JP2879178B2 - Ceramic push rod and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic push rod for an engine in which cutting after firing is omitted and polishing is minimized, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A conventional ceramic push rod has an elongated shape in which the length of the rod is about 20 to 30 times its diameter, so that it is easily deformed during firing. Therefore, in order to avoid the firing deformation as much as possible, a ceramic material is pressed into a columnar shape, and a hole 20a for a hanging tool is formed in the pressed push rod 20, and as shown in FIG. The hanging tool 21 is inserted and hooked on the sheath 22 of the baking furnace and hung, and the hanging tool 21 is pulled out or, as shown in FIG. 7, the hanging part 21a is hooked on the sheath of the baking furnace. After baking and baking, as shown in FIG.
And, as shown in FIG.
, And then the concave spherical base 24 and the convex spherical base 2
5 was to be polished.

[0003]

However, in this manufacturing method, since the hanging tool 21 is inserted into the hanging tool hole 20a of the push rod 20, and the hooked portion 23 is cut off, the ceramic material is extra by the amount of the hooked portion 23. In addition, since the hooked portion 23 must be cut after firing, and the concave spherical base 24 must be roughly formed by polishing at the end on the cut side, processing time is increased and the cost is increased. Was.

It is an object of the present invention to provide a ceramic push rod and a method for manufacturing the same, which can reduce costs by saving ceramic materials, omitting steps and shortening processing time.

[0005]

In order to solve the above-mentioned problems, a ceramic push rod according to the present invention, when divided into three equal parts in the axial direction, has a convex spherical base and a concave spherical base at a portion excluding a central portion. At least 5 mm away from any of them, a hole for a hanging tool is provided independently and penetrating so as to be orthogonal to the axis, and the manufacturing method of the present invention is such that a ceramic material is cast and spherical bases are provided at both ends. A push rod shape having a near-net shape is formed, a hole for a hanging tool is penetrated through at least one end side of the push rod formed with the near-net shape, and the hanging tool is inserted into the hole for the hanging tool. The push rod is suspended and baked, and after firing, the spherical bases at both ends are polished.

[0006]

When the hole for the hanging tool is divided into three equal parts in the axial direction, the hole excluding the central part is located at a distance of at least 5 mm from both the concave spherical base and the convex spherical base, and is independently and axially separated. Since it is penetrated so as to be perpendicular to, the rigidity, strength and firing deformation are not adversely affected. In addition, a hole for a hanging tool is provided through a push rod in which the spherical portions at both ends are formed in a near net shape by casting, and a hanging tool is inserted into the hole for the hanging tool,
The hanging tool is hooked on the sheath of the firing furnace to fire the push rod, and after firing, the hanging tool is removed, and the near-net-shaped concave spherical base and convex spherical base are simply polished to produce a product. In addition, there is no need to cut the hooked portion or rough-process the concave spherical base by polishing, so that the processing time can be shortened and the cost can be reduced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for manufacturing a ceramic push rod according to the present invention will be described with reference to the drawings. As shown in FIG. 1, an elongated ceramic push rod 1 having a concave spherical base 1a at one end and a convex spherical base 1b at the other end is molded into a near net shape by casting a ceramic material made of sintered silicon nitride, zirconia, or the like. .

A hole 2 for a hanging tool is formed at a position described below so that the rigidity, strength and firing deformation of the ceramic push rod 1 are not adversely affected. It is desirable that the hole for the hanging tool be formed on the base end side as much as possible. When the entire length is at least approximately equal to three, the Z part of the X and Z parts excluding the central Y part, and the convex spherical base part 1b From 5
At a position separated by not less than mm, the hole 2 for a hanging tool is penetrated independently and perpendicular to the axis. Then, as shown in FIG. 2, when the entire length is approximately divided into three equal parts, the hanging tool hole 2 is the X part of the X and Z parts excluding the central Y part,
Further, it may be provided at a position 5 mm or more away from the concave spherical base 1a. When the entire length is divided into approximately three equal parts, the central Y portion is subjected to a high stress during use, and, during firing, a portion protruding above the sheath of the firing furnace is likely to bend.
It is better to avoid providing the hole 2 for the hanging tool.

