JPH05123740A - Ceramics roll device - Google Patents

Abstract

(57) [Abstract] [Purpose] The object of the present invention is to effectively prevent the roll body from being damaged by an impact force acting on the roll body,
An object of the present invention is to provide a ceramic roll device capable of increasing the durability of the device and facilitating maintenance management. In the ceramic roll device according to the present invention, a convex engagement portion 2a formed on a metal shaft 1a and a concave engagement portion 4a formed on a ceramic roll 3a are fitted together.
In a ceramic roll device configured to rotate a ceramic roll 3a integrally with a metal shaft 1a, a contact surface S between the convex engagement portion 2a and the concave engagement portion 4a.
The buffer material 7a is interposed at least in the stress concentration portion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll device made of ceramics, and more particularly, to effectively prevent the roll body from being damaged by an impact force acting on the roll body, thereby increasing the durability of the device and maintaining and managing it. The present invention relates to a ceramic roll device capable of facilitating the operation.

[0002]

2. Description of the Related Art In a roll forming process, a drawing process, a sizing straightening process and the like in a seamless steel pipe manufacturing process and a welded pipe manufacturing process, various types of roll devices are provided according to the purpose of processing the material. For example, in the high-frequency welded pipe manufacturing process, a roll device in which a plurality of forming rolls made of cemented carbide is arranged in multiple stages and a high-frequency welder for welding the seam of the roll-formed cylindrical open pipe are arranged. , The strips that have been put in as raw materials are sequentially inserted into a plurality of roll devices to be pressurized and gradually formed into a cylindrical open pipe, and further, due to the Joule heat generated by the welding current of the high frequency welder. The butt portions are integrally joined to form a welded pipe.

However, in the conventional roll device, the leakage current from the high-frequency welder leaks to the outside through the bearing through the conductive cemented carbide forming roll, so that the current consumption during operation is reduced. However, there is a problem that the bearing is apt to be damaged due to the electrolytic corrosion action as the height becomes higher.

Furthermore, since a large impact force acts on the forming roll, cracking and deformation are likely to occur, and the roll surface is easily scratched, which is a major cause of deteriorating the surface properties of the roll-formed product. ..

On the other hand, since cooling water is constantly sprayed to prevent the temperature rise of the forming roll, there is a drawback that the thermal shock acting on the forming roll becomes large and the forming roll is damaged early. ..

As a measure for solving the above-mentioned problems, for example, as disclosed in Japanese Patent Application No. 2-180470 filed by the applicant of the present application, a ceramic roll device in which the molding roll itself is made of a ceramic material is also used. Proposed. As shown in FIGS. 6 and 7, this ceramic roll device is formed by a convex engaging portion 2 formed integrally with a metal shaft (rotary shaft) 1 and a ceramic roll 3 made of, for example, silicon nitride. Fit the concave engagement part 4,
The ceramic roll 3 is configured to rotate integrally with the metal shaft 1.

According to the above-mentioned ceramic roll device,
Since the forming roll is made of a ceramic material having excellent electric insulation and thermal shock characteristics, the open pipe 5 as the material to be processed and the metal shaft body 1 are electrically insulated from each other, and the electric power of the bearing due to the leakage current is reduced. It has become possible to eliminate corrosion and effectively prevent crack damage due to quenching by cooling water.

[0008]

However, in the above-mentioned conventional ceramics roll device, the concave engagement portion 4 formed in the main body of the ceramics roll 3 and the metal shaft 1 are provided.
A minute clearance d is formed between the convex engagement portion 2 and the convex engagement portion 2 which are integrally formed with each other. The clearance d is inevitably formed due to the fitting tolerance with the concave and convex engaging portions 4 and 2 and the processing accuracy of the ceramic roll.

Due to the presence of the clearance d, the concave engaging portion 4 and the convex engaging portion 2 are used, for example, when the metal shaft 1 is rotated for start-up or when the load applied to the roll changes abruptly. Since and are not in surface contact but in line contact or point contact, stress concentrates on the contact part in addition to stress concentration in structural mechanics. In the example shown in FIG. 7, stress concentration is likely to occur at the four corners of the concave engagement portion 4, cracks 6 occur from these corners, and the ceramic roll 3 is damaged in a short-term operation. There was a point. A large amount of labor and time are required for maintenance and management work such as replacement of the ceramic roll 3, and the production efficiency of products such as welded pipes is significantly reduced due to frequent stoppage of the production machine. There was a point.

As a countermeasure for the above, a large number of engaging grooves are provided in the axial direction on the outer surface of the metal shaft to form the shaft body in the shape of a spline shaft, while a ceramic-made roll is provided with a concave engaging portion that fits into the engaging groove. By forming it, a structure in which the contact area between the engaging groove and the concave engaging portion is increased and stress concentration is prevented has been considered. However, the shape of the concave engaging portion is complicated, and it is extremely difficult to process a high hardness ceramic roll with high precision, and practical application is difficult.

The present invention has been made to solve the above problems, and effectively prevents the roll body from being damaged by the impact force acting on the roll body, thereby increasing the durability of the apparatus. It is an object of the present invention to provide a ceramic roll device that can facilitate maintenance management.

[0012]

In order to achieve the above object, the present invention provides a ceramic roll by fitting a convex engagement portion formed on a metal shaft and a concave engagement portion formed on a ceramic roll. In a ceramics roll device configured to rotate integrally with the metal shaft, a cushioning material may be provided at least in the stress concentration portion of the contact surface between the convex engagement portion and the concave engagement portion. Characterize.

From the viewpoints of strength characteristics and price, silicon nitride (Si ₃ N ₄ ), aluminum oxide (Al
₂ O ₃ ), zirconium oxide (ZrO ₂ ), silicon carbide (SiC) and the like are preferable.

In particular, the bending strengths of sintered bodies made of silicon nitride (Si ₃ N ₄ ) and zirconium oxide (zirconia: ZrO ₂ ) are very large at about 70 and 125 kg / cm ² , respectively, and also have fracture toughness values. since high as 7~9MPa · m ^-3/2, is particularly suitable as a molding roll material for manufacturing the wall thickness is large welded tubes.

On the other hand, alumina (Al ₂ O ₃ ) has a bending strength of about ²⁰ to 27 kg / cm ² , but it is not sufficient as a strength characteristic of a forming roll for producing a thin welded pipe having a wall thickness of about 1 to 3 mm. is there. From the viewpoint of thermal shock resistance, silicon nitride and silicon carbide are preferable. Also, as the cushioning material,
The hardness is lower than that of a metal shaft, and even if an impact force exceeding the elastic limit is applied, it is stretched without being broken, and is plastically deformed to absorb the impact force. It is recommended to use metal. As a specific example of the ductile metal, copper, aluminum, silver, or the like is adopted, and the ductile metal is provided on the contact surface of the concave-convex engaging portion in the state of a metal piece or a metal foil. These cushioning materials are integrally fixed in advance to a concave engaging portion formed on the roll body.

Further, by forming the contact surface by inclining it so that the inclination angle formed by the contact surface and the metal shaft is 0 to 10 degrees, the contact form in the concave-convex engaging portion becomes a surface contact ratio. Since it is increased, it is possible to disperse the concentrated stress as compared with the conventional structure in which point contact or line contact is made, and it is possible to significantly improve the impact resistance of the roll. When the inclination angle exceeds 10 degrees, the component of force in the axial direction with respect to the rotational force to be originally transmitted in the circumferential direction of the rotating shaft becomes large, so that the transmission efficiency of the rotational force decreases. Therefore, the inclination angle is preferably set to 10 degrees or less, and more preferably set to 2 to 8 degrees.

Here, the ceramic roll is manufactured in accordance with the following general ceramic sintered body manufacturing method.

