JPH052034U - Notting detector - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide a knocking detector having a two-terminal connector unit with a configuration that enables failure diagnosis of the knocking detector and impedance matching. [Structure] A two-terminal connector section (21) is arranged offset from the center of a connector housing (20), and a mounting space (31) is arranged in a synthetic resin housing (20) in a direction opposite to the deviation direction, and the two-terminal connector section (21) is arranged. The ends of the terminals 23a and 23b are exposed in the mounting space 31, and the terminals 23a and
The piezoelectric element 9 and the resistor body 35 are connected in parallel by connecting the resistor body 23b via the resistor body 35.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a knocking detector that electrically detects the occurrence of knocking in an internal combustion engine with a built-in piezoelectric element.

[0002]

[Prior Art]

 A knocking detector that solidifies a mounting case on the cylinder wall of an internal combustion engine, attaches a vibration sensing member consisting of a piezoelectric element to the inner bottom surface of the case with bolts, etc., causes the piezoelectric element to resonate with the occurrence of knocking, and detects that occurrence. It is known.

This knocking detector has a structure in which a male screw that is screwed into a cylinder wall of an internal combustion engine is projectingly provided on a lower surface, and a vibration sensing member using a piezoelectric element is supported on an inner space that opens upward. And a connector housing that is fitted on the mounting case and surrounds an inner space of the mounting case. Further, the connector housing is provided with terminals that are respectively connected to the front and back electrodes of the piezoelectric element. In some cases, a two-terminal connector portion is provided on the upper portion of the connector housing by surrounding the exposed end of the terminal with a peripheral frame portion by creating a fitting gap for a connection plug.

On the other hand, since the knocking detector is attached to the cylinder block of the internal combustion engine and is exposed to a high vibration and high temperature environment, it is necessary to constantly monitor whether or not it is functioning normally. An object of the present invention is to add to the above-mentioned configuration a configuration that enables fault diagnosis of a knocking detector and impedance matching.

[0005]

[Means for Solving the Problems]

 The present invention provides a knocking detector having the above-mentioned two-terminal connector part, wherein the connector part is offset from the center of the connector housing to one side, and a mounting space is formed on the other side of the connector part. The piezoelectric element and the resistor are connected in parallel by exposing the connecting portion extending from both terminals to the space and connecting both connecting portions through a resistor. Is.

[0006]

[Action]

 In this configuration, the resistor and the piezoelectric element form a parallel circuit. Then, by connecting both terminals to an external electronic circuit, the parallel circuit is incorporated into a four-sided bridge, and an unbalanced output of the knocking detector is detected by means such as detecting an unbalanced output of the bridge. It becomes possible to do. In addition, impedance matching can be easily performed by selecting the resistance value of the resistor.

[0007]

【Example】

 A configuration example of the knocking detector of the present invention will be described with reference to FIGS. The knocking detector of the present invention is assembled by a mounting case 1 in which a vibration sensing member 7 having a piezoelectric element 9 is arranged, and a connector housing 20 made of synthetic resin having a connector portion 21 on an upper portion thereof.

The mounting case 1 is made of a metal mounting case having a hexagonal outer periphery having a cylindrical inner hollow portion 2 therein, a fitting seating surface 3 is formed on the inner peripheral surface thereof, and a thin peripheral wall is formed on the peripheral surface. 4 are connected to each other, and a male screw 5 that is screwed into the cylinder wall of the internal combustion engine is further provided on the lower surface of the four. A vibration sensing member 7 is supported on the lower bottom surface of the inner space 2.

The vibration sensing member 7 is formed by bonding a ring-shaped piezoelectric element 9 having electrodes on the front and back surfaces to a thin metal plate 8 having a disc shape, the resonance frequency of which is matched with the knocking frequency. By supporting the center of the thin metal plate 8 on the lower bottom surface of the inner space 2 with bolts 12, the vibration sensing member 7 is supported on the lower bottom surface at a predetermined interval.

The connector housing 20 has a shape in which the outer diameter is substantially matched with the inner diameter of the thin peripheral wall 4, and inside thereof, as shown in FIGS. The output end portions 24a and 24b exposed to the side are projected in parallel, and further, the output end portions 24a and 24b of the terminals 23a and 23b are connected by the rectangular peripheral frame portion 22 which is connected to the connector housing 20 into the connection plug fitting gap. The two-terminal connector portion 21 is configured by generating and surrounding. The two-terminal connector portion 21 is deviated from the center of the connector housing 20 to one side, a fitting recess 30 is formed in the peripheral portion of the other connector housing 20 of the connector portion, and the inside of the fitting recess 30 is provided with a mounting space 31. I am trying.