As shown in FIG. 3, a ceramic bar 3 as a hanger is inserted into the hanger hole 2 of the ceramic push rod 1 formed as described above, and the ceramic bar 3 is inserted into a firing furnace (not shown). The ceramic push rod 1 is hooked to the sheath 4 and fired. After firing, the ceramic bar 3 is removed, and the spherical base 1a and the convex spherical surface 1b, which have been subjected to the near net shape molding, are polished to obtain a product.

[0010] Thus, the ceramic push rod 1
Does not cut off the hooked part after firing,
Compared with the conventional ceramic push rod, the ceramic material can be saved only in the hooked part, and the step of cutting the hooked part and roughing the spherical hole by polishing is omitted compared to the conventional method, The processing time can be shortened, the cost can be reduced, and the weight can be reduced by the through hole for the hanging tool.

The method and the shape of the ceramic push rod and the ceramic bar in the above embodiment and the position where the hole for the hanging tool is provided are merely examples, and the present invention is not limited thereto, and departs from the object and spirit of the present invention. It can be changed appropriately within a range not to be performed. As shown in FIGS. 8 and 9, the same effect can be obtained by providing a stepped portion on the cylindrical end side, but the protruded stepped portion 25 in FIG. Undesirably, the groove-shaped stepped portion 26 as shown in FIG. 9 must be set to a groove depth in consideration of firing shrinkage, and may be shifted from the position set in the sheath 22 during shrinkage. On the other hand, the diameter of the hanging portion must be significantly smaller than the diameter of the outer cylindrical portion, and in a push rod in which the outer cylindrical portion diameter is often set to about φ10, it is not preferable to set the groove as the hanging portion. If the hanging portion is designed as a hole, it is sufficient to select only the diameter of the hanging tool with respect to the hole diameter.

[0012]

As described above, the ceramic push rod according to the present invention has a convex spherical base and a concave spherical base except for the central part when the hole for the hanging tool is divided into three equal parts in the axial direction. 5 mm or more from any of the above, since it is provided alone and penetrating perpendicular to the axis, high stress is not applied to the portion where the hole for the hanging tool is provided,
The weight is reduced by the amount of the hole for the hanging tool. Further, in the manufacturing method of the present invention, a push rod shape having spherical bases at both ends is formed in near net shape, a hole for a hanging tool is formed in at least one end side, and the hanging tool is fitted into the hole for the hanging tool. After inserting, hanging and baking, after firing, it is only necessary to grind the spherical base at both ends, so that ceramic material can be saved, and compared to the conventional method, the hooked part can be cut or the concave spherical base is polished. The step of performing rough processing is omitted, and a practically excellent effect is exhibited, for example, the processing time can be significantly reduced and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory view of one shape of a ceramic push rod according to an embodiment of the present invention.

FIG. 2 is an explanatory view of a ceramic push rod in which a position of a hole for a hanging tool in FIG. 1 is changed.

FIG. 3 is an explanatory view of a state of firing a ceramic push rod.

FIG. 4 is an explanatory view of a state of firing a conventional ceramic push rod.

FIG. 5 is an explanatory view showing a state in which a hook portion of a conventional ceramic push rod is cut.

FIG. 6 is an explanatory view showing a state in which a concave spherical base is roughly machined after firing in a conventional ceramic push rod.

FIG. 7 is an explanatory diagram of a state of firing a conventional ceramic push rod.

FIG. 8 is an explanatory diagram of a firing state of a ceramic push rod having a protruding stepped portion.

FIG. 9 is an explanatory diagram of a firing state of a ceramic push rod having a groove-shaped stepped portion.

[Explanation of symbols]

1. Ceramic push rod, 1a .. concave spherical base, 1b .. convex spherical base, 2 .. hole for hanging tool, 3 .. ceramic bar, 4 ..

Claims (2)

(57) [Claims] 1. When divided into three equal parts in the axial direction, a portion excluding the central portion is 5 m from both the concave spherical base and the convex spherical base.
A ceramic push rod in which a hole for a hanging tool is provided independently at a distance of m or more and perpendicularly to the axis. 2. A push rod shape having spherical bases at both ends is cast into a ceramic material to form a near-net shape, and at least one end side of the near-net-shaped push rod is provided with a hole for a hanging member. 2. The push rod is hung by inserting a hanger into the hanger hole, and after firing, the spherical bases at both ends are polished.
A method for manufacturing the ceramic push rod described in the above.