JP2578531B2 - Manufacturing method of precision hollow ceramic body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a precision ceramic body, and more particularly, to a method for manufacturing a precision hollow ceramic body capable of manufacturing a precision ceramic product by as-fire.

[0002]

2. Description of the Related Art Since ceramic products require a firing step, precision products and parts are rarely produced by as-fire, and parts requiring precision must be ground. General. For example,
Accuracy is required for the turbine blade, but since there is no connection with other parts, even if the accuracy is somewhat low, there is not much problem. Specifically, the ceramic turbine rotor has a total length of 40 mm and a length from the support to the tip of about 20 m.
m has an accuracy of 0.4 mm. Further, since the part requiring accuracy is a solid part, the firing deformation is not so large.

[0003] For the reasons described above, there has been no established technique for producing a ceramic product by as-fire, and there has been no request for it. Conventionally, a technique has been adopted in which a deviation of a predetermined position of a ceramic molded body is measured for each of the X, Y, and Z axes, and this is fed back and divided.
That is, this is a method of measuring the displacement of the position by the change of the point.

[0004] In recent years, environmental pollution due to automobile exhaust gas has become a serious social problem. One method of solving this problem is to line the inner surface of an engine exhaust port with a ceramic port liner. It has been proposed to increase the temperature of the exhaust gas by adiabatic action. As described above, this ceramic port liner is a part of the ventilation pipe of an automobile. If the precision is poor, the flow of exhaust gas is disturbed at a connection portion with other parts, and the energy loss of exhaust gas is increased. There is. Furthermore, as a process of assembling and manufacturing the engine, there is a process of fitting a ceramic component to a mold and heating the whole.
At this time, if the ceramic port liner does not accurately contact the mold and a gap is generated, heat transfer is deteriorated and a problem that the ceramic port liner does not fit into the mold occurs.

[0005]

Therefore, when a port liner made of ceramic was manufactured by as-fire by a conventional method, the conventional method only measures the positional deviation by a change in point as described above. Therefore, it is difficult to feed back the three-dimensional firing deformation without considering the deformation in the middle part. Therefore, even if the number of times of the feedback is increased, there is a limit in improving the three-dimensional accuracy.

[0006]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method of manufacturing a precision hollow ceramic body which can manufacture a precision ceramic product by as-fire. And according to the present invention,
In producing a hollow ceramic body having a three-dimensional free-form surface on its surface , one or more reference lines are formed on the curved surface of the hollow ceramic molded body at its ridges, valleys, outlines, and / or cross-sections. After firing the formed body, the deformation amount of the reference line in the formed body in the fired body is measured, and the deformation amount of the reference line is fed back to the design of the forming die, and the firing deformation amount is taken into consideration. It can be achieved by a method of manufacturing a precision hollow ceramic body, which is divided.

[0007]

According to the present invention, several reference lines are set for a large deformation portion of the ceramic body, and the amounts of deformation of these reference lines in the fired body are measured and fed back. As a result, it is possible to produce a precise ceramic body by as-fire even with a hollow ceramic body having a three-dimensional free-form surface.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. FIG. 1 is a perspective view showing an example of a ceramic port liner. The port liner 1 has two valve holes 2 on the cylinder side, one exhaust port 3 on the exhaust manifold side, and has a three-dimensional free-form surface on the surface. It is a hollow ceramic body of complicated shape.

First, as shown in FIGS. 1 to 3, ridge lines A and B, valley line C, outer peripheries D, E and F of the end face, and outlines G and H are used as reference lines for this port liner 1. , Measure its dimensions. Next, CAD (Computer Ai
ded Design) Design and create a mold for port liner 1 using the system. Next, using the obtained mold, a port liner molded body is molded, dried and fired,
A port liner fired body is manufactured.

With respect to the port liner fired body obtained here, the aforementioned ridge lines A, B, valley line C, and outer peripheries D, E, F of the port liner molded body are measured using a three-dimensional measuring device, a projector, and a caliper. , And the reference lines such as the outlines G and H, the dimensions and the positional relationship in the obtained fired body are three-dimensionally measured, and the respective deformation amounts are three-dimensionally examined. By feeding back the obtained deformation amount to the design of the molding die in the CAD system, even a hollow ceramic body having a complicated shape having a three-dimensional free-form surface on the surface of a port liner or the like can be precisely formed by as-fire. A hollow ceramic body can be manufactured and manufactured.

The accuracy of the as-fired ceramic port liner manufactured according to the present invention is 100% in total length.
With a thickness of 3 mm to about 0.35 mm, a thickness of about 0.35 mm could be achieved. Examples of the hollow ceramic body having a three-dimensional free-form surface on the surface to which the present invention can be preferably applied include an exhaust manifold, an elbow portion of a pipe, and the like in addition to the ceramic port liner.

[0012]

As described above, according to the present invention,
Since the three-dimensional firing deformation is taken into consideration, a precise fired ceramic body can be manufactured by as-fire for a hollow ceramic body having a complicated shape having a three-dimensional free-form surface on the surface.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a ceramic port liner.

FIG. 2 is an explanatory diagram showing an example of a reference line of a port liner.

FIG. 3 is an explanatory diagram illustrating an example of a reference line of a port liner.

[Explanation of symbols]

 1 Port liner 2 Valve hole 3 Exhaust port

Claims (1)

(57) [Claims] In producing a hollow ceramic body having a three-dimensional free-form surface on its surface, a curved shape of a hollow ceramic molded body is used.
Taking one or more reference lines in the ridge line, valley line, outer shape line and / or cross section on the surface , and after firing the hollow ceramic molded body, measure the deformation amount of the reference line in the fired body in the molded body, Designing the mold for the amount of deformation of the reference line
A method for producing a precision hollow ceramic body, characterized in that the method comprises: