Pressure detection apparatus having first and second cases...

Details Pressure detection apparatus having first and second cases... Pressure detection apparatus having first and second cases...

2000-06-26

2002-12-17

Oen, William (Department: 2855)

Measuring and testing

Fluid pressure gauge

With protective separator

Reexamination Certificate

active

06494099

ABSTRACT:

CROSS REFERENCE TO RELATED APPLICATION
This application is based upon and claims the benefit of Japanese Patent Application No. 11-203568 filed on Jul. 16, 1999, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a pressure detection apparatus including two cases, which are fixedly assembled to form a pressure detection chamber, and to a method of manufacturing the same.
2. Description of the Related Art
JP-A-7-243926 proposes a pressure detection apparatus shown in FIG.
9
. The pressure detection apparatus has a connector housing J
1
as a first housing, and a main housing J
2
as a second housing. The connector housing J
1
and the main housing J
2
are fixedly assembled to form a closed pressure detection chamber J
3
. An internal pressure of the pressure detection chamber J
3
is detected by a pressure sensitive element J
4
, and is output as a sensor output voltage through a connector pin J
5
that is electrically connected to the pressure sensitive element J
4
.
The two housings J
1
and J
2
are fixed together by caulking an opening edge portion J
2
a
of the main housing J
2
from a position indicated by a two dotted line onto the connector housing J
1
. Accordingly, the pressure detection chamber J
3
sealed by an O-shaped ring J
6
is provided. The pressure detection chamber J
3
is filled with oil as a pressure transmittance medium.
In the conventional manufacturing method of the pressure detection apparatus as described above, however, it is difficult to crush the O-shaped ring J
6
uniformly due to variations in caulking load when the two housings J
1
and J
2
are caulked, resulting in variations in volume of the pressure detection chamber J
3
. Because of this, the internal pressure of the pressure detection chamber J
3
varies to cause variations in sensor output voltage (for instance, in a range of 30 mV to 40 mV) with respect to a target value. The variations in sensor output voltage appear as variations in output offset, thereby inhibiting improvement of output sensitivity. These adverse effects are especially prominent when a detecting pressure range is low and the sensor output voltage is small.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above problem. A first object of the present invention is to provide a method for manufacturing a pressure detection apparatus by fixing a first case and a second case to decease variations in volume of a pressure detection chamber. A second object of the present invention is to provide a pressure detection apparatus having a structure, which can be manufactured without producing variations in volume of a pressure detection chamber.
According to a first aspect of the present invention, a pressure detection apparatus is manufactured by assembling a first case and a second case to form a pressure detection chamber closed therebetween and to form a space between an outer surface of the first case and an inner surface of the second case, and by filling the space with adhesive made of resin.
According to a second aspect of the present invention, a pressure detection apparatus has a first case, a second case connected to the first case to form a pressure detection chamber, and to define a space between an outer surface of the first case and an inner surface of the second case, and an adhesive filling the space. Accordingly, variations in volume of the pressure detection chamber can be decreased in comparison with a conventional method by caulking, resulting in decreased variations in output.


REFERENCES:
patent: 4903164 (1990-02-01), Bishop et al.
patent: 5595939 (1997-01-01), Otake et al.
patent: 5932808 (1999-08-01), Hayashi et al.

Affiliated with

Also associated with

Rating

Pressure detection apparatus having first and second cases... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Pressure detection apparatus having first and second cases..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pressure detection apparatus having first and second cases... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2993344