JP5828388B2 - Bearing equipment for molten metal plating bath - Google Patents

Description

  The present invention is a molten metal plating apparatus for plating molten zinc, molten aluminum or other molten metal on the surface of a steel sheet, and is immersed in a molten metal plating bath to rotatably support a support roll or a sink roll as a rotating body. The invention relates to a bearing device for a metal plating bath.

  FIG. 6 shows a schematic configuration diagram of a molten metal plating apparatus in which a bearing apparatus for a molten metal plating bath related to the above technical field (hereinafter sometimes simply referred to as a bearing apparatus) is incorporated. As shown in FIG. 6, a molten metal plating apparatus 90 is immersed in a plating tank 92 in which a molten metal plating bath (hereinafter sometimes simply referred to as “plating bath”) 91 is stored, and a surface layer portion of the plating bath 91. And a snout 93 for preventing oxidation of the steel sheet W introduced into the plating bath 91, a sink roll 98 disposed in the plating bath 91, and the upper portion of the sink roll 98 in the plating bath 91. And a gas wiping nozzle 96 positioned slightly above the surface of the plating bath 91. An external driving force is not applied to the sink roll 98 itself, and the sink roll 98 is driven counterclockwise by a frictional force caused by contact with the traveling steel plate W. The support roll 97 is typically a drive roll connected to an external motor (not shown). The support roll 97 may be a non-driving type in which no external driving force is applied. A sink roll 98 and a pair of support rolls 97, which are rolls for a molten metal plating bath, are rotatably supported by bearing devices 1 and 1 attached to frames 94 and 95, respectively, and are always integrated into the plating bath 91 as a unit. Soaked.

  The steel plate W enters the plating bath 91 from the oblique direction through the snout 93, and the traveling direction can be changed upward via the sink roll 98. The steel plate W rising in the plating bath 91 is sandwiched between a pair of support rolls 97 that press the steel plate W with a constant force, so that the pass line is maintained and warpage and vibration are prevented. The gas wiping nozzle 96 sprays high-speed gas onto the steel sheet W coming out of the plating bath 91, and uniformly adjusts the thickness of the molten metal plating attached to the steel sheet W by the gas pressure of the high-speed gas. In this way, a steel plate W on which molten metal plating has been applied can be obtained.

  Here, in the bearing device 1, each shaft portion of the support roll 97 and the sink roll 98, which are rotating bodies immersed in a molten metal plating bath (hereinafter sometimes simply referred to as a plating bath) 91, is a bearing device. However, there has been a demand for the development of a bearing device 1 that has high wear resistance against a highly corrosive plating bath and high wear resistance against sliding with a rotating shaft portion.

  In order to solve such a problem, a bearing device has been conventionally proposed, and an example thereof is disclosed in Patent Document 1 below. Patent Document 1 states that “in the support roll in the molten metal bath in the molten metal plating line, the support roll is undriven, and self-fluxing alloy spraying is performed on the outer periphery of the sleeve that is in sliding contact with the support roll bearing. `` A support roll in a non-driven molten metal bath characterized in that a bush whose cross-sectional shape is mirror-finished on the surface is provided and the outer periphery of the bush is a spherical bearing '' is disclosed and functions as a bearing The bush and the arm as a storage member that holds the bush function as a bearing device.

JP 2005-248298 A

  The bearing device disclosed in Patent Document 1 is provided with a self-fluxing alloy layer on the outer peripheral portion of the sleeve that slides with the inner peripheral surface of the bush, thereby providing corrosion resistance to the plating bath and wear resistance to sliding of the shaft portion. However, when the bush (bearing) is made of ceramics and the arm (housing member) is made of metal, there are the following problems. That is, in the bearing device of Patent Document 1, the bush is held in a hollow portion formed in the arm. Then, when the shaft portion and the sleeve of the support roll are fitted into the through hole of the bush held in the hollow portion of the arm, the arm, the bush and the shaft portion are in close contact with each other through a slight gap, The hollow portion is almost sealed. Here, when the above-mentioned bearing device is immersed in the plating bath, the arm, the bush and the shaft portion are thermally expanded, and the plating bath soaked from the expanded gap between the sleeve and the bush and the gap between the bush and the arm is Enter the hollow part of the arm. When performing maintenance or the like, the support roll and the bearing device are pulled up from the plating bath, but the plating bath hardly flows out from the hollow portion of the sealed case when pulled up, and the plating bath remains in the hollow portion. There is a case. When the bearing device is cooled after being pulled up, the plating bath remaining in the hollow portion is solidified, and the metal case having a large thermal expansion coefficient contracts more than the ceramic bush. For this reason, the solidified plating bath may be pressed against the bearing in a shrinking case, and the pressing force may damage the bearing.

  The present invention has been made by the inventor's earnest examination of the problems of the prior art described above, and has an insertion portion into which a shaft portion of a rotating body such as a sink roll immersed in a plating bath is inserted from one end. A ceramic bearing and a metal housing member having a member arranged so as to block one opening and having a hollow portion in which the bearing is housed through the other opening, the shaft portion being rotatable An object of the present invention is to provide a bearing device that is supported and capable of smoothly flowing out a plating bath that has entered the inside of the bearing device when immersed in the plating bath when the shaft device is pulled up. .

  One aspect of the present invention that achieves the above object is a bearing device for a molten metal plating bath that rotatably supports a shaft portion of a rotating body immersed in a molten metal plating bath, wherein the shaft portion is inserted from one end. A ceramic bearing having an insertion portion, and a metal housing member having a member arranged to block one opening and having a hollow portion in which the bearing is housed through the other opening. The member is a bearing device for a molten metal plating bath characterized by having a discharge port for a molten metal plating bath that opens to the bottom surface of the hollow portion.

  In addition, it is preferable that the bearing has a notch portion formed in a lower portion thereof, and the discharge port is formed at a position corresponding to the notch portion. In addition, it is desirable that the storage member has an opening formed in an upper part or a side part thereof.

  Furthermore, it is desirable that the bearing has an inclined surface formed in an upper portion thereof and inclined downward.

  In addition, it is preferable that the bearing has a bearing end portion disposed so as to close the other end of the insertion portion, and a flow hole for a molten metal plating bath is formed in the bearing end portion. Furthermore, it is desirable that the bearing of such an aspect has a hot water reservoir portion disposed so as to be interposed between the insertion portion and the bearing end portion.

  In addition, it is desirable that a gap be formed between the inner surface of the hollow portion and the outer peripheral surface of the bearing. The gap is preferably formed by a convex portion formed on the inner surface of the hollow portion or the outer peripheral surface of the bearing. Moreover, the said clearance gap may be formed of the recessed part formed in the inner surface of the said hollow part, or the outer peripheral surface of the said bearing.

  In addition, it is desirable that a coating having low wettability with the molten metal plating bath is formed on the outer peripheral surface of the bearing or the inner peripheral surface of the hollow portion of the housing member.

  According to the present invention, the object of the present invention can be achieved as described in detail below.

It is a perspective view of the bearing apparatus of one embodiment concerning the present invention. FIG. 2 is a front view, a rear view, a right side view, and a left side view of FIG. 1. FIG. 2 is a cross-sectional view taken along a vertical plane A and a horizontal plane H with respect to the shaft core of the bearing incorporated in the bearing device of FIG. 1. 4A is a cross-sectional view taken along the line CC in FIG. 3, and FIG. 4B is a view taken in the direction of arrow D in FIG. It is BB sectional drawing of FIG.2 (b). It is a schematic block diagram of the molten metal plating apparatus with which the bearing apparatus of FIG. 1 was integrated. It is a bottom view of the bearing apparatus concerning the 1st-3rd modification of the bearing apparatus of FIG. It is a front sectional view of a bearing device according to a fourth modification of the bearing device of FIG. It is a figure of the bearing apparatus concerning the 5th-7th modification of the bearing apparatus of FIG. It is a figure of the bearing apparatus concerning the 8th * 9th modification of the bearing apparatus of FIG. It is a sectional side view of the bearing apparatus concerning the 10th modification of the bearing apparatus of FIG. It is a sectional side view of the bearing apparatus concerning the 11th modification of the bearing apparatus of FIG.

  Hereinafter, a bearing device according to the present invention will be specifically described with reference to the drawings based on one embodiment and a plurality of modifications of the embodiment. Although the bearing device according to this embodiment and its modification is used by being incorporated in the molten metal plating apparatus described with reference to FIG. 6, the present invention is not limited thereto, As long as the effect is obtained, the present invention can be implemented with appropriate modifications within the range of identity. In addition, each component of the bearing device according to the present embodiment and the modifications thereof can be appropriately combined with each other as long as the effects of the present invention are exhibited. Further, in the following description, a bearing device that rotatably supports the shaft portion of the support roll as a rotating body immersed in the plating bath will be described as an example. However, the present invention may be applied to a sink roll or other molten metal plating bath. The same can be applied to the rotating body to be immersed.

  A bearing device according to an embodiment of the present invention will be described with reference to FIGS. 1 is a perspective view of the bearing device 1, FIG. 2 (a) is a right and left side view of the bearing device 1 of FIG. 1, FIG. 2 (b) is a front view thereof, and FIG. 3 is a cross-sectional view of the bearing device 1 taken along a plane A and a plane H that are perpendicular to the axis I of the bearing 8 incorporated in the bearing device 1 of FIG. 1, and FIG. FIG. 4B is a sectional view taken along the arrow D in FIG. 3, and FIG. 5 is a sectional view taken along the line BB in FIG. 2B. As shown in FIGS. 1 and 2 to 5, in the following description, the axis along the axis I of the bearing 8 is the X axis, the axis orthogonal to the X axis and horizontally intersecting the axis I is the Y axis, X An axis perpendicular to the axis I perpendicular to both the axis and the Y axis is referred to as a Z axis. As for the X-axis direction, the front side in FIG. 1 is referred to as the front, and the back side is referred to as the rear.

  As shown in FIGS. 1 and 2, the bearing device 1 of this aspect includes a ceramic bearing 8 having an insertion portion 8 a into which a shaft portion 97 a is inserted from one end, and a flat plate arranged so as to block one opening. And a metal housing member 2 having a hollow portion 2a in which the bearing 8 is housed from the other opening. The housing member 2 includes the hollow portion 2a. The plating bath discharge ports 4a to 7a open to the bottom surface 2b. According to the bearing device 1 having such a configuration, when the bearing device 1 is immersed in the plating bath together with the support roll, the plating bath enters between the storage member 2 and the bearing 8. Thereafter, when the bearing device 1 is pulled up from the plating bath for maintenance or the like, the plating bath that has entered between the storage member 2 and the bearing 8 opens to the bottom surface 2b of the hollow portion 2a provided in the storage member 2. It flows down through the discharge ports 4a to 7a and is discharged. Therefore, the plating bath remaining between the storage member 2 and the bearing 8 is suppressed, and damage to the bearing 8 due to the remaining plating bath can be suppressed. Hereinafter, the structure of the storage member 2 and the bearing 8 of this aspect will be described in detail. Here, although two sets of bearing devices 1 are arranged at both ends of the support roll, since the configuration of both is the same, only one bearing device 1 will be described, and description of the other bearing device 1 will be omitted. .

[Storage material]
As shown in FIG. 3, the storage member 2 of the present embodiment in which the cross-sectional shape along the X axis is a U-shaped bottomed cylindrical shape is joined in a rectangular frame shape so as to be orthogonal to each other as shown in FIG. 1. The cross-sectional shape perpendicular to the axis I, that is, the cross-sectional shape in the YZ plane, is formed by the four flat plate members 3 to 6 and the flat plate members 3 to 6 joined in the rectangular frame shape. It is formed by the flat plate member 7 joined to the rear end surfaces of the flat plate members 3 to 6 so as to block the opening at the rear end (one end) of the substantially rectangular hollow portion 2a. The bearing 8 is housed in the housing member 2 through the opening at the front end (the other end) of the hollow portion 2a. The bearing 8 housed in the hollow portion 2a is on the opposite side of the flat plate member 7 in the housing member 2. Movement in the X-axis direction is restricted by the fixing member 9 fixed to the end face.

