JPH0140024Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a knocking sensor that detects the knocking state of the engine of an automobile, etc. It has a simple structure with a small number of parts, and can be easily assembled and electrically connected. The present invention provides a knocking sensor.

Knocking of automobiles is considered to be one of the impediments to smooth running, engine durability, and improvement of fuel efficiency. It is known that when such knocking occurs, the knocking can be quickly eliminated by controlling the ignition timing, mixture ratio, etc.

Generally, the knocking sensor detects the knocking condition from the peak of the spectrum generated as the vibration waveform of the automobile engine, and the frequency of the peak changes depending on the type and size of the engine. ~9KPH
exists in Since it is necessary to pick up changes in this spectrum around the car engine, which has a very poor S/N electrically, the sensitivity frequency characteristic of the knocking sensor to vibrations has a sharpness at the above peak frequency, as shown in Figure 1. It is desirable to match the high resonant frequency of the

Further, regarding the sharpness, there is an upper limit to improve the transient characteristics, and a lower limit to make the vibrator have a simple cantilever structure, and it is desirable to set it to 10 to 100.

2 and 3 show a conventional knocking sensor, 52 is a shield wire, 53 is a rubber pushing, 54 is a cap, 55 is a screw, 56 is an element holder, 57 is a ceramic element, 58 is a substrate, 5
9 is a base, and 60 is a housing.

Here, if the screw 55, element holder 56, ceramic element 57, substrate 58, and base 59 are used as a knocking pickup part, the substrate 58, ceramic element 57, and element holder 56 are stacked on the base 59, and the screw 55
Fix it with.

However, the sensor with this structure has a shielded wire 52 and can only be attached to the engine with a manual torque wrench, and an impact wrench cannot be used. Also, its maintenance is troublesome.

Furthermore, although the base 59 is held by the press-fitting of the cap 54, variations in the press-fitting may cause looseness within the housing 59.

The present invention eliminates these drawbacks and will be described below with reference to an embodiment shown in FIGS. 4 to 8. Here, 1 is an O-ring, 2 is a connector, and 3 is a housing with a nut-shaped outer periphery and a screw groove 4 for attachment to the engine at one end, and a sensor section is housed in this housing 3. An annular plane portion 7 is formed on which the hole 5 and the base 11 come into contact. Reference numeral 6 indicates a caulking portion at the open end of the housing 3. 8 is the O-ring, 9 is the regulation ring,
10 is a connector terminal; 11 is a base having an engaging part 111 that engages with the connector 2 on one side, and a hole 112 through which one end of the connector terminal 10 protrudes;
2. Ceramic element 13 and element holder 14 are stacked in this order and fixed to base 11 with screws 15 and 16. A wire 17 electrically connects the substrate 12 and the connector terminal 10. Furthermore, the ceramic element 13
The + output detected by the board 12, the wire 17, the connector terminal 10, the - output detected by the element holder 14, the screw 1
5, 16, the base 11, and the casing 3.

The assembly process in this configuration will be explained. A component including the ceramic element 13 is attached to the base 11 to form a knocking pickup portion in advance, and in this state, one end of the connector terminal 10 of the connector 2 is aligned with the hole 112, and the connector 2 and the base 11 are engaged. let

Next, the base 11 side of the connector 2 holding the base 11 is inserted through the opening of the housing 3, and with the base 11 in contact with the annular flat part 7 inside the housing 3, the O-ring 8 , the fifth
As shown in FIG. 6, the connector 2 and the housing 3 are integrated by caulking the caulking portion 6 of the housing 3.

Since the O-ring 8 is used here, the elasticity of the O-ring 8 allows the connector 2 and the housing 3 to be reliably integrated, while also preventing the inflow of water, etc. from this portion. Note that the hole 112 through which the connector terminal 10 protrudes is sealed with an adhesive or the like with the terminal 10 protruding.

The present invention has the above-mentioned structure, in which the base constituting the sensor pickup section is held at one end of the connector, the base holding section side of this connector is inserted through the opening of the housing, and the connector and the housing are connected. Since the connector is integrated, there is no need to interpose a spacer or the like between the connector and the base, which simplifies the structure with fewer parts and facilitates assembly. Further, according to the present invention, when the base is held by the connector, one end of the connector terminal is made to protrude through the hole in the base, and this protrusion and the ceramic element are electrically connected. Electrical connection work can be easily performed outside the casing and independent of the casing.

[Brief explanation of the drawing]

Fig. 1 is a sensitivity frequency characteristic diagram for acceleration of a knocking sensor, Fig. 2 is a sectional view of a conventional knocking sensor, Fig. 3 is a sectional view taken along A-A thereof, and Fig. 4 is an example of an embodiment of the present invention. A plan view of the knocking sensor, Figures 5 and 6 are enlarged cross-sectional views, and Figure 7 is a plan view of the knocking sensor.
The figure is a sectional view showing the relationship between the connector and the base, and FIG. 8 is a plan view of the base. 2... Connector, 3... Housing, 4... Screw groove,
5... Hole, 6... Caulking part, 7... Holding part.

Claims (1)

[Scope of utility model registration request] A housing having a hole with one end open, a connector having a connector terminal, and a hole through which one end of the connector terminal passes, a ceramic element is supported on one side, and the other side is held at one end of the connector. a base; and a connecting member for electrically connecting one end of the connector terminal passing through a hole in the base to the ceramic element; A knocking sensor in which the housing and the connector are integrated by bringing the housing into contact with each other and caulking an open end of the housing.