JPH0338440Y2 - - Google Patents

Description

[Detailed explanation of the idea]

"Industrial Application Field" The present invention relates to a piston formed by joining a ceramic crown and an aluminum skirt. ``Prior Art'' A specific example of joining a ceramic crown and an aluminum skirt is shown in FIG. 3, and will be explained using it. A ceramic crown 1 made of a silicon nitride sintered body such as Si <sub>3</sub> N <sub>4</sub> is comprised of a combustion cylinder part 3 in which a cavity 2 is recessed, and an outward flange 4 protruding from the opening of the cavity 2 of the combustion cylinder part 3 . On the other hand, the aluminum skirt 5 has a cylindrical shape. The ceramic crown 1 and the aluminum skirt 5 are joined by fitting the combustion cylinder part 3 of the ceramic crown 1 into the head part 6 of the aluminum skirt 5, and inserting a metal such as Kovar between the combustion cylinder part 3 and the head part 6. A plastic fluid material 7 is interposed therebetween. In order to sufficiently fix the plastic fluid material 7 between the head part 6 and the combustion cylinder part 3, the head part 6 is brought into contact with the outward flange 4, and a step part 8 is provided on the inner surface of the head part 6, so that the combustion cylinder part Flow grooves 9 are carved on the outer circumferential surface of the plastic flow material 7 of No. 3, and the holding frame 1 of the silicon nitride sintered body is
0 is disposed above the plastic flowable material 7, a presser device 11 equipped with this presser frame 10 is provided so as to be able to move up and down and pressurize the plastic flowable material 7, and a high frequency coil 12 is disposed near the mounting portion of the plastic flowable material 7. do. Heating temperature is 400
The plastic fluid material 7 is heated and pressurized at ~800°C. In addition,
Reference numeral 13 is a seal ring, and 14 is an air injection. "Problems to be solved by the invention" When joining the ceramic crown 1 and the aluminum skirt 5 as shown in FIG. Moreover, there are various drawbacks such as large thermal shrinkage, and since aluminum has a large coefficient of expansion, the gap between the ceramic and aluminum skirt tends to rattle. ``Means for Solving the Problems'' In view of the above-mentioned circumstances, the present invention provides a cast iron ring at the joint between the ceramic crown and the aluminum skirt, which is subjected to high-frequency heating. The strength of aluminum and cast iron at room temperature and high temperature is shown in the table below.

[Table] "Example" A ceramic crown 1 made of a silicon nitride sintered body such as Si ₃ N ₄ has a combustion cylinder part 3 in which a cavity 2 is recessed.
An outward flange 4 is provided protruding from the opening of the cavity 2 of the combustion cylinder section 3. On the other hand, the metal skirt 5 has a cylindrical shape, and a cast iron ring 20 is provided in the center of the head portion 6 by encircling it. The ceramic crown 1 and the aluminum skirt 5 are joined by fitting the combustion cylinder part 3 of the ceramic crown 1 into the head part 6 of the aluminum skirt 5, and by inserting a cast iron ring 20 cast into the combustion cylinder part 3 and the head part 6. A plastic fluid material 21 made of Kovar is interposed between the two. In order to sufficiently fix the plastic fluid material 21 between the head part 6 and the combustion cylinder part 3, the outward flange 4 is brought into contact with the head part 6, and a recess 22 is provided on the inner surface of the cast iron ring 20, so that the combustion cylinder part Flow grooves are carved as necessary on the outer circumferential surface of No. 3 where the plastic fluid material 21 is attached, and a holding frame 10 made of silicon nitride sintered body is disposed above the plastic flowing material 21, and this holding frame 10 is provided. A presser device 11 is provided so as to be able to move up and down and pressurize the plastic fluid material 21, and a high frequency coil 12 is placed near a portion where the plastic fluid material 21 is attached. The plastic fluid material 21 is heated and pressurized at a heating temperature of 400 to 800°C. ``Effects of the invention'' As mentioned above, the present invention uses a cast iron ring that is susceptible to high-frequency heating to coexist with the fixing plastic fluid material at the joint between the ceramic crown and the aluminum skirt. Because it is easy to heat, the softening temperature can be easily achieved, and the cast iron ring, which has high strength at high temperatures, buffers the pressure applied to the aluminum skirt during high-temperature pressurization during bonding. This can prevent the occurrence of wobbling in the gap between the aluminum skirt and the ceramic crown.

[Brief explanation of the drawing]

Figures 1 and 2 show specific embodiments of the present invention, with Figure 1 being a longitudinal sectional view, Figure 2 being a plan view of Figure 1, and Figure 3 being a plan view of Figure 1.
The figure is another longitudinal sectional view of the piston that joins the ceramic crown and aluminum skirt. 2... Cavity, 3... Combustion cylinder part, 4... Outward flange, 5... Aluminum skirt, 6... Head part, 21... Plastic flowable material, 20... Cast iron ring.

Claims (1)

[Scope of utility model registration request] The outer periphery of a ceramic crown with a recessed cavity is fitted into the head of a cylindrical aluminum skirt, a plastic fluid material is interposed in the gap between the ceramic crown outer periphery and the head, and the plastic fluid material is heated and pressurized to deform it. 1. A piston comprising a ceramic crown and an aluminum skirt joined together, characterized in that a cast iron ring coexists with a plastic fluid material in the gap between the outer periphery of the combustion chamber and the head part.