  The entire inner surfaces 3c to 7c of the hollow portion 2a of the storage member 2 do not have to be flat, and the portions where the tops of the arc-shaped outer surfaces 8b to 8h of the bearing 8 come into contact with each other as long as described later. Furthermore, the inner surfaces 3c to 7c are not necessarily flat, and may be curved as long as the bearing 8 can be inserted. Further, since the flat plate member 7 is provided together with the fixing member 9 to restrict the movement of the bearing 8 in the X-axis direction, it is not necessary to completely close the hollow portion 2a of the storage member 2, as shown in FIG. As shown to c), the opening 7a may be formed in the flat member 7 so that a part of opening of the said hollow part 2a may be open | released.

  The metal flat members 3 to 7 constituting the storage member 2 are desirably made of a material having corrosion resistance against a plating bath having high chemical corrosion, and for example, stainless steel may be selected. Furthermore, in order to further improve the corrosion resistance, it is desirable to form a film such as a ceramic or cermet with low wettability with the plating bath on the surfaces of the flat members 3 to 7.

  Next, a plating bath outlet (hereinafter sometimes simply referred to as an outlet) provided in the storage member 2 will be described. As shown in FIG. 1 and FIG. 2, the discharge port of this aspect is hollow among the openings formed by cutting out the four corners so as to form a substantially ten-shaped shape for all of the five flat members 3 to 7. Four openings 5a formed in the lower flat plate member 5 that open to the bottom surface 2b of the portion 2a (also the inner surface 5c of the lower flat plate member 5), and the left, right, and rear flat plate shapes. Two openings 4a, 6a, and 7a formed in the lower portions of the members 4, 6, and 7 each serve as a discharge port that mainly discharges the plating bath. That is, the main discharge ports 4a to 7a are provided so as to open at the four corners of the bottom surface 2b in the hollow portion 2a of the storage member 2 having a rectangular cross section.

  Here, it is possible to discharge the plating bath from the bearing device 1 as a main discharge port by using only the four openings 5a of the flat plate member 5 without providing the flat members 4, 6, 7 with the openings 4a, 6a, 7a. However, in order to increase the cross-sectional area of the discharge port and discharge the plating bath more smoothly, the flat members 4, 6 and 7 are also provided with openings 4a, 6a and 7a which function as main discharge ports. It is desirable to keep it. The discharge port only needs to be provided in the hollow portion 2a of the storage member 2 so as to open to the bottom surface 2b, and the arrangement thereof is not particularly limited. In the case of the hollow portion 2 having a portion, it is desirable that openings 4a to 7a are provided at positions corresponding to the corner portions so that the plating bath does not remain at the corner portions, which are used as the discharge ports 4a to 7a. A modification of the storage member 2 relating to the arrangement of the discharge ports will be described later.

  Two openings 4d, 6d, and 7d formed on the upper portions of the left, right, and rear flat plate-like members 4, 6, and 7, respectively, are provided for the main discharge ports 4a to 7a, particularly for the bearing device 1 as a plating bath. It has a function as a secondary discharge port for smoothly flowing out the plating bath that has entered a large amount inside the bearing device 1 through the openings 4d, 6d, and 7d in the initial stage pulled up from. That is, only the main discharge ports 4a to 7a that open to the bottom surface 2b of the hollow portion 2a can discharge the plating bath that has entered the hollow portion 2a, but a large amount of plating bath remains in the hollow portion 2a. In the initial stage of lifting of the bearing device 1, there is a possibility that the discharge capacity of the plating bath may be insufficient only with the main discharge ports 4 a to 7 a, and the plating bath remaining during the pulling may solidify and damage the bearing 8. . On the other hand, in addition to the main discharge ports 4a to 7a, the plating bath is also discharged from the auxiliary discharge ports 4d, 6d, and 7d provided on the upper portions of the flat plate members 4, 6, and 7, so that plating is performed even in the initial stage of lifting. It becomes possible to discharge the bath from the hollow portion 2a more smoothly.

  Further, the openings 4d, 6d and 7d formed in the upper portions of the plate-like members 4, 6 and 7, the openings 3d formed in the four corners of the upper plate-like member 3, and the upper plate-like member communicating with the hollow portion 2a. According to the through-holes 4b and 6b which are openings formed in the central part of the left and right flat plate members 4 and 6 so as to communicate with the hollow part 2a and the through-hole 3b which is an opening formed in the central part of After pulling up 1 from the plating bath, outside air flows into the hollow portion 2a through these openings formed in the upper and side portions of the storage member 2. Thus, the plating bath remaining between the storage member 2 and the bearing 8 is easily discharged from the lower main discharge ports 4a to 7a without receiving any resistance. In addition, when an opening is not provided in a flat plate member other than the lower flat plate member 5 as in the following first to third modifications, for example, the through hole 3b is formed in the central portion of the upper flat plate member 3. It should be provided.

  From the viewpoint of smoothly discharging the plating bath from the hollow portion 2a, it is difficult for the plating bath to adhere to the inner surfaces 3c to 7c of the storage member 2 and the surfaces of the main discharge ports 4a to 7a and the sub discharge ports 4d, 6d, and 7d. It is desirable to form a film of ceramics, cermet or the like having low wettability with the plating bath. 1 and 2, reference numerals 4 b and 6 b correspond to the positions of the tops (see FIG. 4) of the surfaces 8 c and 8 e of the bearing 8 having an arc shape, and are formed almost at the center of the flat members 4 and 6. Through-hole. The effects of the through holes 4b and 6b different from those described above will be described in detail in the section of the bearing 8 below.

