JP3310683B2 - Cylinder manufacturing method - 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 cylinder used for kneading plastic materials and food materials.

[0002]

2. Description of the Related Art In kneading plastic or food materials, a screw or rotor is rotatably mounted in a cylinder, a plurality of materials are charged into the cylinder, and the screw or rotor is rotated by rotation of the screw or rotor. Kneading and transfer are performed. At this time, the inner diameter surface of the cylinder is subjected to friction due to the flow of the material and corrosion due to a substance generated by thermal decomposition of various organic substances added together with the material. Therefore, a corrosion-resistant and wear-resistant alloy powder is adhered to the inner surface of the cylinder as a surface guard.
Japanese Unexamined Patent Publication No. 2 (Kokai) No. 2 is disclosed as an example. In this method, a through hole is formed in the axial direction of the cylinder, a core is inserted into the through hole of the cylinder, and a metal for the inner surface guard is provided in a space between the outer surface of the core and the inner surface of the cylinder through hole. This is a method in which a powder is filled and is integrally attached to the inner surface of the cylinder through-hole via hot isostatic pressing means (hereinafter referred to as HIP processing means).

[0003]

In the conventional method of manufacturing a cylinder, when the inner diameter of the center of the cylinder is equal to or smaller than the inner diameter of both ends, the core can be easily removed. However, in the case where the inner diameter at the center of the cylinder is larger than the inner diameter at both ends as shown in FIGS. 4, 5, and 6, which is used to improve the kneading performance, as in the conventional method described above. Cannot escape the core. That is, in the case of an extruder having a cylinder 1 and a screw 2 whose cross section perpendicular to the axis has a polygonal or similar shape, which is proposed as an example of a method for improving the kneading performance, the extruder before and after the cylinder 1 There is a cylinder 3 having a circular cross section, and the screw 4 of the cylinder 3 is formed in a circular cross section. The cylinder 1 has a polygonal cross section and the cylinder 3 has a circular cross section.
In the transition portion 5, the inner diameter is formed from a large diameter to a small diameter. Therefore, when the core is used as described above, as shown in FIG. 7, the cylinder 6 is formed by providing the ring 6 so as to be able to be fitted therein, and each is manufactured by HIP processing means and then fitted. . In addition, 8 shows a HIP lining layer. This requires a great deal of labor for processing,
In order to prevent leakage from the joint surface of the ring 6, it was necessary to further perform lapping or the like. The present invention has been proposed to solve the above-mentioned conventional problems.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a metal core having a larger thermal expansion coefficient than a cylinder material in a through-hole communicating with the cylinder in the axial direction. Is inserted into the space between the outer peripheral surface of the core and the inner surface of the cylinder through-hole with metal powder for guarding the inner surface and integrally formed on the inner surface of the cylinder through-hole via hot isostatic pressing means. In this method, the inner diameter of the center portion of the cylinder is formed to be larger than the inner diameters of both ends by electric discharge machining by inserting an electrode into the through-hole, and this is used as a means for solving the problem.

[0005]

Method for producing a cylinder of the effects of the present invention, pre-cylinder
A through-hole communicating in the axial direction is drilled, and a core is inserted into the through-hole for applying an alloy for improving the wear resistance and corrosion resistance of the inner surface of the cylinder. Keep it. Same child
Inner surface girder in the space between the outer peripheral surface of
Metal powder for hot metal, and seal it through hot isostatic pressing means.
It is integrally attached on the inner surface of the through hole. Then, insert the electrode into the through hole and move the electrode appropriately.
Therefore, the inner diameter of the center of the cylinder is
It is formed larger than the diameter . Even if the cylinder has a large diameter at the center and a small diameter at both ends, the electrode can be pulled out of the through hole formed to be removable.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an embodiment of the present invention; FIG. First, FIG. 1 shows a first embodiment of the present invention, and is a cross-sectional view showing a working method for obtaining the same cylinder as the conventional one shown in FIG. That is, a through hole 11 communicating with the cylinder 10 in the axial direction is formed by a drill or the like. Next, an electrode 12 having an inner peripheral cross-sectional shape (cylinder corresponding to FIG. 7) of the finished cylinder is inserted into the through hole 11, and electric discharge machining is performed. The cross-sectional shape perpendicular to the axis in FIG. 1 is hexagonal, and the inner diameter at both ends is formed smaller than the inner diameter at the center. Therefore, as shown in the figure, the electrode shape 12a at the center is a hexagonal prism and both ends 12b are It has a hexagonal pyramid shape. By performing electric discharge machining (for example, NC electric discharge machining) using the electrode 12 having such a shape, the cylinder 10
Has the same shape as the electrode 12. In the electric discharge machining, as in the prior art, spark discharge is repeatedly performed in an insulating liquid such as white kerosene to gradually remove the inner peripheral portion of the cylinder. By performing such an operation, the cylinder cross-sectional shape is finished to the electrode cross-sectional shape, and the electrode can be removed after the completion even if the diameter of the central portion of the cylinder is larger than the diameter of both ends.

FIGS. 2 and 3 show a second embodiment of the present invention, which is a manufacturing method for improving the wear resistance and corrosion resistance of a cylinder. FIG. 2 is a cross-sectional view showing a state in which HIP processing is performed. Figure,
FIG. 3 is a sectional view showing a state in which electric discharge machining is performed. In the figure, a cylinder 100 has a through hole 110 formed in the axial direction by a drill or the like, and a metal core 15 having a larger thermal expansion coefficient than the material of the cylinder 100 is inserted into the through hole 110, and the outer periphery of the core 15 is formed. Surface and through hole 11 of cylinder 100
The space between the inner surface and the inner surface of the inner surface is filled with metal powder for inner surface guard, and HIP (hot isostatic pressing means) is performed. Then, by cooling the cylinder, the core can be detached from the cylinder due to the difference in thermal expansion of the core, and the metal powder is integrally deposited on the inner surface of the cylinder through-hole, and the HIP lining layer 1
6 are formed. By attaching the metal to the inner peripheral surface of the cylinder in this manner, the wear resistance and the corrosion resistance can be improved. Next, the electrode 12 of the through hole 110 of the cylinder to which the HIP lining layer 16 is attached is inserted to perform electric discharge machining. The procedure of the electric discharge machining is the same as that described above, and the description is omitted. The cylinder obtained in this way can improve abrasion resistance and corrosion resistance, and should be manufactured even if the inner diameter at the center of the cylinder is larger than the inner diameter at both ends. Can be.

[0008]

According to the method of manufacturing a cylinder of the present invention, an electrode is inserted into an axial through hole formed in the cylinder to perform electrical discharge machining to manufacture the cylinder. Even in the case of a cylinder shape having a larger diameter than the inner diameter of the portion, there is no need to insert a separate ring as in the conventional case, and it can be manufactured integrally. In addition, it can be manufactured more easily than in the past, and leakage from the joint can be prevented. More cylinder penetration
The metal powder applied to the inner diameter
Abrasion and corrosion resistance can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a method for manufacturing a cylinder according to a first embodiment of the present invention.

FIG. 2 is a sectional view illustrating a method for manufacturing a cylinder according to a second embodiment of the present invention.

FIG. 3 is a sectional view illustrating a manufacturing state of the second embodiment following FIG. 2;

FIG. 4 is a sectional view of a conventional cylinder and screw.

FIG. 5 is a sectional view taken along line A-A of FIG. 4;

FIG. 6 is a sectional view taken along the line BB of FIG. 2;

FIG. 7 is a sectional view showing an example of a conventional cylinder manufacturing method.

[Explanation of symbols]

 10,100 cylinder 11,110 through hole 12 electrode 15 core 16 HIP lining layer

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields investigated (Int. Cl. ⁷ , DB name) B29B 7/58 B29C 47/00-47/96 B22F 3/14 B22F 5/00 B23H 1/00

Claims (1)

(57) [Claims] A through-hole communicating with the cylinder in the axial direction is formed, and a metal core having a higher thermal expansion coefficient than a material constituting the cylinder is inserted into the through-hole of the cylinder. A metal powder for inner surface guard is filled in a space between the inner surface of the cylinder and the inner surface of the cylinder through-hole, and the metal powder is integrally adhered to the inner surface of the cylinder through-hole via hot isostatic pressing means. A method for manufacturing a cylinder, wherein the inner diameter of a central portion of the cylinder is formed to be larger than the inner diameters of both ends by insertion and electric discharge machining.