure hose
117
is communicated with an intake passage
118
of the throttle body
110
(downstream from a throttle valve
118
a
). A harness
120
is connected to a connecter
119
provided at a rear end
112
b
(left end in the figure) of the case
112
. The electronic control unit
111
is connected to a battery and an actuator for controlling an engine.
The pressure sensor
114
detects the pressure in the intake passage
118
downstream from the throttle valve
118
a
. Based on information on the pressure detected by the pressure sensor
114
, the electronic control unit
111
controls the actuator and controls the operating parameters of the engine.
However, the necessity of connecting the pressure sensor
114
of the electronic control unit
111
to the hose connection
116
via the pressure-resistant hose
115
results in an increased number of components.
In addition, the necessity of connecting one end of the pressure-resistant hose
115
to the pressure sensor
114
and connecting the other end of the pressure-resistant hose
115
to the hose connection
116
results in time-consuming assemblage and installation of the electronic control unit
111
.
The increased number of components and the time-consuming assemblage and installation have prevented cost reduction of the electronic control unit
111
.
To connect the harness
120
to the connector
119
provided at the rear end
112
b
of the case
112
requires supporting the case
112
with the right hand while connecting the harness
120
to the connector
119
with the left hand.
Also, the connection of the pressure hose
117
to the hose connection
116
provided at the front end
112
a
of the case
112
requires passing the case
112
to the left hand to connect the pressure hose
117
to the hose connection
116
with the right hand.
The necessity of passing the case
112
from the left hand to the right hand for connecting the pressure hose
117
after connecting the harness
120
results in the time-consuming assemblage and installation of the electronic control unit
111
.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a control unit incorporating a pressure sensor with a simplified and easy-to-assemble construction.
According to an aspect of the present invention, there is provided a control unit incorporating a pressure sensor, which comprises: a case body with an opening; a printed circuit board housed in the case body; a pressure sensor mounted on the printed circuit board and having a pressure intake pipe for taking in pressure from the outside; and a lid to close the opening of the case body, wherein the pressure intake pipe extends toward the lid, and the lid is integrally provided with a first pressure passage to which the pressure intake pipe is fitted, and a second pressure passage extending from the first pressure passage to the outside.
It is thus possible in the present control unit to fit the first pressure passage to the pressure intake pipe to communicate the pressure intake pipe with the second pressure passage via the first pressure passage, by placing the lid over the case body. This eliminates the need for a conventionally-used connecting hose, reducing the number of components to provide a simplified construction and thereby reduce the cost. Also, this saves the trouble of coupling the first pressure passage and the pressure sensor with a connecting hose, resulting in simplified assemblage.
In the present control unit, the case body has a box-like shape, and a connector box provided at one wall of four sidewalls of the case body, and the second pressure passage formed with the lid are oriented in the same direction. Thus the operation of connecting a harness to the connector box and the operation of connecting a pressure hose to the second pressure passage can be done from the same direction. That is, it is possible to connect the harness to the connector box with one hand while holding the control unit with the other hand and thereafter, without changing the hand holding the control unit, to connect the pressure hose to the second pressure passage. Further, the total length of the control unit can be made shorter as compared with a case where the connector box and the second pressure passage are oriented in opposite directions. This increases the degree of freedom in mounting space and facilitates the handling of the control unit during transportation.
In the present invention, the pressure sensor is disposed in the vicinity of the connector box. The thickness of the pressure sensor is generally greater than that of other resistive elements or the like on the printed circuit board. The thickness of the connector box is also generally greater than that of a plurality of control circuit components mounted on the printed circuit board. The maximum thickness of the control unit is determined by the thickness of the pressure sensor and the connector box. Technical difficulties in molding the lid increase as the second pressure passage integrally molded with the lid becomes longer. Under these considerations, the pressure sensor is disposed in the vicinity of the connector box. Such an arrangement of the pressure sensor and the connector box as the determinants of the maximum thickness of the control unit results in only a single portion of the control unit having a relatively large thickness. This facilitates the designing of the control unit. The disposition of the pressure sensor in the vicinity of the connector box makes the first pressure passage positioned above the pressure sensor, and shortens the second pressure passage communicating with the first pressure passage and extending in the same direction as the connector box. This also reduces the diameter of the second pressure passage, resulting in reduced technical difficulties in molding the lid.
An injection opening for the injection of molding resin into the control unit is provided in a corner of the lid in the most distant position from the pressure sensor. Since the pressure sensor has a large thickness as described above
Anma Tomosada
Morino Yuichi
Ogawa Sumitaka
Keihin Corporation
Martin David
Merchant & Gould P.C.
Phan Thanh S.
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