  In the bearing device 1 of this aspect, the discharge ports 4a to 7a provided in the storage member 2 are formed by cutting out the four corners of the flat plate members 4 to 7 as described above, but the discharge ports for discharging the plating bath are What is necessary is just to open to the bottom face 2b of the hollow part 2a, and you may comprise in a through-hole shape. Hereinafter, first to third modified examples related to the discharge port for discharging the plating world will be described with reference to FIG. FIGS. 7A to 7C are bottom views of the storage members according to the first to third modifications. In addition, in FIG. 7 which shows the storage member of the 1st-3rd modification from which only the aspect of a discharge port differs, the same code | symbol is attached | subjected about the same component as the said storage member 2, and detailed description is abbreviate | omitted. (The same applies to the bearing devices according to the fourth to eleventh modifications described with reference to FIGS. 8 to 12).

  The storage member 19 according to the first modification shown in FIG. 7 (a) is a flat plate disposed below, with no discharge port provided in the flat members 12, 14, and 21 disposed on the side and rear. Only the shaped member 20 is formed with a discharge port 20a that opens to the bottom surface of the hollow portion. The discharge port 20a of this aspect is a through-hole having a substantially cylindrical inner surface that penetrates the flat plate member 20 in the Z-axis direction, and has three holes at both ends and the center portion of the flat plate member 20 in the X-axis direction. In the direction, two holes are provided at both end portions of the flat plate-like member 20, for a total of six holes.

  The storage member 23 according to the second modified example shown in FIG. 7B is provided with discharge ports in the flat plate members 12, 14, and 21 arranged on the side and rear, similarly to the storage member 19. Instead, a discharge port 24a that opens to the bottom surface of the hollow portion is formed only in the flat plate-like member 24 disposed below. The discharge port 24a of this embodiment is a long hole-like through hole extending in the X-axis direction that penetrates the flat plate member 24 in the Z-axis direction, and two holes are provided at both ends of the flat plate member 24 in the Y-axis direction. .

  In the storage member 26 according to the third modification shown in FIG. 7C, the flat plate members 12, 14, and 21 disposed on the side and the rear are provided with discharge ports, similarly to the storage member 19. Instead, the discharge port 27a that opens to the bottom surface of the hollow portion is formed only in the flat plate-like member 24 disposed below. The discharge port 27a of this embodiment is a long hole-like through hole extending in the Y-axis direction that penetrates the flat plate member 24 in the Z-axis direction, and five holes are equally spaced between both ends of the flat plate member 24 in the X-axis direction. Is provided.

[bearing]
The bearing 8 will be described. As shown in FIG. 4A, the bearing 8 of this embodiment having a substantially quadrangular prism shape having four outer surfaces 8b to 8e extending in the X-axis direction is a cross-sectional view orthogonal to the axis I, that is, a YZ plane. In the center portion, an insertion portion 8a having an inner peripheral surface extending in the X-axis direction and having a substantially cylindrical shape is formed. The shaft portion 97a of the substantially cylindrical support roll is inserted into the insertion portion 8a from one end where the insertion portion 8a opens, and the outer peripheral surface thereof slides while being in contact with the inner peripheral surface of the insertion portion 8a. .

  The form which looked at the bearing 8 of this aspect from the side is demonstrated. As shown in FIG. 3, convex portions 8 f are provided on the four outer surfaces 8 b to 8 e of the bearing 8 of this aspect. The outer edge shape of the convex portion 8f is an arc shape that is convex outward, and is the same as the shape shown in FIG. 3 at any location on the Z-axis and the Y-axis. That is, the convex portion 8f has a substantially bowl shape as a whole, and the surface, which is also the outer surfaces 8b to 8e of the bearing 8, is a curved surface that is convex outward. And as shown to Fig.4 (a) which is CC sectional drawing which cut | disconnected the center of the bearing 8 shown in FIG. 3 in the X-axis direction, the axial part 8 is the top of the convex-shaped part 8f, and the accommodation member 2 of FIG. It is in contact with the inner surfaces 3c to 6c. Further, as shown in FIG. 4 (b), which is a view of the rear end portion of the bearing 8 shown in FIG. Is formed. In addition, in the bearing device 1 of this aspect, as shown in FIG. 3, a convex portion 8 h whose outer surface has an arc shape or a substantially hemispherical shape is formed on the rear side of the bearing 8 in the X-axis direction. The shape portion 8h is also in contact with the inner surface 7c of the flat plate-like member 7 disposed behind the storage member 2, and a gap 2d is formed between them. The convex portion 8f is not necessarily provided on all the four outer surfaces 8b to 8e of the bearing 8, and corresponds to the state of the plating bath remaining between the storage member 2 and the bearing 8, and is necessary. What is necessary is just to provide in the outer surfaces 8b-8e.

  Here, as shown in FIG. 8 which is a front sectional view of the bearing device 9 which is the fourth modified example of the bearing device 1, the outer surfaces 15 b to 15 e of the bearing 15 and the inner surfaces 11 c to 14 c of the storage member 10 are both flat. When the bearing 15 is assembled into the storage member 10, both may be brought into close contact with each other over the entire surface. In that case, the plating bath flows down a slight gap between the two, and the plate-like member 13 below is flowed down. It is discharged to the outside through the formed discharge port 13a.

  However, like the bearing device 1 of this embodiment shown in FIG. 3, the gaps 2c and 2d are provided between the bearing 8 and the storage member 2 to enter between the outer surfaces 8b to 8e and 8h and the inner surfaces 3c to 7c. The plated bath is desirable because it flows down through the gaps 2c and 2d provided between the two and is more smoothly discharged from the discharge ports 4a to 7a. In addition, since the top portions of the convex portions 8f and 8h of the bearing 8 are configured to contact the inner surfaces 3c to 7c as described above, the plating bath existing at the contact portion between the top portion and the inner surfaces 3c to 7c can be hardly discharged. There is sex. In order to discharge the plating bath that has entered the contact portion, as explained in the section of the housing member, the through holes 4b and 6b that correspond to the position of the top portion and are formed in the substantially central portion of the flat members 4 and 6 are formed. Is provided.

