Bearing for ship propulsion shaft and bearing reconditioning method

Abstract

The present invention relates to a barrel-type bearing which uses water lubrication, which supports a propulsion shaft of a marine vessel, and in which a plurality of arc pieces are held and retained at the inner circumferential surface of the bearing. A bearing according to the present invention has, at the inner circumferential surface of a cylindrical shell that supports a propulsion shaft of a marine vessel, a pair of positioning plates which are fixed opposite each other on the horizontal axis of the shell, a key member which is fixed to the bottom point Pb part of the shell, a bottom arc piece which engages with the key member, arc pieces which are provided to an upper part of the positioning plates, and arc pieces which are provided to a lower part. The horizontal axis is orthogonal to the center-of-gravity line of the propulsion shaft in a transverse section of the shell. This bearing makes it possible to easily hold and retain arc pieces at the inner circumferential surface of the bearing, and makes it possible to transfer arc pieces that are worn and arc pieces that are not worn to easily restore the bearing.

Description

[Technical Field]

[0001] The present invention relates to a water-lubricated bearing that supports a propeller shaft of a ship, and more particularly to a barrel-type bearing and a bearing reconditioning method. [Background technology]

[0002] Water-lubricated bearings, which use water lubrication such as water or seawater for ship propulsion shafts, are gaining attention from the perspective of environmental protection compared to oil-lubricated bearings. According to Non-Patent Document 1, which summarizes the structure and characteristics of such bearings, water-lubricated bearings are being used in place of conventional oil-lubricated bearings for small and medium-sized ships, and it is expected that the transition to water-lubricated bearings will progress in large ships as well in the future. Various water-lubricated bearings have also been proposed in patent documents.

[0003] For example, Patent Document 1 proposes a bearing comprising a pair of positioning plates and a plurality of closed arcuate pieces and gap-type arcuate pieces disposed on the inner circumferential surface of a cylindrical shell supporting a ship's propeller shaft, the positioning plates being fixed at opposing positions on the horizontal axis of the shell, the closed arcuate pieces being disposed on the underside of the shell below the positioning plates and bearing the load of the propeller shaft, the gap-type arcuate pieces being disposed on the upper surface of the shell opposite the closed arcuate pieces and having grooves formed on both side edges for circulating cooling water, and both the closed arcuate pieces and the gap-type arcuate pieces having a three-layer structure consisting of a sliding layer, an intermediate layer made of an elastic material, and a base that is in close contact with the inner circumferential surface of the shell. This bearing has a sliding layer made of a material with a smooth surface and excellent wear resistance and heat resistance, and an elastic layer that can even out the load from the propeller shaft, and is said to have low friction, wear resistance, and durability, and also has excellent corrosion resistance because the elastic layer is protected from water or seawater.

[0004] Patent Document 2 proposes a split bearing characterized in that the bearing member has a sliding material made of rubber to form a first bearing member (20a), the bearing member provided in the approximately lower half (L) of the shell has a sliding material made of fluororesin to form a second bearing member (20b), and stoppers (30, 30a) are provided between the approximately upper and lower halves of the shell to prevent circumferential movement of the bearing member. This split bearing is said to have less sliding resistance to the propeller shaft than conventional split bearings, improving the fuel efficiency of ships. Furthermore, it is stated that split bearings have recently been used as bearings to support ship propeller shafts, and that split bearings have advantages such as easy repair, since only the bearing member that is most heavily worn can be replaced. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2021 / 260965 [Patent Document 2] Utility Model Registration No. 3183964 [Non-Patent Document 1] Fumitaka Yoshikawa, Yoshimasa Kanaka, "Tribology of Seawater-Lubricated Plain Bearings," Tribologist, Vol. 60, No. 12 (2015) Summary of the Invention [Problem to be solved by the invention]

[0006] The water-lubricated bearings shown in Patent Documents 1 and 2 are not only highly wear-resistant, but also have the advantage of allowing the bearing components (arc pieces) that make up the bearing to be stored in reserve and only those bearing components that are severely worn to be replaced. However, the range of bearing components that need to be replaced is not necessarily narrow, and the replacement process for bearing components is not easy. Meanwhile, bearing components may be unexpectedly damaged due to misalignment, propeller shaft whirring, or propellers operating half-submerged, requiring emergency response, and rapid response is required in such cases. Furthermore, bearing wear often progresses in the lower stern area, which supports most of the propeller load. For this reason, from the perspective of safety and propulsion efficiency, an upper limit on the amount of wear in this area is generally set, and appropriate management of that wear is required.

