JPH0452887Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a lead wire structure of a detection device for detecting the operating condition of an internal combustion engine.

Prior Art Various sensors are provided to constantly monitor the operating status of an internal combustion engine.

For example, there is an oxygen concentration sensor that is installed in an exhaust gas passage and detects the oxygen concentration in combustion gas.

This is used to detect the oxygen concentration in combustion gas and control the air-fuel ratio of the engine to the optimum value, and its predecessor (Japanese Patent Laid-Open No. 153155/1983)
An explanatory diagram of this is shown in Fig. 1.

The sensor consists of an oxygen concentration ratio measuring element 1, an oxygen pumping pump element 2, and a heater element 3.
Two lead wires 4 are drawn out from each element and connected to a sensor voltage detection circuit 5, a pump current supply circuit 6, and a heater current supply circuit 7.

The pump element 2 for pumping oxygen is supplied with current by the pump current supply circuit 6, and the element 1 for pumping oxygen concentration ratio is supplied with current by the pump current supply circuit 6.
A pump is provided on both sides of the oxygen concentration ratio measuring element 1, which functions as a pump to pump out oxygen in the gap between the circumferential gap and the external atmosphere. An electromotive force is generated between the electrodes, this electromotive force is detected by the sensor voltage detection circuit 5, and an appropriate current is supplied to the oxygen pumping pump element 2 so as to maintain the electromotive force at a certain constant value. The current value corresponds to the oxygen concentration in the atmosphere.

The heater element 3 and the heater current supply circuit 7 are for heating the oxygen concentration ratio measuring element 1 and the oxygen pumping pump element 2 to activate them.

As described above, in the case of the oxygen concentration sensor, each element has six lead wires, two for voltage detection and two for current supply, all of which are made of copper-based wires.

Problems that the invention aims to solve Lead wires used in emission system detection devices have excellent heat resistance and electrical conductivity depending on the usage conditions, as well as high tensile strength, flexibility, and resistance to bending and torsion depending on the handling conditions. It is required to be strong, and even more resistant to trauma.

These conditions are required not only for the exhaust system but also for any detection device that detects the operating state of the engine.

However, when the lead wire is simply made of a copper-based wire as in the past, there are problems with tensile strength, bending, twisting, damage, etc.

For example, if you try to improve the tensile strength using only copper wire, you will need to increase the cross-sectional area (wire diameter) of the wire, and the lead wire will become thicker, resulting in six lead wires like the oxygen concentration sensor mentioned above. If the connector is also pulled out, the connector etc. will be larger.
This conflicts with the layout of the engine room, which aims to be as compact and lightweight as possible.

Also, high tensile strength wires with excellent tensile strength (e.g.
A method of using SUS304 wire (SUS304 wire) is also considered, but the disadvantage is that the conductor wire lacks flexibility, increases conduction resistance, and lacks conductivity.

If you want to increase the strength against bending and torsion, it is effective to reduce the wire diameter and increase flexibility, but if the wire diameter is too small, it becomes vulnerable to external damage and increases cost. It gets expensive.

The present invention was developed in view of these points, and its purpose is to provide a lead wire that has excellent tensile strength, flexibility, bending strength, and torsional strength, is resistant to external damage, and can be made smaller and lighter. It is in.

Means and Effects for Solving the Problems The present invention provides a lead wire for a detection device that electrically detects various physical quantities or conditions indicating the operating status of an internal combustion engine. A thin stainless steel wire is provided around the outer periphery of the nickel coated copper thin wire, and the tensile strength of the nickel coated copper thin wire is an intermediate strength between the copper thin wire and the stainless steel thin wire. It has a lead wire structure.

A thin conductive copper wire is placed in the center, and a thin stainless steel wire that is resistant to trauma and has excellent strength is placed on the outer layer.
The nickel-coated thin copper wire in the middle layer acts as a buffer between the thin copper wire in the center and the thin stainless steel wire in the outer layer, and also assists in the conductivity of the thin copper wire and the tensile strength of the thin stainless steel wire, thereby increasing the wire diameter. Despite being small, lead wires with excellent conductivity and various strengths can be obtained.

Embodiment An embodiment of the present invention illustrated in FIGS. 2 and 3 will be described below.

FIG. 2 is a sectional view of the lead wire according to this embodiment.

A 0.1 mm copper wire runs in the center, six copper/nickel wires 11 of the same diameter surround the copper wire 10, and 30 stainless steel wires 12 of the same diameter are attached around it. A total of 37 stranded wires were coated with 13 ethylene tetrafluoride.

Here, the copper/nickel wire 1 surrounding the central copper wire 10
Reference numeral 1 denotes a copper-based wire material, that is, a nickel-coated copper wire, which is bonded with a weight ratio of copper to nickel of 9:1, and the surrounding stainless steel wire is a soft wire of SUS304.

The outer diameter of the lead wire 4 having such a structure is 1.65 mm.

Conductivity is maintained by the central copper wire 10, and the conductivity is assisted by the surrounding copper/nickel wires 11.

In addition, the copper/nickel wire 11 is the soft copper wire 10 in the center.
and the highly rigid stainless steel 12 on the outside, it acts as a buffer material and also has an auxiliary effect on tensile strength.

The stainless steel 12 is made of soft wire to maintain its flexibility, and by using a large number of wires to ensure tensile strength, bending strength, and torsional strength.

Tetrafluoroethylene 13 is intended to ensure heat resistance, flexibility, bending strength, torsion strength, and the like.

By standardizing the diameters of all the wires, bending and twisting strength is reinforced.

Furthermore, by arranging a relatively soft copper wire 10 on the inside and a highly rigid stainless steel 12 on the outside, the bending strength and torsional strength can be further reinforced.

By arranging the high-strength stainless steel 12 on the outside, it can be made difficult to be cut even if it receives external trauma.

As mentioned above, each type of wire makes use of its own characteristics, and the arrangement of the wires is designed to promote those characteristics.As a result, the overall lead has excellent tensile strength, flexibility, bending strength, and torsional strength, and is resistant to external damage. The wire can be constructed with a diameter as small as 1.65 mm.

For sensors with a large number of lead wires drawn out from the sensor, the problem was that the volume occupied by the lead wires was larger than that of the sensor itself, but as in this example, if each lead wire was thinner, the space would be saved accordingly. This allows for effective use and matches the layout of the engine room.

FIG. 3 shows an example in which the lead wire according to this embodiment is applied to an oxygen concentration sensor.

Reference numeral 20 denotes an oxygen concentration sensor consisting of the oxygen concentration ratio measuring element 1, the oxygen pumping pump element 2, and the heater element 3, and a protector 21 having a plurality of through holes 22 covers the oxygen concentration sensor 20. Oxygen concentration sensor 2
0 is secured.

These oxygen concentration sensor 20 and protector 21 are supported by a shell 23, and a lead wire 25 according to this embodiment, which is drawn out from the element of the oxygen concentration sensor 20, is connected to the inside of the shell 23 and the connecting tube 24 following it. The book is thorough.

Since the lead wire made of copper wire used in the conventional oxygen concentration sensor has a diameter of 2.2 mm, the outer diameter of the joint tube 24 can be made approximately 25% thinner, making it smaller and lighter.

This oxygen concentration sensor is installed so as to protrude above the exhaust gas passage, but since it is small, there is a degree of freedom in its installation position, and it can be placed at the most suitable position.

In addition, it has excellent tensile strength, flexibility, bending strength, and torsion strength, and is resistant to external damage, making layout easier.

The lead wire 4 according to this embodiment can be used not only for the oxygen concentration sensor but also for various sensors, and has a wide range of applications.In particular, the sensor requiring many lead wires can be miniaturized.

Effects of the invention This invention has a conductive thin copper wire in the center, a stainless steel thin wire that is resistant to trauma and has excellent strength in the outer layer, and a middle layer of nickel-coated thin copper wire that connects the thin copper wire in the center with the outer layer. It acts as a buffer for the thin stainless steel wire, and also supports the conductivity of the thin copper wire and the tensile strength of the thin stainless steel wire, so it improves tensile strength, bending strength, and torsional strength while maintaining flexibility. It can be made resistant to external damage, and the lead wire itself can be made thin.
For sensors that require many lead wires,
It can be made smaller and lighter, and the layout can be made easier, making it ideal for lead wires for various detection devices for internal combustion engines.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of an oxygen concentration sensor, Fig. 2 is a sectional view showing the structure of a lead wire according to an embodiment of the present invention, and Fig. 3 is a diagram showing an example in which the same lead wire is applied to an oxygen concentration sensor. be. DESCRIPTION OF SYMBOLS 1... Element for measuring oxygen concentration ratio, 2... Pump element for pumping out oxygen, 3... Heater element, 4... Lead wire, 5... Sensor voltage detection circuit, 6... Pump current supply circuit, 7... heater current supply circuit,
10...Copper wire, 11...Copper/nickel wire, 12...
...Stainless steel wire, 13...Ethylene tetrafluoride, 2
0...Oxygen concentration sensor, 21...Protector, 22...Through hole, 23...Ciel, 24...Joint tube, 25...Lead wire.

Claims (1)

[Scope of utility model registration request] In the lead wire of a detection device that electrically detects various physical quantities or conditions that indicate the operating status of an internal combustion engine, a nickel-coated thin copper wire is placed around the outer periphery of a thin copper wire placed in the center. A lead wire structure for a detection device, characterized in that a stainless steel thin wire is provided around the outer periphery, and the tensile strength of the nickel-coated copper thin wire is intermediate between the copper thin wire and the stainless steel thin wire.