JPH05203483A - Knock sensor - Google Patents

Abstract

PURPOSE:To prevent the invasion of water drop deposited on a connector coupler part from the connector coupler part and wires to the inside. CONSTITUTION:A base stage 1 has a projection part 3 and a screw part 2 and the center of a vibration plate 5 if fixed to the projection part 3. One side of a piezoelectric ceramic element 6 is placed at one side of the vibration plate 5. On the other side of the piezoelectric ceramic element 6, a pad is connected to an electrode. In a hole 4 in the center of the projection part 3 of the base stage 1, a tube is inserted and a potting agent 12a is charged in the tube to constitute a base stage block A. A resin case block B is constituted of a ring 13 provided at the end of a terminal 9. The ring 13 is contacted to the base stage 1 to combine the stage block A and the resin case block B, one end of the terminal 9 is inserted in the tube, the other end is contacted with a wire harness, and the resin case 14 and the wire harness are fixed with the potting agent 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a knock sensor for use in a knock control system of an automobile or the like, for determining whether or not an engine is knocked and performing ignition timing control.

[0002]

2. Description of the Related Art A knock control system for controlling ignition timing by determining whether or not an engine is knocked is used in an automobile or the like. This knock control system detects the vibration of the engine block, detects the presence or absence of knocking from the vibration waveform, and controls the ignition timing to improve fuel efficiency. A knock sensor is used to detect this vibration.

FIG. 10 shows the structure of a conventional knock sensor. First, the configuration of the lower base block will be described.

Reference numeral 1 is a conductive base having a screw portion 2 integrally formed therein, and a truncated cone-shaped projection is integrally formed at the center of the base 1. Reference numeral 4 denotes a hole formed in the center of the base 1. A sleeve 11 made of an insulating material is inserted into the hole 4, and the sleeve 11 is filled with a potting agent 12a. Reference numeral 5 is a metallic diaphragm, and a hole is formed in the center of the diaphragm 5. The diaphragm 5 is fixed to the protrusion 3 of the base 1 by welding. 6 is a piezoelectric ceramic element 6 adhered to one side of the diaphragm 5,
A hole is provided in the center. Reference numeral 10 is an O-ring housed in an annular groove formed on the upper surface of the base 1.

Next, the structure of the upper connector block will be described. Reference numeral 21 is a connector unit made of an insulating material, and a terminal is fixed to the center of the inside of the connector unit 21. The lead portion 9a of the terminal 9 protruding from the lower portion of the connector unit is filled with the potting agent 12b at the joint with the connector unit. Reference numeral 13 is a metal ring fixed to the outer periphery of the lower portion of the connector unit 21.

The base block and the connector block are assembled separately. After that, the lead wire 8 between the piezoelectric ceramic element 6 and the lead portion 9a of the terminal 9 is soldered to connect the terminal 9a to the piezoelectric ceramic element 6 and the diaphragm 5.
Through the hole in the center of the sleeve and insert it into the hole in the sleeve 11. Further, the ring 13 and the base 1 are integrally formed by the entire circumference ring projection welding.

After this is completed, the lead portion 9a of the terminal 9
Is electrically connected to the lead wire 8 and one surface of the piezoelectric ceramic element 6, and the other surface of the piezoelectric ceramic element 6 is electrically connected to the diaphragm 5 and the base 1.

The screw portion 2 of the base 1 is screwed into a screw hole of an engine block (not shown) and is connected to the ground. The terminal 9 is connected to a knocking controller (not shown) through the insulating connector 22.

[0009]

However, in the conventional knock sensor, there is a possibility that water may enter the knock sensor through the fitting portion between the connector unit and the insulating connector.

The present invention is intended to solve such a conventional problem, and provides an excellent knock sensor capable of preventing water droplets adhering to the connector fitting portion from entering from the connector fitting portion and the wire. The purpose is to provide.