  With reference to FIGS. 9 to 11, fourth to ninth modifications in which the gap is formed between the bearing and the housing member in order to cause the plating bath to flow down are different from the bearing device 1.

  FIG. 9A shows a front view of the bearing device 28 according to the fifth modification. The bearing device 28 according to the present aspect has a hemispherical shape in which the bearing 29 is formed so as to protrude from the flat outer surfaces 29b to 29e facing the inner surfaces 3c to 6c of the storage member 2 and the central portions of the outer surfaces 29b to 29e. This is different from the bearing device 1 in that it has a convex portion 29f. And the top part of the hemispherical convex part 29f of the bearing 29 is arrange | positioned so that the inner surfaces 3c-6c of the storage member 2 may be contact | connected, and the clearance gap 2c is formed between the bearing 29 and the storage member 2. FIG. According to the bearing device 28, since the contact area between the inner surfaces 3c to 6c of the storage member and the convex portion 29f is small, the gap between the outer surfaces 29b to 29e of the bearing 29 and the inner surfaces 3c to 6c of the storage member is wide. This is advantageous from the viewpoint of the discharge property of the plating bath.

  FIG. 9B shows a side sectional view of the bearing device 30 according to the sixth modification. In FIG. 9B, the right end portion of the bearing 31 is a side view. As shown in the drawing, the bearing device 30 of this aspect has four planar outer surfaces 31b to 31 whose bearings 31 face the inner surfaces 3c to 6c of the storage member 2 (the inner surfaces 4c and 6c on the side are not shown). 31e (the outer surface 31c on the left is not shown), and a bearing device in that each of the outer surfaces 31b to 31e has a single protruding portion 31f / 31s formed so as to protrude along the Z-axis or the Y-axis. 1 and different. The tops of the convex portions 31 f and 31 s of the bearing 31 are disposed so as to contact the inner surfaces 3 c to 6 c of the storage member 2, and a gap 2 c is formed between the bearing 31 and the storage member 2. In addition, like the convex part 31s formed in the outer surface 31e of the bearing 31 of this aspect, according to the discharge | emission state of a plating bath, a convex part is provided in the position different from the other convex parts 31f in the X-axis direction. Also good.

  FIG. 9C shows a side sectional view of the bearing device 32 according to the seventh modification. The bearing device 32 of this aspect is basically the same configuration as the bearing 8, but the top of the arcuate convex portion 33 f is on the left side by a distance h from the center F of the bearing 33 in the X-axis direction. The bearing device 1 is different from the bearing device 1 in that it is arranged at a position shifted to the opening side of the insertion portion 8a into which the shaft portion 97a is inserted. According to the bearing device 32, in the X-axis direction, the gap 2g behind the hollow portion 2a of the storage member 2 where the plating bath is difficult to be discharged can be made larger than the front gap 2c. Is advantageous. Further, the thickness i of the left end portion of the bearing 33 that is relatively susceptible to damage due to insertion of the shaft portion 97a into the insertion portion 8a of the bearing 33 or thermal deformation of the shaft portion 97a due to a high-temperature plating bath can be increased. It is advantageous in terms of life extension.

  A side sectional view of the bearing device 34 according to the eighth modification is shown in FIG. The bearing device 34 of this aspect is different from the bearing device 1 in that a convex portion is provided on the storage member 35. That is, the bearing 41 of this aspect has the insertion part 8a in which the axial part 97a is inserted similarly to the said bearing 8, However, The four outer surfaces 41b-41e (The side outer surfaces 41c * 41e are not shown) The planes are orthogonal to each other. On the other hand, the support member 35 is combined with a substantially U-shape of five flat plate members 36 to 40 (the side flat plate members 37 and 39 are not shown) in the same manner as the support member 2, and the bearing 41. The inner surface 36c to 39c (37c and 39c are not shown) of the storage member 35 facing the outer surfaces 41b to 41e of the bearing 41, respectively. The convex part 36d which the outer surfaces 41b-41e of 41 and the top part contact | connect is provided.

  Even in the configuration in which the convex portion 36d is provided on the inner surfaces 36c to 39c of the support member 35 as described above, the gap 2c is formed between the bearing 41 and the storage member 35 in the same manner as the bearing device 1. The plating bath remaining between the bearing 41 and the storage member 35 can be smoothly discharged through the gap 2c. In addition, since the outer surfaces 41b to 41e are flat, the bearing 41 of this aspect can be easily formed by machining or the like, and is particularly advantageous when the bearing 41 is made of difficult-to-work ceramics.

  FIG. 10B shows a side sectional view of the bearing device 42 according to the ninth modification. The bearing device 42 of this aspect is different from the bearing device 1 in that a gap in which the plating bath flows down by the concave portion is formed instead of the convex portion. That is, the storage member 43 of this aspect is combined with the substantially U-shape of the five flat plate members 44 to 48 (the side flat plate members 45 and 47 are not shown), like the support member 2. The hollow portion 2a for housing the bearing 49 is formed, but the inner surfaces 44c to 47c (45c and 47c are not shown) of the housing member 43 facing the outer surfaces 49b to 49e of the bearing 49 are arranged in the X-axis direction. Are provided with two concave portions 44e formed at both ends thereof. The recess 44e extends in a groove shape so as to penetrate the flat plate members 44 to 47 in the Y-axis and Z-axis directions. When the bearing 49 is inserted into the hollow portion 2a of the storage member 43, the inner surfaces 44c to 47c of the storage member 43 are arranged so that the planar outer surfaces 49b to 49e of the bearing 49 are in contact with each other. A gap 2c is formed by 49e and the concave portion 44e. The shape, the number of strips, and the arrangement of the concave portion 43e are not particularly limited. However, in order to improve the discharge performance of the plating bath, it is preferable to provide a plurality of strips in the X-axis direction. A concave portion 49p having the same form as the concave portion 44e of the storage member 43 may be provided on the outer surfaces 49b to 49e to form the gap 2c.

