Knock sensor

• US 20070113618A1
• Filed: 02/24/2006
• Published: 05/24/2007
• Est. Priority Date: 11/22/2005
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Yokoi, Akito, Shibata, Harumasa
• Granted Patent: US 7,614,277 B2
• Time in Patent Office: Days
• US Class Current: 73/35.10
• CPC Class Codes: G01L 23/222 using piezoelectric devices

Abstract

A knock sensor includes: a base made up of a flange portion, and a tube portion; a sensor main body including a piezoelectric element that is fitted over an outer peripheral portion of the tube portion; and a stopper ring that is fitted over the outer peripheral portion of the tube portion and cooperates with the flange portion to clamp the sensor main body, a groove being formed on the outer peripheral surface of the tube portion, and the knock sensor being fixed by driving a pressing jig into an outer peripheral surface of the stopper ring to plastically deform the stopper ring and press a protruding portion into the groove, wherein: an axial length of a recess portion that is formed simultaneously on the outer peripheral surface of the stopper ring when the protruding portion is formed is longer than an axial length of the groove.

Claims

1. A knock sensor comprising:

a base made up of;

a flange portion; and

a tube portion extending axially from said flange portion;

a sensor main body including a piezoelectric element that is fitted over an outer peripheral portion of said tube portion; and

a stopper ring that is fitted over said outer peripheral portion of said tube portion and cooperates with said flange portion to clamp said sensor main body,

a groove extending circumferentially being formed on said outer peripheral surface of said tube portion, and said knock sensor being fixed by driving a pressing jig radially inward toward an outer peripheral surface of said stopper ring to plastically deform said stopper ring and press a protruding portion into said groove,

wherein;

an axial length of a recess portion that is formed simultaneously on said outer peripheral surface of said stopper ring when said protruding portion is formed is longer than an axial length of said groove.

2. The knock sensor according to claim 1, wherein:

a relationship between a thickness D1 of said stopper ring and a depth D2 of said groove satisfies a relationship D2≦

D1≦

2D2.

3. The knock sensor according to claim 1, wherein:

an easing process in which C is less than or equal to 0.3 or R is less than or equal to 0.3 is applied to a corner portion near an entrance to said groove.

4. The knock sensor according to claim 1, wherein:

said recess portion has a shape that enlarges toward an open end.