That is, Si ₃ having an average particle size of 1 to 70 μm
₂ to 6 wt% of a sintering aid such as Y ₂ O _{3 is} added to a ceramic powder such as N ₄ , ZrO ₂ , Al ₂ O ₃ and SiC, and the mixture is uniformly mixed in a ball mill. It is filled in a mold and press-molded to prepare a roll-molded body. Next, after forming a through hole for inserting a metal shaft body and a groove for inserting a cushioning material in the center of the roll molded body,
Insert the roll compact into a firing furnace and set the temperature to 1600-185.
A ceramic roll having a predetermined surface roughness and dimensions is prepared by sintering at 0 ° C. and subjecting the sintered body after cooling to mechanical grinding and polishing.

[0019]

According to the ceramic roll device having the above structure, the cushioning material is provided on the contact surface between the convex engaging portion and the concave engaging portion, so that the clearance is hardly formed. In addition, the impact force that acts between the metal shaft and the ceramic roll is absorbed by the cushioning material, effectively preventing the ceramic roll from being damaged, greatly improving the durability of the roll device, and maintaining it. Management is also extremely easy.

Further, since the inclination angle formed by the contact surface and the axis of the metal shaft is set to about 0 to 10 degrees and the contact surface is inclined, the concave-convex engaging portion comes into contact with each other by surface contact. , It becomes possible to disperse concentrated stress,
The impact resistance of the roll can be greatly improved.

[0021]

An embodiment of the present invention will be described with reference to the accompanying drawings. 1 is a partial cross-sectional view of a main part showing a first embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG. In addition, the same elements as those of the conventional example shown in FIGS.

That is, in the ceramic roll device according to this embodiment, the convex engagement portion 2a formed on the metal shaft 1a and the concave engagement portion 4a formed on the Si ₃ N ₄ roll 3a are fitted to each other, In a ceramic roll device configured to rotate a Si ₃ N ₄ roll 3a integrally with a metal shaft 1a, a corner portion P of each contact surface between the convex engagement portion 2a and the concave engagement portion 4a. _{1 to} P ₄ is provided with a copper cushioning material 7a interposed.

In the apparatus of this embodiment, as shown in FIG. 2, an example of the configuration of an apparatus in which the metal shaft 1a is activated and rotated only clockwise is shown. In this case, stress concentration is likely to occur at the corners P _{1 to} P ₄ of the contact portions of the concave and convex engaging portions 4 a and 2 a formed in a square cross section. Therefore, a groove having a half-moon shape in cross section is formed in advance at a position corresponding to the concave engaging portion 4a of the Si ₃ N ₄ roll 3a, and a copper cushioning material 7a fitted into the groove is embedded.

According to the above-mentioned embodiment, the corner portions P _{1 to} P ₄ where stress concentration is particularly likely to occur in the contact surface with the concave-convex engaging portion,
Since the cushioning material 7a made of ductile metal is interposed, the impact force acting between the metal shaft body 1a and the Si ₃ N ₄ roll 3a is absorbed by the ductility of the cushioning material 7a. .. Therefore, breakage of the Si ₃ N ₄ roll 3a was effectively prevented, and the durability and maintenance of the roll device could be greatly improved. By the way, as compared with the roll device of the conventional structure shown in FIGS. 6 to 7, the continuous usable time was 6.7 times as long as an average.

Next, a second embodiment of the present invention will be described with reference to FIG. In the ceramic roll device shown in FIG. 3, the concave-convex engaging portions 4b and 2b are formed by setting the sectional shape of the concave-convex engaging portions shown in the first embodiment to an oval shape, and the concave-convex engaging portions 4b face each other. It is manufactured under the same conditions as in the first embodiment except that copper cushioning material 7b having a half-moon shaped cross section is provided at each end of each pair of contact surfaces.

According to the roll device of the second embodiment described above, even if the metal shaft 1b is rotated to the left or right in the drawing, the corners of the convex engaging portion 4b are concavely engaged via the cushioning material 7b. It has a structure that abuts on the joint portion 2b. Therefore, the shock absorbing action of the cushioning material 7b is exerted regardless of the rotation direction, so that the durability of the Si ₃ N ₄ roll 3b can be further enhanced.