  A front view of the bearing device 52 according to the tenth modification is shown in FIG. The bearing device 52 of this embodiment is different from the bearing device 1 in that two of the four outer surfaces of the bearing are not in close contact with the inner surface of the storage member. That is, in the bearing device 52 of this aspect, when the bearing 8 is stored in the hollow portion 2a of the storage member 53, the two inner surfaces 54c and 55c of the storage member 53 do not contact the two outer surfaces 8b and 8c of the bearing 8. A gap 2c having a width a in the Z-axis direction and a gap 2c having a width b in the Y-axis direction are formed therebetween, and the other two outer surfaces 8d and 8e of the bearing 8 are respectively connected to the two inner surfaces 56c and It is configured to contact 57c. According to the bearing device 52, the plating bath remaining between the storage member 53 and the bearing 8 flows down through the gap 2c and is discharged from the discharge port opened in the bottom surface 2b of the hollow portion 2a. In the bearing device 52 of this aspect, the widths a and b of the gaps 2c are relatively large, and are fixed members disposed on the flat plate members 54 and 55 in order to fix the bearing 8 stably in the hollow portion 2a. The bearing 8 is fixed by a certain screw 58/59. However, since the force is stably applied to the shaft portion 97a of the support roll in the direction indicated by the arrow E due to the tension applied to the steel plate, the screw 58 is used when the width ab of the gap 2c is small. The bearing 8 does not have to be fixed at 59.

  Next, in the bearing 8 which is a preferred embodiment, a configuration relating to the circulation of a plating bath which is a lubricating medium interposed between the bearing 8 and the shaft portion 97a will be described. As shown in FIG. 3, the bearing 8 according to this aspect includes a thrust receiver for receiving the right end surface of the shaft portion 97a of the support roll that moves in the X-axis direction during operation and restricts movement in the X-axis direction. The bearing end 8k is arranged at the right end. On the other hand, when the bearing end 8k is provided and the right end of the bearing 8 is closed as described above, the plating bath remains inside the bearing 8 when the bearing device 1 is pulled up, and the bearing in the process where the remaining plating bath cools and solidifies. 8 may be damaged. For this reason, as shown in the figure, a through hole-shaped flow hole 8j communicating with the hollow portion 8a of the bearing 8 is provided at the bearing end 8k, and the plating bath flowing into the bearing 8 is discharged to the outside through the flow hole 8j. It is desirable to configure so that. Furthermore, it is preferable that the lower surface of the flow hole 8j is disposed below the lower surface of the sliding surface of the bearing 8 (the inner surface of the insertion portion 8a) in the Z-axis direction. The through hole 8j for discharging the plating bath from the inside of the bearing 8 is not limited to the form of FIG. 3, but is a side sectional view of a bearing device 50 which is an eleventh modification of the bearing device 1 as shown in FIG. In addition, the bearing 51 may be provided with a through hole 51j penetrating in the vertical direction so as to communicate with the hollow portion 8a.

  Also, as shown in FIG. 3, when the right end of the bearing 8 is closed by the bearing end 8h, the plating bath as a lubricating medium is not smoothly supplied to the sliding surfaces of the bearing 8 and the shaft portion 97a, and dross or the like There is a possibility that foreign matter stays inside the bearing 8. For this reason, it is preferable to provide the bearing 8 with a hot water reservoir 8i that is disposed so as to be interposed between the right end of the insertion portion 8a and the bearing end portion 8k and has a larger inner diameter than the insertion portion 8a. With this configuration, even when the shaft portion 97a is inserted into the bearing 8, the plating bath circulates between the hot water pool portion 8i and the outside through the flow hole 8j, and smoothly removes dross as a lubricating medium. Will function.

  The structure which prevents the damage of the bearing 8 by the deformation | transformation of the axial part 97a which arises by immersing in the hot plating bath in the bearing 8 which is a preferable aspect is demonstrated. As shown in FIG. 3, in the X-axis direction, the bearing 8 has an R surface at a corner portion at the left end (one end) and the right end (the other end) of the insertion portion 8a, that is, a corner portion of the opening end of the insertion portion 8a. It is preferable to provide 8 g. Thereby, it can prevent that the outer peripheral surface of the axial part 97a inclined by deformation | transformation is pressed on the corner | angular part of the opening end of the insertion part 8a, and the corner | angular part is damaged. The R surface 8g formed at the corner may be a C surface.

  Subsequently, the form which looked at the bearing 8 of this aspect from the front is demonstrated. As shown in FIGS. 4 (a) and 4 (b), the bearing 8 has a notch portion 8n formed by notching two lower corners of the bearing 8 with a notch surface 8m. The openings 4a to 7a (the opening 7a is not shown) are provided below or on the side corresponding to the notch 8n. Thus, by providing the notch part 8n in the lower part of the bearing 8, it forms between each of the two outer surfaces 8c and 8e on the side of the bearing 8 and the two inner surfaces 4c and 6c on the side of the storage member 2. The plating bath flowing through the gap is discharged from the discharge ports 4a to 7a through the notch 8n. Here, since the notch 8n is a large space with respect to the gap between the bearing 8 and the storage member 2, the plating bath flowing through the gap is supplied to the notch 8n without stagnation, and thereafter It is smoothly discharged from the discharge ports 4a to 7a provided at the position corresponding to the notch 8n. Furthermore, as shown in FIG. 5 which is a cross section along the plane B of FIG. 1, the notch 8 n provided in the bearing 8 becomes a gap between the bearing 8 extending in the X-axis direction and the storage member 2. Therefore, it is possible to reduce the area of the opposing portion of the outer surfaces 8c and 8e of the bearing 8 with respect to the inner surfaces 4c and 6c of the storage member 2 shown in FIG. It becomes.

  Further, as shown in FIGS. 4A and 4B, the bearing 8 of this embodiment has an inclined surface 8L that is formed at the corners of the upper two corners and is inclined downward. By providing the inclined surface 8L on the upper portion of the bearing 8 in this manner, the plating bath remaining in the gap formed between the surface 8b and the inner surface 3c disposed above the bearing 8 and the storage member 2 is inclined. It flows downward along the surface 8L and is discharged through the discharge ports 4a to 7a.