[0011]

In order to achieve this object, a knock sensor of the present invention comprises a base having a protrusion and a screw portion, a diaphragm whose central portion is fixed to the protrusion, and a diaphragm. A piezoelectric ceramic element arranged on one surface, and a pad connected to an electrode on the other surface of the piezoelectric ceramic element,
A ring provided with a lead wire joined to a pad, a tube is inserted into a hole at the center of the protrusion, and a potting agent is filled in the tube to form a base portion, and a terminal and a ring provided at one end. The resin case is composed of and, the ring is joined to the base, the base and the resin case are integrated, and one of the terminals is inserted into the tube and the other is joined to the wire harness. And the wire harness is fixed with a potting agent.

[0012]

Therefore, in the knock sensor of the present invention, since the wire harness is subjected to multiple waterproof treatments, it is possible to prevent water droplets adhering to the connector fitting portion from entering the inside from the connector fitting portion and the wire.

[0013]

Embodiments of the knock sensor of the present invention will be described below with reference to the drawings.

FIG. 1 shows a sectional structure of a base block A and a resin case block B of an embodiment, and FIG. 2 shows a state where the structure shown in FIG. 1 is separated into a base block A and a resin case block B. ing. Further, FIG. 3 shows a configuration on a plane, and FIG. 4 shows an external configuration. In the following text and drawings, the same components as those shown in FIG. 10 are given the same reference numerals.

First, the structure of the base block A will be described. In FIGS. 1, 2, and 3, reference numeral 1 denotes a conductive base having a screw portion 2 formed integrally therewith, and a truncated cone-shaped projection is integrally formed at the center of the base 1. 4 is the base 1
Is a hole formed in the center of the sleeve 4. A sleeve 11 made of an insulating material is inserted into the hole 4, and the sleeve 11 is filled with a potting agent 12a. Reference numeral 5 is a metallic diaphragm, and a hole is formed in the center of the diaphragm 5.
The diaphragm 5 is fixed to the protrusion 3 of the base 1 by welding. Reference numeral 6 denotes a piezoelectric ceramic element bonded to one surface of the diaphragm 5, a hole is provided in the center, and a pad 7 is bonded to the other surface. The diameter of the pad 7 is equal to or less than the diameter of the ring projection provided on the upper end of the protrusion 3 before the protrusion 3 and the diaphragm 5 are joined. 10
Is an O-ring housed in an annular groove formed on the upper surface of the base 1. Reference numeral 19 is an annular groove formed on the upper surface of the base 1.

Next, the structure of the resin case block B will be described. Reference numeral 14 is a resin case integrally formed with the wire harness fixing wall 20. A terminal is fixed to the center of the inside of the resin case 14, and the upper part is entirely hollow. The wire rod 34 of the wire harness is placed in the depression.
The shrink tube 32 and part of the shrink tube 31 are fixed. The wire member 34 of the wire harness is fixed by caulking at the upper end of the terminal 9. The contraction tube 31 is fixed to the wire harness fixing wall 20 with a cable tie 17.

A potting agent 12b is filled in a joint portion between the terminal 9 and the resin case 14 which is projected from the upper portion of the resin case 14. Reference numeral 13 is a metal ring fixed to the outer circumference of the lower part. After fixing the wire harness, the potting agent 15 is filled in the entire recess of the resin case 14.

The base block A and the resin case block B thus constructed are individually assembled. After that, the lead wire 8 between the pad 7 and the lead portion 9a of the terminal 9 is soldered, the terminal 9 is penetrated through the central hole of the pad 7, the piezoelectric ceramic element 6, and the diaphragm 5, and the hole of the sleeve 11 is inserted. Insert inside. Also, the ring 13 and the base 1
And are integrated by all-round ring projection welding and completed.

After the completion, the lead portion 9a of the terminal 9
Is connected to the lead wire 8, the pad 7, and one surface of the piezoelectric ceramic element 6, and the surface of the other piezoelectric ceramic element 6 is electrically connected to the diaphragm 5 and the base 1.

