JPH04194638A - Pressure sensor - Google Patents

Abstract

PURPOSE:To simplify injection of pressure transmitting solution by forming a transmitting solution injection port for injecting the pressure transmitting solution into a case and also providing a screw for sealing the pressure transmitting solution on the transmitting solution injection port. CONSTITUTION:A case 20 is equipped with an oil injection port 1 for injecting silicon oil 29 as pressure transmitting solution into a through hole 20b, while screw 2 is attached to the injection port 1. When the silicon oil 29 is to be sealed in the through hole 20b between a diaphragm 21 and a pressure sensing part 27, after the silicon oil 29 is injected from the injection port 1, the screw 2 is attached to the injection port 1 and the injection port 1 is sealed by adhesive agent 4. Thus injection of the pressure transmitting solution into the case can be simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pressure sensor in which a pressure transmitting liquid is sealed between a pressure sensing portion and a diaphragm.

[Conventional technology]

FIG. 2 is a longitudinal sectional view showing an example of a pressure sensor conventionally used to detect the pressure inside the combustion chamber of an engine.
20 is a stainless steel case that is attached to the engine with a screw portion 20a, 21 is a metal diaphragm provided at the lower end of the case 20 having a through hole 20b formed along the axial direction, and 22 is a case that is attached to the case with a screw 23. 20
It is a cover that is fixed to the

24 is a can-shaped pressure sensor section housed in the case 20;
5 is a head, 26 is a nipple part connected to the head 25, 2
Reference numeral 7 denotes a pressure sensing section consisting of a silicon semiconductor strain gauge bonded to a ceramic pedestal 28, and a high boiling point silicone oil 29 is sealed between the pressure sensing section 27 and the diaphragm 21 as a pressure transmission fluid. ing.

30 is a substrate, 31 is a plate fixed to the substrate 30, 3
2 is installed through the plate 31 and has a pressure sensing portion 27 at the tip.
33 is an output wire welded to the end of the plate 31 by soldering, 34 is a holder for holding the can-shaped pressure sensor section 24 inside the case 20 and the cover 22, 35.36 is a This is an O-ring and a backup ring disposed between the case 20 and the nipple portion 26.

In the pressure sensor configured as described above, the diaphragm 21 is deformed due to an increase in pressure within the combustion chamber, and the pressure within the silicone oil 29 increases with the deformation, and the pressure detection section 27 detects the increased pressure.

In this pressure detection section 27, an electric signal corresponding to the pressure change is outputted to the outside via an output line 33 via a lead wire 32 and a plate 31, and the ignition timing of the spark plug is controlled according to the combustion state in the combustion chamber. Ru.

[Problem to be solved by the invention]

In the conventional pressure sensor configured as above,
Silicone oil 29 is applied to the diaphragm 21 and the pressure sensing part 2
The conduction hole 20b between the diaphragm 21 and the diaphragm 7 is sealed in the nipple part 26, but the silicone oil 29 must be filled in when the can-shaped pressure sensor part 24 is assembled into the case 20, or when the diaphragm 21 is inserted into the case 20. This has to be done when attaching it to the lower end, which poses a problem in that the workability is poor and internal pressure is generated within the case 20 during the work.

This invention has been made to solve these problems, and it improves the workability of sealing the pressure transmission fluid between the diaphragm and the pressure sensing part, and also improves the workability of sealing the pressure transmitting fluid between the diaphragm and the pressure sensing part, and also provides a pressure sensor that does not generate internal pressure within the case. The purpose is to obtain.

[Means to solve the problem]

The pressure sensor of the present invention has a transmission fluid injection port formed in the case for injecting pressure transmission fluid into the case, and a screw for sealing the pressure transmission fluid into the transmission fluid injection port. be.

[Effect]

In this invention, the work of injecting the pressure transmission fluid into the case can be accomplished by injecting the pressure transmission fluid from the transmission fluid injection port, and then screwing the transmission fluid injection port with a screw.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, and the same or corresponding parts as in FIG. 2 are designated by the same reference numerals, and the explanation thereof will be omitted.

In the figure, 1 is an oil inlet which is a transmission fluid inlet leading to the conduction hole 20b, 2 is a screw screwed into the oil inlet 1, 3 is a washer, and 4 covers the head of the screw 2 and injects silicone oil 29. This is an epoxy adhesive for sealing.

In the above pressure sensor, the silicone oil 29 is passed through the conduction hole 20b between the diaphragm 21 and the pressure detection section 27.
The sealing operation for sealing inside the Nira Al part 26 is performed by injecting silicone oil 29 through the oil inlet 1, then screwing the screw 2 into the oil inlet 1, and sealing the oil inlet 1 with adhesive 4. do it.

In the above embodiment, a pressure sensor for detecting the pressure inside the combustion chamber of an engine has been described, but it goes without saying that the pressure sensor of the present invention can be applied to other applications. In addition, silicone oil 29 is used as a pressure transmission fluid.
was used, but other liquids with high boiling points may be used.

C. Effects of the invention] As explained above, according to the pressure sensor of the invention,
The pressure transmission fluid can be injected into the case by simply injecting the pressure transmission fluid through the transmission fluid inlet, then screwing the transmission fluid inlet into the case, which simplifies the process of injecting the pressure transmission fluid. In addition, there is an effect that no pressure is generated inside the case during the work.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view showing an example of a conventional pressure sensor. In the figure, 1 is an oil inlet, 2 is a screw, 20 is a case, 20b is a through hole, 21 is a diaphragm, 27 is a pressure sensing portion, and 29 is silicone oil. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A pressure sensor comprising: a diaphragm provided in a case; a pressure sensing portion provided in the case and directed toward the diaphragm; and a pressure transmission fluid sealed between the pressure sensing portion and the diaphragm. A transmission fluid inlet for injecting the pressure transmission fluid into the case is formed in the case, and a screw for sealing the pressure transmission fluid is screwed into the transmission fluid inlet. pressure sensor.