  Further, by providing the inclined surface 8L and the notch surface 8m on the upper and lower portions of the bearing 8 as described above, a secondary effect that damage to the bearing 8 can be prevented is produced. That is, when the adjacent outer surfaces 8b to 8e of the bearing 8 are directly connected, an acute corner portion is generated at the connection portion. Cracks or the like are likely to be caused at the corners due to rapid heating / cooling during immersion and lifting of the bearing device 1 in the plating bath, and the bearings 8 are likely to be damaged. On the other hand, damage to the bearing 8 can be suppressed by providing the inclined surface 8L and the notch surface 8m as in the bearing 8 of this aspect and eliminating the sharp corners. Although the shape of the inclined surface 8L and the notch surface 8m is not particularly limited, the shape of the inclined surface 8L and the notch surface 8m is reduced in order to reduce the sudden change portion of the thickness and reduce the thermal stress generated by heating and cooling. It is desirable that the arc shape bulges outward.

[Bearing material composition]
The bearing 8 immersed in the plating bath and sliding with the shaft portion 97a is required to have corrosion resistance against the plating bath and wear resistance against sliding. Therefore, the bearing 8 is made of ceramics. Hereinafter, the suitable example is demonstrated about the ceramics which comprise the bearing 8. FIG.

  Ceramics include alumina, zirconia, silica and other oxide ceramics, zirconium boride, titanium boride, boride depending on the thermal shock resistance and corrosion resistance required by the operating conditions of the support roll and other operating conditions. Boron and other boride ceramics, silicon carbide / boron carbide and other carbide ceramics, or inorganic materials such as carbon may be used. The bearing 3 needs to be excellent in thermal shock resistance because it is rapidly heated / cooled when immersed in the plating bath and taken out. Therefore, as the ceramic constituting the bearing 3, silicon nitride / aluminum nitride and other nitride ceramics having high thermal conductivity are preferable and have high resistance to erosion and wear against molten metal as a plating bath. Silicon nitride ceramics excellent in high temperature strength are particularly preferable. Hereinafter, silicon nitride ceramics suitable for constituting the bearing 3 may be the same as those described in JP-A-2001-335368.

  Aluminum and oxygen present in the silicon nitride ceramic serve as a phonon scattering source and reduce the thermal conductivity. Silicon nitride ceramics are composed of silicon nitride particles and surrounding grain boundary phases, and aluminum and oxygen are contained in these phases. Since aluminum has an ionic radius close to that of silicon, it easily dissolves in silicon nitride particles. Due to the solid solution of aluminum, the thermal conductivity of the silicon nitride particles themselves is lowered, and the thermal conductivity of the silicon nitride ceramics is significantly lowered. Therefore, it is desirable to reduce the aluminum content in the silicon nitride ceramics as much as possible.

  Most of the oxygen in the oxide added as a sintering aid is present in the grain boundary phase. In order to achieve high thermal conductivity of silicon nitride ceramics, it is necessary to reduce the amount of grain boundary phase having lower thermal conductivity than silicon nitride particles. The lower limit of the addition amount of the sintering aid is such an amount that a sintered body having a relative density of 8.5% or more can be obtained. It is desirable to reduce the amount of oxygen in the grain boundary phase by making the addition amount of the sintering aid as small as possible within this range.

When silicon nitride powder with a small amount of oxygen is used as a raw material, the amount of oxygen in the grain boundary phase can be reduced, so the amount of grain boundary phase itself can be reduced, and high thermal conductivity of the sintered body can be achieved. It becomes difficult to sinter due to a decrease in the amount of SiO ₂ produced in the process. However, when MgO, which is superior in sinterability to other oxides, is used as a sintering aid, the amount of sintering aid added can be reduced and a dense sintered body can be obtained. As a result, the thermal conductivity of the sintered body is dramatically increased.

  Examples of sintering aids that can be added together with magnesium include Group 3 of the periodic table such as Y, La, Ce, Nd, Pm, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, and Lu (described later). Is mentioned. Among these, Y, La, Ce, Gd, Dy, and Yb are preferable in that the sintering temperature and pressure do not become too high.

  The thermal conductivity of the silicon nitride ceramic constituting the bearing 8 at room temperature is 50 W / (m · K) or more, more preferably 60 W / (m · K) or more. Accordingly, the oxygen content in the silicon nitride ceramic is 5% by weight or less to obtain a thermal conductivity of 50 W / (m · K) or more, and a thermal conductivity of 60 W / (m · K) or more. Is 3% by weight or less. The oxygen content in the silicon nitride particles is 2.5% by weight or less for obtaining a thermal conductivity of 50 W / (m · K) or more, and a thermal conductivity of 60 W / (m · K) or more. Is 1.5% by weight or less. Furthermore, the aluminum content in the silicon nitride ceramic is 0.2% by weight or less for obtaining a thermal conductivity of 50 W / (m · K) or more, and a thermal conductivity of 60 W / (m · K) or more. Is 0.1% by weight or less.

  The total amount of magnesium MgO and Group 3 element oxides in the silicon nitride ceramic is preferably 0.6 to 7% by weight. When the total amount is less than 0.6% by weight, the relative density of the sintered body is less than 95%, which is insufficient. On the other hand, if it exceeds 7% by weight, the amount of the grain boundary phase having a low thermal conductivity becomes excessive, and the thermal conductivity of the sintered body becomes less than 50 W / (m · K). The MgO + Group 3 element oxide is more preferably 0.6 to 4% by weight.

