Measuring and testing – Fluid pressure gauge – Diaphragm
Reexamination Certificate
1999-08-09
2001-04-10
Fuller, Benjamin R. (Department: 2855)
Measuring and testing
Fluid pressure gauge
Diaphragm
C073S724000, C361S283400
Reexamination Certificate
active
06212955
ABSTRACT:
TECHNICAL FIELD
This invention relates to a capacitance-type pressure sensor unit adapted to measure a pressure based on a variation in capacitance.
BACKGROUND ART
First of all, a conventional capacitance-type pressure sensor unit which is to be improved by the present invention will be described with reference to FIG.
14
.
The capacitance-type pressure sensor unit shown in
FIG. 14
includes a first insulating substrate
1
having a front surface formed thereon with an electrode (not shown) and a rear surface acting as a pressure sensing surface
1
a
and a second insulating substrate
2
combined with the first insulating substrate
1
to constitute a pressure sensor element
3
. The second insulating substrate
2
has a rear surface provided thereon with an electrode (not shown) in a manner to be opposite to the electrode on the first insulating substrate
1
while being spaced therefrom at a predetermined interval and a front surface
2
a
provided thereon with a first circuit pattern (not shown). The first circuit pattern is electrically connected to the two above-described electrodes arranged in the pressure sensor element
3
. The second insulating substrate
2
is mounted thereon with at least one electric circuit component
4
by soldering. The electric circuit component
4
is constituted by an integrated circuit or the like and electrically connected to the first circuit pattern to carry out processing of an output of the pressure sensor element
3
.
The capacitance-type pressure sensor unit also includes a connector
5
arranged on a side of the front surface
2
a
of the second insulating substrate
2
. The connector
5
includes a connector body or connector housing
6
, which includes a base
6
b
having an end surface
6
a
kept contacted with the front surface
2
a
of the second insulating substrate
2
of the pressure sensor element
3
and provided therein with a circuit component receiving chamber
7
in which the electric circuit component
4
is received. Also, the connector
5
includes a plurality of connection conductors or connector terminals
8
which are supported in the connector body
6
and of which one end is arranged in the circuit component receiving chamber
7
and the other end is externally exposed.
The circuit component receiving chamber
7
of the connector
5
has a circuit board
9
arranged therein in a manner to be spaced at an interval from the front surface
2
a
of the second insulating substrate
2
. The circuit board
9
is arranged in a manner to be interposedly supported between an annular support
10
made of an electrically insulating material and arranged on an outer peripheral edge of the front surface of the second insulating substrate
2
a
and a step
6
c
formed on an inner periphery of the base
6
b
of the connector body
6
. The circuit board
9
is provided thereon with a second circuit pattern (not shown), which is electrically connected to the first circuit pattern on the front surface
2
a
of the second insulating substrate
2
and the connection conductors
8
of the connector
5
. Connection between the connection conductors
8
and the second circuit pattern on the circuit board
9
is carried out by inserting one end
8
a
of each of the connection conductors
8
via each of through-holes formed via the circuit board
9
and soldering the end to a soldering electrode arranged on a rear surface of the circuit board
9
. The circuit board
9
and the first circuit pattern on the front surface
2
a
of the second insulating substrate
2
are electrically connected to each other through electrical connection means
11
such as a flexible printed board or the like. The circuit board
9
thus connected is mounted thereon with electric circuit components
12
a
and
12
b
such as capacitors or the like for removing noise intruding thereinto through the other end
8
b
of each of the connection conductors
8
of the connector
5
by soldering.
The pressure sensor element
3
, the circuit board
9
, the base
6
b
of the connector body
6
and the like are received in a receiving casing
13
made of metal. The receiving casing
13
includes a bottom wall section
13
a
formed with a fluid inlet port
14
through which pressure measured fluid such as gas, liquid or the like of which a pressure is to be measured is introduced into the capacitance-type pressure sensor unit of the illustrated embodiment. The receiving casing
13
also includes a peripheral wall section
13
b
connected at one end thereof to the bottom wall section
13
a
, a cylindrical section
13
c
mounted on a central portion of the bottom wall section
13
a
so as to surround the fluid inlet port
14
and a threaded section
13
d
formed on an outer periphery of a distal end of the cylindrical section
13
c
. The pressure sensor element
3
is received in the peripheral wall section
13
b
of the receiving casing
13
in such a manner that the pressure sensing surface
1
a
is arranged opposite to the bottom wall section
13
a
and so as not to define a large gap between the pressure sensing surface
1
a
and the peripheral wall section
13
b
. The pressure sensing surface
1
a
of the pressure sensor element
3
and the bottom wall section
13
a
are arranged so as to define a fluid chamber
15
therebetween into which the pressure measured fluid is introduced. The peripheral wall section
13
b
has a seal member
16
arranged on a portion of an inner periphery thereof positioned between the pressure sensing surface
1
a
and the bottom wall section
13
a
. The seal member
16
is constituted by an O-ring for sealing the fluid chamber
15
. Also, a seal member
17
is interposedly arranged between the base
6
b
of the connector body
6
and the peripheral section
13
b
of the receiving casing
13
. The seal member
17
is constituted by an O-ring supported in a groove formed on an outer periphery of the base
6
b
. The connector
5
is fixed on the receiving casing
13
by holding the base
6
a
of the connector body
6
in an upper end section
13
e
of the receiving casing
13
by caulking.
In the conventional capacitance-type pressure sensor unit thus constructed, when pressure measured fluid such as gas, liquid or the like is introduced through the fluid inlet port
14
into the fluid chamber
15
, a pressure of the fluid acts on the pressure sensing surface
1
a
of the first insulating substrate
1
of the pressure sensor element
3
. Action of the pressure on the surface
1
a
permits a variation in capacitance between the electrodes arranged opposite to each other in the pressure sensor element
3
. Such a variation in capacitance is converted into a voltage signal by a signal processing circuit constituted of the electronic circuit component
4
or the like. The voltage signal thus obtained is then outwardly transmitted through the connector
5
.
DISCLOSURE OF INVENTION
In the conventional capacitance-type pressure sensor unit constructed as described above, the circuit board
9
is interposedly arranged between the support
10
and the step
6
c
provided on the inner periphery of the base
6
b
of the connector body
6
. The support
10
is supported on the front surface
2
a
of the second insulating substrate
2
of the pressure sensor element
3
and the pressure sensor element
3
is supported through the O-ring
16
on the bottom wall
13
a
of the receiving casing
13
. Such construction of the conventional capacitance-type pressure sensor unit tends to cause a pressure of an increased magnitude to be applied to the circuit board when the base
6
b
of the connector body
6
is mounted in the end
6
d
of the receiving casing
13
by caulking. Such application of an increased pressure to the circuit board may possibly cause damage to the circuit board.
Also, the conventional capacitance-type pressure sensor unit is so constructed that electrical connection between the circuit board
9
and the first circuit pattern on the front surface
2
a
of the second insulating substrate
2
is carried out using the electrical connection m
Motoki Yoshimitsu
Nakao Satoshi
Tanaka Atsushi
Aw-Musse Abdullahi
Fuller Benjamin R.
Hokuriku Electric Industry Co., Ltd.
Rankin, Hill Porter & Clark LLP
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