Pressure sensor

Patent metadata

Field	Value
Publication number	US-9891138-B2
Application number	US-201514836515-A
Country	US
Kind code	B2
Filing date	Aug 26, 2015
Priority date	Aug 27, 2014
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

A pressure sensor including a rod-shaped member, a tubular housing, a variable member and a pressure measuring element. The variable member is entirely disposed within the housing, is connected to the housing and the rod-shaped member, and deforms when the rod-shaped member is displaced relative to the housing along an axial direction. The variable member includes a first portion connected to the rod-shaped member, a second portion connected to the housing, and a bent portion which connects the first portion and the second portion to each other and has a bent shape. A portion of the second portion is a pressure receiving portion which displaces the rod-shaped member in the axial direction when receiving a pressure. The pressure receiving portion of the second portion has a substantially uniform thickness, and the thickness of the pressure receiving portion of the second portion is larger than that of the first portion.

First claim

The invention claimed is:

1. A pressure sensor comprising:
a rod-shaped member extending along an axial direction;
a tubular housing within which the rod-shaped member is disposed in a state where a front end of the rod-shaped member projects therefrom;
a variable member disposed entirely within the housing, connected to the housing and the rod-shaped member, and configured to deform when the rod-shaped member is displaced relative to the housing along the axial direction; and
an element, disposed at a rear side with respect to the variable member and within the housing, for measuring a pressure around the front end of the rod-shaped member on the basis of the displacement, wherein
the variable member includes a first portion connected to the rod-shaped member, a second portion connected to the housing, and a bent portion which connects the first portion and the second portion to each other and has a bent shape,
at least a portion of the second portion is a pressure receiving portion which displaces the rod-shaped member in the axial direction when receiving the pressure,
the pressure receiving portion of the second portion has a substantially uniform thickness, and
the thickness of the pressure receiving portion of the second portion is larger than that of the first portion; and
a clearance is present between an inner peripheral surface of the tubular housing and an entire outer peripheral surface of the second portion.

2. The pressure sensor according to claim 1 , wherein the rod-shaped member is a heater which generates heat when being energized.

3. The pressure sensor, as claimed in claim 1 , wherein
the bent portion is the pressure receiving portion, and
the bent portion has a substantially uniform thickness smaller than the thickness of the pressure receiving portion of the second portion.

4. The pressure sensor, as claimed in claim 1 , wherein
the bent portion is the pressure receiving portion, and
the bent portion has a thickness which gradually decreases from a connection portion with the second portion to a connection portion with the first portion.

5. The pressure sensor, as claimed in claim 1 , wherein
the housing includes, at a front side in the axial direction, a housing body portion and a tubular housing tube portion which is disposed with a gap from an inner wall of the housing body portion and has a rear end connected to the housing body portion,
the variable member is connected to the housing tube portion,
a rear end portion of the variable member extends from the front side of the gap toward the rear side of the gap,
a position of the connection between the housing tube portion and the variable member in the axial direction is a position shifted from a rear end of the gap toward the front side by a predetermined length or a position at the front side with respect to the position shifted by the predetermined length, and
the predetermined length is a length which is 50% of a length of the gap in the axial direction.

6. The pressure sensor, as claimed in claim 1 , wherein the variable member is formed by deep drawing.

7. The pressure sensor, as claimed in claim 1 , wherein an inner peripheral surface of the variable member consists of a surface which extends straight in parallel to the axial direction and a surface which faces rearward of the axial direction.

8. The pressure sensor, as claimed in claim 1 , wherein a step is formed on the outer peripheral surface of the second portion at a boundary between the second portion and the bent portion.

Assignees

• Ngk Spark Plug Co

Inventors

• Hirokawa Toshiki
• Harada Hiroshi

Classifications

• F23Q2007/005

  pressure sensors · CPC title

• F23Q7/001 Primary

  Glowing plugs for internal-combustion engines · CPC title

• G01M15/08 Primary

  by monitoring pressure in cylinders · CPC title