Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2001-01-24
2002-10-15
Gandhi, Jayprakash N. (Department: 2841)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S728000, C361S736000, C361S758000, C361S784000, C361S801000, C439S076200
Reexamination Certificate
active
06466447
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electronic control unit having a connector electrically connecting the unit to outside devices and a circuit board on which driving elements and control elements are mounted, and more particularly to such an electronic control unit in which the connector and the circuit board are connected to each other through flexible wires.
2. Description of Related Art
Electronic control units for controlling operation of outside devices based on signals fed to and processed in the control units are generally known. An example of such electronic control units is briefly shown in
FIGS. 17A and 17B
(
FIG. 17A
shows an cross-sectional view, and
FIG. 17B
shows a plan view with an upper plate removed). In this example, a circuit board
40
, on which various components such as control elements
53
, driving elements
55
and passive elements
57
are mounted, and a connector
51
connecting the control unit to outside devices such as actuators and sensors are contained in a casing consisting of an upper case
50
a
and a lower case
50
b.
A plurality of connector pins
51
a
are inserted into through-holes
40
a
of the circuit board
40
and electrically connected to the circuit board
40
.
Another example of conventional electronic control units for use in an automobile vehicle is briefly shown in FIG.
18
. In this example, a circuit board
930
and a connector
935
are contained in a casing
938
, and the connector pins
935
a
are inserted into the circuit board
930
and electrically connected thereto. An I/O circuit
934
having components
936
, an ECT control circuit
932
for electronically controlling a transmission device, an ENG control circuit
933
having components
937
for controlling operation of an engine, and a throttle control circuit
931
for controlling operation of a throttle valve are all mounted on a single circuit board
930
.
There are following problems in both types of conventional electronic control units. When the connector
51
or
935
is changed to another one in order to connect the control unit to different outside devices, an entire circuit board
40
or
930
has to be redesigned even if its function is not changed, because the connector pins are inserted into the circuit board having a circuit pattern printed thereon. The number of connector pins, the shape of the connector or the alignment of the connector pins have to be changed according to the outside devices to be connected to the control unit. In other words, plural circuit boards have to be prepared for matching various connectors even if the function of the circuit board is not changed. In addition, the size of the circuit board has to correspond to the size of the connector to accommodate the connector pins therein, even if a smaller circuit board is enough to cover a required function. In the conventional example shown in
FIG. 18
, which includes several control circuits in a single circuit board
930
, an entire circuit board must be redesigned to change one of the control functions. All of the foregoing situations result in a higher cost in manufacturing the control unit.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an improved electronic control unit in which the design of the circuit board is standardized and simplified. Another object of the present invention is to provide an improved manufacturing method of such an electronic control unit.
The electronic control unit of the present invention is used for controlling operation of various devices. For example, the control unit is mounted on an automobile to control operation of an engine, a transmission device, a throttle valve and other devices. The electronic control unit is composed of a casing, a circuit board on which various electronic components such as transistors and microcomputers are mounted, a connector for electrically connecting the control unit to outside devices and flexible wires such as a flexible printed-circuit sheet connecting the connector and the circuit board. All those components are contained in a single casing. Various signals fed to the control unit from outside devices including sensors are processed in the control unit, and outputs for controlling the outside devices are generated in the control unit based on the processed signals.
The connector and the circuit board are not directly connected but are indirectly connected through the flexible printed-circuit sheet. Accordingly, if the connector is replaced with another type to match outside devices, it is not necessary to redesign the entire circuit board. Further, the casing is designed to be able to mount thereon variously sized circuit boards. Therefore, a circuit board having a desired function is selectively mounted on the same casing. For this purpose, surfaces for supporting variously sized circuit boards may be formed in the casing, or the supporting surfaces may be formed in steps so that each step can support a differently sized circuit board. Further, heat-generating components such as power transistors mounted on the circuit board may be disposed in the casing in contact with a heat-dissipation wall formed in the casing to quickly dissipate the generated heat.
The electronic control unit is assembled in the following manner. First, the circuit board carrying various components thereon and the connector are respectively mounted on the casing. Then, the connector and the circuit board are electrically connected through the flexible printed-circuit sheet. Preferably, one end of the flexible printed-circuit sheet is soldered to the connector before the connector is mounted on the casing, and then the other end of the flexible sheet is soldered to the circuit board after the connector is mounted on the casing. The other end of the flexible sheet is soldered to the circuit board, preferably, at a position where the circuit board is supported by the casing to avoid deformation of the circuit board. Thus, the control unit is efficiently assembled in a simple manner.
The circuit board may be divided into several circuit boards, each corresponding to a respective object to be controlled, e.g., a transmission device, an engine and a throttle valve. Alternatively, the circuit board may be divided into several circuit boards by function, e.g., a circuit board for handling input signals, a circuit board for processing signals and a circuit board for generating outputs. A certain number of variations for each functionally divided circuit board are prepared to cover various requirements, and circuit. boards meeting a particular requirement are selectively mounted on the casing. In this manner, control units meeting a variety of requirements are efficiently manufactured without making major changes in the entire unit.
A signal alignment board having a printed circuit pattern thereon may be interposed between the connector and the flexible sheet, so that the connector and the circuit board are electrically connected through the signal alignment board and the flexible sheet. Circuit crossovers in a circuit pattern formed in the flexible sheet are eliminated by using the signal alignment board. Further, noise-absorbing elements for eliminating noise fed into the control unit from outside may be mounted on the signal alignment board, thereby eliminating other noise-absorbing elements mounted on individual circuit boards.
According to the present invention, the design of the circuit board is standardized, and the electronic control units meeting a variety of requirements are efficiently manufactured at a low cost.
Other objects and features of the present invention will become more readily apparent from a better understanding of the preferred embodiments described below with reference to the following drawings.
REFERENCES:
patent: 4811165 (1989-03-01), Currier et al.
patent: 5362243 (1994-11-01), Huss et al.
patent: 5408383 (1995-04-01), Nagasaka et al.
patent: 547
Hozuka Minoru
Iida Taku
Murowaki Toru
Sahara Fujio
Sanada Kazuya
Denso Corporation
Gandhi Jayprakash N.
Law Offices of David G. Posz
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