The screw portion 2 of the base 1 of the knock sensor thus constructed is screwed into a screw hole of an engine block (not shown) and is connected to the ground. The terminal 9 is connected to the knocking controller via a wire cable.

FIG. 5, FIG. 6 and FIG. 7 show the structure of this wire cable. 41 in FIGS. 5, 6 and 7.
Is a connector housing, inside which a terminal 40,
A connector seal 39 and a rubber plug 42 are arranged. There are two terminals 40, one of which is connected to the core wire 33 and the other of which is connected to the shield wire 35.
Reference numeral 37 denotes a solder sleeve, which covers the exposed portion of the wire of the shielded wire 35. Reference numeral 32 denotes a shrink tube to which an adhesive is applied, which covers the solder sleeve 37 and the shrink tube 31. Reference numeral 31 is a contraction tube covering the core wire 33 and the shield wire 35. 36 is also a contraction tube, and covers the end of the contraction tube 31 and a part of the core wire 33 extending from the end. Reference numeral 34 is a wire rod of the core wire 33. Reference numeral 38 is a contraction tube to which an adhesive is applied inside, and the connector housing 41 and the contraction tube 3 are provided.
It covers part of 2.

Next, another embodiment will be described. FIG. 8 shows the structure relating to the cross section of another embodiment, and FIGS. 9A and 9B show the structure of the diaphragm.

The configuration shown in FIG. 8 is the same except that the configuration of the diaphragm 18 in the configuration shown in FIG. 1 is different, and a description thereof will be omitted.

9 (a) and 9 (b), a hole is formed at the center and the outer periphery is narrowed down at a substantially right angle.

[0025]

As is apparent from the above description, in the knock sensor of the present invention, since the wire harness is subjected to multiple waterproof treatments, the connector fitting portion and the wire material of the water droplets adhering to the connector fitting portion can be removed. It has the effect of preventing intrusion into the interior.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration in an embodiment of a knock sensor of the present invention.

FIG. 2 is a cross-sectional view showing a state in which the base portion and the resin case are separated in the embodiment.

FIG. 3 is a front view showing a configuration relating to the front in the embodiment.

FIG. 4 is a side view showing an external configuration according to the embodiment.

FIG. 5 is a configuration diagram showing a wire cable when the terminal is connected to the knocking controller in the embodiment.

FIG. 6 is a configuration diagram showing a wire cable when the terminal is connected to the knocking controller in the embodiment.

FIG. 7 is a cross-sectional view showing the configuration of the wire cable when the terminal is connected to the knocking controller in the embodiment.

FIG. 8 is a cross-sectional view showing the configuration of another embodiment.

FIG. 9 is a plan view and a cross-sectional view showing the configuration of a diaphragm according to another embodiment.

FIG. 10 is a cross-sectional view showing the configuration of a conventional knock sensor.

[Explanation of symbols]

 1 base 2 screw part 3 protrusion part 4 hole 5 diaphragm 6 piezoelectric ceramic element 7 pad 8 lead wire 9 terminal 9a lead part 9 terminal 10 O (O) ring 11 sleeve 12a potting agent 13 ring 14 resin case 17 cable tie 19 Groove 20 Wire harness fixed wall

Claims (1)

[Claims] 1. A base having a protrusion and a screw portion, a diaphragm whose central portion is fixed to the protrusion, a piezoelectric ceramic element having the diaphragm disposed on one surface, and the piezoelectric ceramic element. A pad connected to the electrode on the other surface of the pad and a lead wire bonded to the pad, and a tube is inserted into the hole at the center of the protrusion, and the tube is filled with a potting agent to form a base. A base portion is configured, and a resin case portion is configured with a terminal and a ring provided at one end, and the ring is joined to the base to integrate the base portion and the resin case portion, A knock sensor, wherein one of the terminals is inserted into the tube, the other is joined to a wire harness, and the resin case and the wire harness are fixed with a potting agent.