  The weight ratio of MgO / Group 3 element oxide is preferably 1 to 70, more preferably 1 to 10, and most preferably 1 to 5. If the MgO / Group 3 element oxide is less than 1, the ratio of the rare earth oxide in the grain boundary phase is too high, and it becomes difficult to sinter and a dense sintered body cannot be obtained. On the other hand, if the MgO / Group 3 element oxide exceeds 70, the diffusion of Mg during sintering cannot be suppressed, and color unevenness occurs on the surface of the sintered body. When the MgO / Group 3 element oxide is in the range of 1 to 70, the thermal conductivity is significantly increased by sintering at 1650 to 1850 ° C. When the sintered body is heat-treated at 1800 to 2000 ° C., the thermal conductivity is further increased. The increase in thermal conductivity by heat treatment is due to the growth of silicon nitride particles and volatilization of MgO having a high vapor pressure.

  The total amount of aluminum, magnesium, and Group 3 elements in the periodic table in the silicon nitride particles is preferably 1.0% by weight or less.

  Of the β-type silicon nitride particles in the silicon nitride sintered body, when the proportion of β-type silicon nitride particles having a minor axis diameter of 5 μm or more exceeds 10% by volume, the thermal conductivity of the sintered body is improved. Since the coarse particles introduced into the film act as a starting point of fracture, the fracture strength is remarkably lowered, and a bending strength of 700 Mpa or more cannot be obtained. Therefore, the ratio of β-type silicon nitride particles having a minor axis diameter of 5 μm or more in the β-type silicon nitride particles in the silicon nitride sintered body is preferably 10% by volume or less. Similarly, the β-type silicon nitride particles preferably have an aspect ratio of 15 or less in order to prevent the coarse particles introduced into the structure from acting as a starting point of fracture.

The silicon nitride ceramic forming the bearing 8 needs to have a sufficient resistance to sudden temperature changes. The resistance to sudden temperature changes is the following formula (1):
R = αc (1−ν) / Eα (1)
(However, αc: Four-point bending strength (MPa) at normal temperature, ν: Poisson's ratio at normal temperature, E: Young's modulus (MPa) at normal temperature, α: Average thermal expansion coefficient from normal temperature to 800 ° C)
The coefficient R represented by the coefficient represented by is preferably 600 or more, and more preferably 700 or more. If the coefficient R is less than 600, the bearing 3 may be broken. The coefficient R is the four-point bending strength αc (MPa) at room temperature measured for the specimen cut out from the bearing 3, the Poisson's ratio ν at room temperature, the Young's modulus E (MPa) at room temperature, and the average heat from room temperature to 800 ° C. Obtained from the expansion coefficient α.

  Ceramics originally have a low wettability with the plating bath and may not be necessary. However, when the ceramics constituting the bearing 8 have a high wettability with the plating bath, the gap between the bearing 8 and the housing member 2 is not necessary. From the viewpoint of allowing the plating bath to flow smoothly, it is desirable that the plating bath does not easily adhere to the outer surfaces 8b to 8e of the bearing 8, and a film such as ceramic or cermet having low wettability with the plating bath is formed on these. It is desirable to keep it.

1 (9, 18, 22, 25, 28, 30, 32, 34, 42, 50, 52) Bearing device 2 (10, 19, 23, 26, 35, 43, 53, 57) Storage member 2a Hollow portion 2b Bottom surface 2c (2d) Clearance 3 (4-7) Flat plate member 3a (4a-7a, 3d, 4d, 6d, 7d) Opening 8 (15, 29, 31, 33, 41, 49, 51) Bearing 8a Insertion portion 8b (8c to 8e) External surface 8f (29f, 31f, 31s, 33f, 36d) Convex part 49p Concave part 8i Hot water reservoir 8j (51j) Discharge hole 90 Molten metal plating apparatus 91 Molten metal plating bath 97 Support roll 98 Sink Roll W Steel sheet

Claims (13)

A bearing device for a molten metal plating bath that rotatably supports a shaft portion of a rotating body immersed in the molten metal plating bath,
A metal bearing having a ceramic bearing having an insertion portion into which the shaft portion is inserted from one end and a member disposed so as to block one opening and housing the bearing through the other opening. A storage member,
The housing member may have a discharge opening of a molten metal plating bath that is open to the bottom surface of the hollow portion,
The bearing has a bearing end disposed so as to close the other end of the insertion portion, and the bearing end is melted to open on the insertion portion side of the bearing end portion and on the storage member side of the bearing end portion. A bearing device for a molten metal plating bath, wherein a circulation hole for the metal plating bath is formed . The bearing device for a molten metal plating bath according to claim 1, wherein the insertion portion has a cylindrical shape. The bearing device for a molten metal plating bath according to claim 1 or 2 , wherein the bearing has a notch portion formed in a lower portion thereof, and the discharge port is formed at a position corresponding to the notch portion. The bearing device for a molten metal plating bath according to any one of claims 1 to 3 , wherein the bearing has an inclined surface formed in an upper portion thereof and inclined downward. The bearing device for a molten metal plating bath according to any one of claims 1 to 4 , wherein the housing member has an opening communicating with the hollow portion formed in an upper portion or a side portion thereof. The bearing device for a molten metal plating bath according to any one of claims 1 to 5, wherein the bearing has a hot water pool portion disposed so as to be interposed between the insertion portion and the bearing end portion. The bearing device for a molten metal plating bath according to claim 6, wherein a dimension in a radial direction of an inner surface of the hot water pool portion is larger than an inner diameter of the insertion portion. The bearing device for a molten metal plating bath according to any one of claims 1 to 7 , wherein a gap is formed between an inner surface of the hollow portion and an outer surface of the bearing. The bearing device for a molten metal plating bath according to claim 8 , wherein the gap is formed by a convex portion formed on an inner surface of the hollow portion or an outer surface of the bearing. The bearing device for a molten metal plating bath according to claim 8 , wherein the gap is formed by a concave portion formed on an inner surface of the hollow portion or an outer surface of the bearing. The bearing device for a molten metal plating bath according to claim 9, wherein the convex portion is formed on four surfaces. The bearing device for a molten metal plating bath according to claim 10, wherein the concave portion is formed on four surfaces. The bearing device for a molten metal plating bath according to any one of claims 1 to 12, wherein a film having low wettability with a molten metal plating bath is formed on an outer surface of the bearing or an inner surface of a hollow portion of the housing member.

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