JPH053951Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field: The present invention relates to an improvement of a knock sensor for an internal combustion engine.

Problems to be Solved by Conventional Technologies and Ideas As shown in Fig. 5, the conventional knock sensor for internal combustion engines has a passage for the engine bolt 1 fixed to the cylinder head in the center and a flange 2 in the lower part. The parts of the annular electrode plate 4, piezoelectric element 5, electrode plate 4', insulating plate 6, weight 7, and disc spring 8 are sequentially stacked and fitted on the outer periphery of the provided annular sleeve 3 and on the flange 2, Hold the laminated part with the nut 9
A sensor main body 1 is screwed together and each part is covered with a cover tube 10 such as a resin mold along with the outer periphery of a flange 2.
1 and a part thereof is integrally provided with a signal extraction part 15 including an electrical connection member 14 consisting of an electric wire 12 and a terminal 13 connected to the electrode plate 4 of the sensor main body 11. Therefore, when the knock sensor configured as described above is fastened to the cylinder head 21 of an internal combustion engine with the engine bolt 1, the signal extraction portion 15 rotates integrally with the sensor body 11 due to the rotational moment during installation, and the signal extraction portion 15 rotates integrally with the sensor body 11. There was a problem in that the position of the portion 15 was displaced from a predetermined position, making it difficult to connect to a signal carrying cable extending from the knocking circuit. Furthermore, when the electrical connection member 14 of the signal pull-out section 15 is made of a long lead wire 22 instead of a connector, there are problems in that the lead wire may be twisted, or tensile stress may be applied to the lead wire, resulting in an accident in which the lead wire is pulled out. .

Means for solving the problems: This proposal is a proposal to improve such conventional drawbacks. In other words, the knock sensor of the present invention is fastened to the seat surface of an engine bolt and converts the knocking vibration of the engine into an electrical signal. It consists of a separate structure consisting of an annular sensor body formed with a through hole that exposes the outer peripheral edge of the plate, and a signal extraction part formed by embedding a conductive member in the main part of an annular insulating clipper. A device that is rotatably fitted onto the outer surface of the cover tube of the sensor body, and one end of the conductive member is in electrical contact with the outer periphery of the electrode plate through the through hole of the cover tube of the sensor body. It is.

Embodiments: Examples of the present invention will be described below based on FIGS. 1, 2 and 3, A and B. Note that parts that are the same as those shown in FIG. 5, which is a conventional example, will be described with the same reference numerals. In the figure, an engine bolt 1 is inserted into a cylinder head 21, a sleeve 3 having a flange 2 at the bottom, and a flange 2 fitted around the outer circumference of the sleeve 3.
The electrode plate 4, piezoelectric element 5, electrode plate 4' insulating plate 6, weight 7, and disc spring 8 stacked on top are screwed together with a holding nut 9, and each part is attached together with the flange 2 to a cover tube 10 made of resin mold or the like. The structure of the annular sensor body 11 covered with is the same as that shown in FIG. 5 as a conventional example. When knocking vibration occurs in the engine, the sensor with this structure vibrates the weight due to its inertia, causing distortion in the piezoelectric element and inducing an electric signal proportional to the magnitude of the knocking vibration.

The improvement in this case is that, as shown in FIG.
is made into a separate body, and the signal extraction part 15 is rotatably connected to the sensor main body 11. That is, a through hole 16 for exposing the outer peripheral edges of the electrode plates 4, 4' is formed around the lower part of the cover tube 10, and a groove 17 for rotatably fitting the insulating clipper 18 outside the hole 16 is formed. On the other hand, the signal extracting section 15 has a structure including an annular insulating clipper 18, a conductive sliding member 19 buried in an overhang protruding from the side thereof and protruding inwardly, and an electric wire 12 and a terminal 13 connected to the conductive sliding member 19. An electrical connection member 14 is provided. The conductive sliding materials 19, 19 pass through the through hole 16 of the cover tube 10 to the electrode plates 4, 4', respectively.
The insulating clipper 18 is rotatably fitted into the outer circumferential groove 17 of the cover tube 10 so as to contact the outer circumferential edges 4a, 4a' of the cover tube 10. Although the terminal 13 of the insulating clipper 18 uses a connector 20 type, a lead wire 22 may be used as shown in FIG.

Further, in the present invention, the structure of the sensor main body is not particularly limited, and it is sufficient that the sensor main body has an annular shape for inserting an engine bolt and has at least a piezoelectric element that converts knocking vibration into an electric signal.

Effects and Effects: According to the present invention, since the signal extraction part is rotatably coupled to the sensor body, the signal transmission cable can be connected to the signal extraction part from any position. In addition, products with long lead wires in the signal pull-out part have the advantage that the signal pull-out part does not displace from a predetermined position due to rotation during installation, so there is no risk of the lead wires being twisted or pulled out due to tension. be.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view of an embodiment of the knock sensor for internal combustion engines of the present invention, FIG. 2 is a horizontal sectional view thereof, FIG. 3 A is a perspective view of the sensor body, and FIG.
Figure 9 is a perspective view of the signal extraction section, Figure 4 is a vertical sectional front view showing a state in which lead wires are connected, and Figure 5 is a vertical sectional front view of a conventional knock sensor. 1... Engine bolt, 4, 4'... Electrode plate, 5...
...piezoelectric element, 11...sensor main body, 14...electrical connection member, 15...signal extraction part.

Claims (1)

[Scope of utility model registration request] The outer circumferential edge of the electrode plate is attached to the outer surface of the cover tube, which is fastened to the seat surface of the engine bolt and converts the knocking vibration of the engine into an electrical signal. It has a separate structure consisting of an annular sensor body formed with an exposed through hole and a signal extraction part formed by embedding a conductive member in the main part of an annular insulating clipper. The internal combustion sensor is rotatably fitted onto the outer surface of the sensor, and one end of the conductive member is in electrical contact with the outer periphery of the electrode plate through a through hole in the cover tube of the sensor body. Engine knock sensor.