JPS59226487A - Spark plug - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spark plug made of +ttL, in which a noble metal tip electrode made of an alloy of a specific composition is arranged in the spark discharge part of the central vehicle inspection or outer fill electrode to form a spark gap.

Conventionally, it has been known that as a method of reducing electrode wear in spark plugs, a heat-resistant and oxidation-resistant noble metal tip electrode is used in the spark discharge section instead of an electrode made of a base metal such as a nickel alloy. A spark plug using a small amount of pi-Ir alloy was proposed, but this spark plug also had problems such as chip peeling under thermal cycle loads of 1000°C to 1100°C or higher, and sparks caused by long-term use. There is a problem with consumability, and a clad structure has been proposed to satisfy spark consumability and peeling stability, but it is expensive in terms of material cost and productivity. .

This invention eliminates the drawbacks of the conventional ones by using a single alloy, and in particular, as an alloy, l)
By using the alloy, we were able to achieve effects that were not available with conventional K.

That is, Figure 1 shows the test results under the conditions of electric αy (CI) I, number of sparks 100 PI) S (4 rus per second), and the vertical axis in the figure shows the amount of gap increase, and the horizontal axis shows the gap increase amount. It shows the time, and according to this, 0.5
The pt2ONi alloy chip in a was worn out in 150 hours, but all the pt-pci alloys had a small amount of wear and could be used satisfactorily.

Furthermore, Fig. 2 shows the Pt-Ir joint rate (~ and Ir = 20
As a comparison sample, a 0.4-gate thin plate of PT20Ir alloy containing M was welded into the recessed part of the alloy base material.
Similarly, we prepared PT 35 PD and PT 15 Pd alloys with 35 weight cracks and 15 weight additions of PD, respectively, and pt2ONi alloys with Ni2O heavy gas and S attack as pt-Ni alloy materials, and the test conditions were as follows. , heating at 1100°C for 1 minute with a burner and heating at 200'C-1'
This test shows the peeling state after 3,000 cycles, with separate cooling as one cycle, and the results of this test are p
Although the 20Ir alloy does not crack, there are gaps throughout the boundary, indicating poor adhesion. , pt15pd alloys all have small gaps and good adhesion, and pt2ONi
Apart from fire resistance and consumability, they are similarly good.

Moreover, Fig. 4 shows the p t - p d alloy material: pt, p
d shows Brinell hardness with respect to the blending ratio, and in the figure, the range a of Pournell hardness of 160 or more - E is a force; it is a good welding range,
Shitakatchi, pd range force of 15 to 60% by weight; indicates that it is a range that can be applied as a chip.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The snow plug of the present invention in which the above-mentioned alloy material is disposed will be described below with reference to illustrated embodiments.

FIG. 3 is a cross-sectional view of the main part of the ignition part of the spark plug of the present invention, (1) is a porcelain insulator made of alumina,
2) is Ni-Si-Cr-Mn, Ni-C
This is a center electrode base material made of an r-Fe-based nickel alloy, which protrudes from the tip end into the shaft hole of the insulator (1) and is fixed according to conventional specifications. (3) is a pt-Pd alloy chip welded by l/e electric welding to the spark discharge surface ('2a) at the tip of the center electrode base material (2), and this alloy material has a pd of 15 to 60 wt. %, the remainder consists of pt.

The thickness of this chip is 0.1 to 1. For example, the disk of Orrrm is formed in the concave hole (2b) at the tip of the center electrode base material (2).
It is embedded and bonded inside. Reference numeral (4) denotes a metal shell for coaxially housing and fixing the insulator, and the tip of the insulator leg protrudes from its annular end surface (4a). (5) is an outer mold (t) with a rectangular cross section formed of a nickel alloy with the same interest as the center electrode base material (2), and is connected to the annular end surface (4a) of the main metal fitting (4) and is attached to the chip. (3) to form a spark gap (7). 1 ()) is formed on the spark discharge surface (5a) facing the central type (i constant) of the outer type (5). The chip (6) is made of the same material P as the above-mentioned chip ff electrode and is made of -15 to 60 gravity 1 modulus PD alloy, and this chip (6) is, for example, the outer electrode base material (5)
It is embedded and bonded in the recess (5b) of.

In addition, as mentioned above, the pi-Ni alloy has good peeling durability, but is inferior in terms of resistance to spark consumption. The electrode is used as the negative polarity side, and the center electrode side has a large amount of wear and tear.), and the opposite electrode (+: the side with less wear and tear) is made of P-t-N.
By using the i-alloy (NilO~60 weight, balance pt), the overall cost can be lowered compared to the case where the pt-pd alloy constitutes both electrodes.

In addition, as stated above, if pt-Ni alloy material contains less than 10% by weight of Ni, sufficient sliding properties cannot be obtained for practical use.
When i is added by 60% by weight, even if the sliding properties are improved, the oxidation resistance is significantly lowered and practicality is lost.

As described above, the spark plug of the present invention has pt-P
By using the d-alloy material chip, it not only has good spark consumption resistance, but also has low cost and fire resistance by forming spark discharge with 1 part PT Ni alloy material which is less affected by spark consumption. This has the remarkable effect of providing a spark plug with good flower wearability and adhesive properties.

[Brief explanation of the drawing]

Figure 1 shows the spark abrasion resistance of the alloy material of the present invention and a comparative alloy, and Figure 21\1 also shows the adhesion to the base material.
FIG. 3 is a sectional view of the main part of the ignition part of this invention, and FIG. 4 is a pt-
The relationship between the Brinell hardness and the PD blending ratio of PD alloys is shown. Patent applicant Representative patent attorney Mitsuru Fujiki ￥ Figure 1 Figure 3 Figure 4 Pd%

Claims (2)

[Claims] (1) A precious metal chip 7゛ is arranged in the spark discharge part that forms the spark gap between the center electrode and the outer 1 electrode, and the precious metal chip is Pd15 to 60% by weight and the rest is Pd% by weight.
A spark plug made of i-,-Pd alloy material. (2) A noble metal chip is placed in the spark discharge part that forms the spark gap between the center electrode and the outer 11L pole, and Pd15 is placed in the spark discharge part on the negative electrode side where spark consumption is a problem.
A Pt-Pd alloy chip consisting of ~60 layers and the remainder r't is attached to the other spark discharge part, N]1θ~60 layers,
41.
” spark plug.