Mitsubishi Denki Kabushiki Kaisha

Fuji Ceramics Corporation

Akito Yokoi

Harumasa Shibata

Masao Kohashi

Keizo Miyake

Hidehiro Inaba

Yoichiro Takahashi

Yoshiyuki Sawada

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.

Knock sensor

A knock sensor of the invention includes a base having a cylindrical part mounted on a vibration generating part and a flange part, an annular piezoelectric element fitted to the cylindrical part and for converting a knocking vibration of the vibration generating part into an electric signal to detect it, electrodes respectively provided to be in contact with both surfaces of the piezoelectric element, terminal plates disposed to be in contact with the respective electrodes and for extracting an output of the piezoelectric element to outside, and a hold unit for pressure holding the piezoelectric element, the electrodes and the terminal plates to the flange part, in which a conductive adhesive material having an almost equal thickness to the electrode is provided on a portion of the piezoelectric element which is not in contact with the electrode.

A knock sensor is constructed by putting and fitting components including an annular piezoelectric element, terminal plate, insulating sheet and weight onto a base consisting of a flange portion and a tubular portion, forming a groove part on a tip outer circumferential surface of the tubular portion, fitting a stopper ring functioning to apply an axial preload to the components onto the tubular portion, and caulking fixedly the stopper ring and the tubular portion into the groove part.

Knock sensor and manufacturing method thereof

A stacked body constituted by a first insulating sheet, a first terminal plate, a piezoelectric element, a second terminal plate, a second insulating sheet, a weight, and a disk spring is fitted over a cylindrical portion of a base, clamped and held between a nut and a flange portion of the base, and resin-molded. Annular partial electrodes having a width narrower than a radial width of the piezoelectric element are formed on front and rear surfaces of the piezoelectric element. The first and second terminal plates have annular portions formed so as to have annular shapes having an outside diameter and an inside diameter substantially equal to those of the partial electrodes, and are stacked such that the annular portions are placed in close contact with entire surfaces of the partial electrodes.

A knock sensor of the invention includes a base having a cylindrical part mounted on a vibration generating part and a flange part, an annular piezoelectric element fitted to the cylindrical part and for converting a knocking vibration of the vibration generating part into an electric signal to detect it, electrodes respectively provided to be in contact with both surfaces of the piezoelectric element, terminal plates disposed to be in contact with the respective electrodes and for extracting an output of the piezoelectric element to outside, and a hold unit for pressure holding the piezoelectric element, the electrodes and the terminal plates to the flange part, in which the electrodes are provided to be in partial contact with the piezoelectric element, and an electric insulating material having an almost equal thickness to the electrode is provided on a portion of the piezoelectric element which is not in contact with the electrode.

There is provided a knocking sensor for an internal combustion engine improved so that electrical damage of a terminal plate in an annular combination member is more certainly prevented. Only two communicating passages separate from each other by substantially 180 degrees are formed in an annular weight of the annular combination member, and resin is filled into an annular space at an inner periphery of the annular combination member by using these two communicating passages. When a passage axis where the two communicating passages are positioned is made substantially orthogonal to a resin injection direction, the resin can be more effectively filled into the annular space.

Knocking sensor for internal combustion engine and manufacturing method of the same

Structure for mounting a knock sensor () on an engine includes the sensor () comprised of an annular main body () and an external connecting portion (). The knock sensor () is secured onto a mounting seat () formed on the engine for detecting vibration thereof transmitted to a piezoelectric element () from the mounting seat () through the main cylindrical metal member (). The mounting structure includes a clamping member () extending through a through-hole () for fixing the main body () on the seat (), an engine-side engaging portion () radially distanced from the axis of the clamping member () and a bearing portion () provided on the sensor () and adapted to engage with the engine-side engaging portion (). The knock sensor can be mounted easily with harness layout design being facilitated because the knock sensor is prevented from rotation upon mounting thereof.

Growing community of inventors

Tokyo, Japan

Akito Yokoi