Next, a third embodiment of the present invention will be described with reference to FIGS. The ceramic roll device shown in FIG. 4 sets the inclination angle θ between the contact surface S for transmitting the rotational force of the metal shaft 1c to the ceramic roll 3c and the axis C of the metal shaft 1c to 6 degrees. The contact surface S is provided with a copper foil cushioning material 7c having a thickness of 0.5 mm. On the end surface of the ceramic roll 3c opposite to the contact surface S, a fixing metal fitting 8 for restraining the axial movement of the ceramic roll 3c is attached.

The rotating force of the metal shaft 1c is
From the convex engaging portion 2c through the ceramic roll 3c
It is transmitted to the concave engaging portion 4c of c. At this time, since the contact surfaces S of the concave-convex engaging portions 4c and 2c are formed to be inclined, the ratio of the concave-convex engaging portions 4c and 2c that are in surface contact with each other is large. Since stress concentration due to point contact or line contact is less likely to occur, damage to the ceramic roll 3c can be more effectively prevented.

Further, in this embodiment, since the contact surface S is formed to be inclined, when the concave and convex engaging portions 4c and 2c are fitted to each other to transmit the rotational force, the ceramic roll 3c is rotated. A component force that pushes in the direction is generated. However, the movement of the ceramic roll 3c due to this component force causes the fixing metal fitting 8 to move.
Is prevented by.

[0030]

As described above, according to the ceramics roll device of the present invention, the cushioning material is provided on the contact surface between the convex engaging portion and the concave engaging portion so that no clearance is formed. In addition, the impact force that acts between the metal shaft and the ceramic roll is absorbed by the cushioning material, effectively preventing the ceramic roll from being damaged, greatly improving the durability of the roll device, and maintaining it. Management is also extremely easy.

Further, by setting the inclination angle formed by the contact surface and the axis of the metal shaft body to about 0 to 10 degrees and inclining the contact surface, the concave-convex engaging portion comes into contact with each other by surface contact. , It becomes possible to disperse concentrated stress,
The impact resistance of the roll can be greatly improved.

[Brief description of drawings]

FIG. 1 is a first ceramic roll device according to the present invention.
FIG. 3 is a partial cross-sectional view of a main part showing an embodiment.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a side sectional view of an essential part of a second embodiment of the present invention.

FIG. 4 is a partial sectional view of an essential part showing a third embodiment of the roll device according to the present invention.

5 is a sectional view taken along the line VV in FIG.

FIG. 6 is a partial cross-sectional view showing a main part of a conventional ceramics roll device.

7 is a sectional view taken along the line VII-VII in FIG.

[Explanation of symbols]

1,1a, 1b, 1c Metal shaft 2,2a, 2b, 2c Convex engagement part 3,3a, 3b, 3c Ceramic roll 4,4a, 4b, 4c Recessed engagement part 5 Open pipe (workpiece ) 6 cracks 7a, 7b, 7c cushioning material 8 fixing brackets d clearance P ₁ to P ₄ corners S contact surface C axis θ angle of inclination

Claims (4)

[Claims] 1. A convex engaging portion formed on a metal shaft and a concave engaging portion formed on a ceramic roll are fitted together,
In a ceramic roll device configured to rotate a ceramic roll integrally with a metal shaft body, a cushioning material is interposed in at least a stress concentration portion of a contact surface between the convex engagement portion and the concave engagement portion. A ceramic roll device characterized by the above. 2. The ceramic roll device according to claim 1, wherein the cushioning material is a ductile metal. 3. The tilt angle formed by the contact surface for transmitting the rotational force of the metal shaft to the ceramic roll and the axis of the metal shaft is set to 0 to 10 degrees.
The ceramic roll device described. 4. The ceramic roll device according to claim 1, wherein the ceramic is made of at least one of silicon nitride, aluminum oxide, zirconium oxide, and silicon carbide.