On the other hand, as shown in FIG. 4, the terminals 23a and 23b have their lower portions branched into U-shapes to form sub-connection end portions 25a and 25b, which extend toward the mounting space 31 side. And is exposed upwards. Further, the other branch portions are projected downward to form main connection end portions 26a and 26b. The terminals 23a and 23b are embedded in the connector housing 20 by insert molding.

The main connection end 26a of the terminal 23a is electrically connected to the surface electrode of the piezoelectric element 9 of the vibration sensing member 7 by the lead wire 33a. The main connection end 26b of the terminal 23b is electrically connected to the inner surface of the mounting case 1 by the lead wire 33b. That is, the back surface electrode of the piezoelectric element 9 is electrically connected to the mounting case 1 side through the metal thin plate 8 and the bolt 12, so that the main connection end portion 26b of the terminal 23b is connected to the back surface electrode of the piezoelectric element 9. Since they are electrically connected, the voltage generated between the front and back electrodes of the piezoelectric element 9 is taken out from the terminals 23a and 23b.

In addition, the antibody 35 is interposed between the sub connecting ends 25a and 25b exposed to the outside in the mounting space 31 by the conductors 36 and 36, and the sub connecting ends 25a and 25b are connected. . As a result, the piezoelectric element 9 is placed in parallel with the resistor 35.

The resistor 35 may be exposed, but in order to prevent electrical failure due to adhesion of moisture or the like, a potting agent is filled in the mounting space 31 so as to fill the resistor, or the resistor is not filled. An insulating cover may be disposed in the mounting space 31 so as to hermetically seal.

By fitting a plug for connecting to a required electric circuit to the two-terminal connector portion 21, the output end portions 24a and 24ba are connected to an external electric circuit, and the piezoelectric elements arranged in parallel are formed. The element 9 and the resistor 35 are incorporated into the electric circuit to form a four-sided bridge or the like. Then, it becomes possible to detect the electrical connection failure of the knocking detector by means such as detecting the unbalanced output of the bridge. In addition, impedance matching can be easily performed by selecting the resistance value of the resistor 35.

[0016]

[Effect of the device]

 According to the present invention, as described above, the two-terminal connector portion 21 is disposed so as to be displaced from the center of the connector housing 20, and the mounting space 31 is disposed in the connector housing 20 in the direction opposite to the displacement direction. By exposing the ends of the terminals 23a and 23b of the two-terminal connector portion 21 to the mounting space 31 and connecting the terminals 23a and 23b via a resistor 35, the piezoelectric element 9 and the resistor 35 are connected. Since the terminals 23a and 23b are incorporated in a required electric circuit, the electrical connection state of the knocking detector can be monitored and the detector can be connected in parallel. It is possible to maintain a good state at all times, and by selecting the resistor 35, it is possible to easily perform impedance matching, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is a plan view of a knocking detector of the present invention.

FIG. 2 is a partially cutaway front view of the knocking detector of the present invention.

FIG. 3 is a vertical sectional side view of the knocking detector of the present invention.

FIG. 4 is a perspective view of a terminal 23a (23b) of the present invention.

[Explanation of symbols]

 1 Mounting Case 7 Vibration Sensing Member 9 Piezoelectric Element 20 Connector Housing 21 Two-Terminal Connector Part 22 Peripheral Frame Part 23a, 23b Terminals 24a, 24b Output Ends 25a, 25b Sub-Connecting Ends 26a, 26b Main Connecting End 30 Fitting Recess 31 Mounting space 35 resistor

Claims (1)

[Claims for utility model registration] A mounting case in which a male screw that is screwed into a cylinder wall of an internal combustion engine is projectingly provided on a lower surface, and a vibration sensing member using a piezoelectric element is supported in an inner space opening upward, A connector housing fitted on the mounting case and surrounding an inner space of the mounting case, and further provided with terminals that are respectively connected to the front and back electrodes of the piezoelectric element in the connector housing,
In a knocking detector in which a two-terminal connector portion is provided on an upper portion of a connector housing by surrounding an exposed end of the terminal with a peripheral frame portion by forming a fitting gap of a connection plug, the connector portion is provided from a center of the connector housing. By displacing to one side, forming a mounting space in the other side of the connector part, exposing the connecting part extending from both terminals in the mounting space, and connecting both connecting parts by interposing a resistor. A knocking detector characterized in that the piezoelectric element and a resistor are connected in parallel.