Pressure sensor having metallic diaphragm with convexity

• US 6,971,268 B2
• Filed: 03/18/2004
• Issued: 12/06/2005
• Est. Priority Date: 03/28/2003
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Tokunaga, Masatoshi, Baba, Hironobu
• Primary Examiner(s): OEN, WILLIAM L
• Application Number:
  US10/802,729
• Publication Number:
  US 20040187587A1
• Time in Patent Office: 628 Days
• Field of Search: 737/06, 737/15, 737/16, 737/17, 737/18, 737/19, 737/20, 737/21, 737/22, 737/23, 737/24, 737/25, 737/26, 737/27
• US Class Current: 73/706
• CPC Class Codes: G01L 19/0645 using isolation membranes, specially adapted for protection

Abstract

A pressure sensor includes a diaphragm for sealing liquid. The diaphragm includes a plurality of convexities, which are disposed concentrically on the diaphragm. Each convexity has a circular arc cross-section in a radial direction and has a ring shape. The sensor has a configuration factor. The configuration factor is in a range between 2.5 and 3.5. The diaphragm of the sensor has excellent deformability so that detection error of the sensor is reduced.

Claims

1. A pressure sensor comprising:

a diaphragm for sealing liquid,

wherein the diaphragm includes a plurality of convexities, which are disposed concentrically on the diaphragm,

wherein each convexity has a circular arc cross section in a radial direction and has a ring shape,

wherein each convexity has a length of the circular arc representing as L, a height of the convexity representing as H, a width of the convexity in the radial direction representing as W, and a pitch between two adjacent convexities in the radial direction representing as P,

wherein the diaphragm has an effective radius representing as R, and a distance between a center of the diaphragm and a center of the convexity disposed utmost outside of the diaphragm representing as r0, the effective radius of the diaphragm being defined as a radius of a part of the diaphragm applied with pressure,

wherein the sensor has a configuration factor representing as α

, which is defined as;

$\mathrm{\alpha <br><br>}=\left(\frac{L}{H}\right)\times <br><br>\frac{\left(\frac{L}{W}\right)}{P}\times <br><br>\left(\frac{\mathrm{r0}}{R}\right),\mathrm{and}$

wherein the configuration factor is in a range between 2.5 and 3.5.

2. The sensor according to claim 1,

wherein the diaphragm has two convexities.

3. The sensor according to claim 1,

wherein the diaphragm is made of metal, and

wherein the liquid is made of oil.

4. The sensor according to claim 1,

wherein the height of the convexity is in a range between 0.16 mm and 0.28 mm,

wherein the width of the convexity is in a range between 1.3 mm and 1.5 mm, and

wherein the convexity is disposed outside of half of the effective radius of the diaphragm.

5. The sensor according to claim 1,

wherein the effective radius of the diaphragm is about 9.3 mm, and

wherein the sensor is used under comparatively low pressure.

6. The sensor according to claim 1,

wherein the sensor is used for detecting emission gas pressure of a diesel-powered vehicle.