[0007] In response to these conventional problems and demands, the present invention aims to provide a water-lubricated bearing that not only has excellent wear resistance and durability, but also allows the bearing components that make up the bearing to be easily and quickly replaced without the need for spare parts, and to provide a method for reconditioning the bearing. [Means for solving the problem]

[0008] The bearing according to the present invention comprises a pair of positioning plates fixed to the inner peripheral surface of a cylindrical shell supporting a ship's propulsion shaft on the horizontal axis of the shell in opposing positions, an anchor member fixed to the lowest point Pb of the shell, and arc pieces, the arc pieces including a bottom arc piece fitted with the anchor member, an upper arc piece disposed on the upper portion of the positioning plate, and a lower arc piece disposed on the lower portion. Here, the horizontal axis refers to an axis perpendicular to the center of gravity of the propulsion shaft in a cross section of the shell.

[0009] In the above invention, it is preferable that the arcuate piece in contact with the lower edge of the arcuate piece in contact with the lower edge of the positioning plate has a shape that can be exchanged with the bottom arcuate piece.

[0010] In the above invention, the bottom arcuate piece may have a groove in the center or side edge of the bottom that fits onto the anchor member.

[0011] In the above invention, it is preferable that the upper arcuate piece is pressed against and held against the upper inner peripheral surface of the shell via a positioning plate, and the lower arcuate piece is pressed against and held against the lower inner peripheral surface of the shell via the positioning plate and the bottom arcuate piece.The positioning plate is preferably a strip-shaped body formed by engaging an upper plate having a shell fixing means with a lower plate held against the inner peripheral surface of the shell via the upper plate.

[0012] Furthermore, it is preferable that the lower plate can be pulled out from the shell with a predetermined pulling force in a state where all the arc pieces are disposed on the inner peripheral surface of the shell.

[0013] Preferably, the upper plate is fitted to the arcuate piece in contact therewith, and the lower plate is fitted to the arcuate piece in contact therewith.

[0014] It is also preferable that the number of upper arcuate pieces, including the arcuate piece at the top of the shell, is an odd number.

[0015] In the above invention, the upper arcuate piece may be a gap-type arcuate piece, and the lower arcuate piece may be a gap-type arcuate piece or a closed arcuate piece.

[0016] The bearing reconditioning method of the present invention is a bearing reconditioning method for a cylindrical shell supporting a ship's propulsion shaft, which has a pair of positioning plates fixed to the inner peripheral surface of the shell on a horizontal axis facing each other, an anchor member fixed to the shell's lowest point Pb, and arc pieces, the arc pieces including a bottom arc piece that fits onto the anchor member, an upper arc piece disposed on the upper portion of the positioning plate, and a lower arc piece disposed on the lower portion, and when the wear depth of the lowest point Pb of the lower arc piece at the stern side of the lower arc piece W reaches a predetermined value, the arc pieces are rearranged so that the less worn arc pieces 15 are positioned closer to the lowest point Pb on the inner peripheral surface of the shell 11, and the more worn arc pieces 15 are positioned farther from the lowest point Pb. Here, the horizontal axis refers to an axis perpendicular to the center of gravity of the propulsion shaft in the cross section of the shell.

[0017] In the above bearing reconditioning method, the rearrangement of the arc pieces is preferably carried out so as to ensure continuity of the wear cross section of the worn portion W.

[0018] The bearing according to the present invention may also be configured as a bearing comprising a pair of positioning plates secured to the inner peripheral surface of a cylindrical shell supporting a ship's propeller shaft, facing each other on the horizontal axis of the shell, an anchor member secured to the shell's lowest point Pb, and arc pieces, the positioning plate being a strip-shaped body formed by engaging an upper plate having a shell securing means with a lower plate held to the inner peripheral surface of the shell via the upper plate, the arc pieces including a bottom arc piece fitted with the anchor member, an upper arc piece disposed on the upper portion of the positioning plate, and a lower arc piece disposed on the lower portion, the lower arc piece being in contact with the lower edge of the arc piece that is in contact with the lower edge of the positioning plate and further comprising a substitute arc piece that can be replaced with the bottom arc piece. Here, the horizontal axis refers to an axis perpendicular to the center of gravity of the propeller shaft in a cross section of the shell.

[0019] Furthermore, the bearing reconditioning method of the present invention is carried out by first withdrawing the lower plate from the shell, taking the right-side substitute circular arc piece to the bottom circular arc piece as the right-side circular arc piece group and the left-side substitute circular arc piece to the bottom circular arc piece as the left-side circular arc piece group, and then withdrawing the right-side circular arc piece group as a group from the shell, reversing the axial direction and reinstalling the group as such in the shell, and withdrawing the left-side circular arc piece group as a group from the shell, reversing the axial direction and reinstalling the group as such in the shell, thereby rearranging the circular arc pieces. Here, the vertical axis refers to the axis opposite to the direction of the center of gravity of the propeller shaft which is perpendicular to the horizontal axis, and the right side of the vertical axis is referred to as the right side of the shell cross section.

[0020] In addition, the bearing reconditioning method of the present invention is carried out by first withdrawing the lower plate from the shell, then withdrawing the right group of arc pieces from the shell as a group, reversing the axial direction and reinstalling the group as a group in the shell, and withdrawing the left group of arc pieces from the shell as a group, reversing the axial direction and reinstalling the group as a group in the shell, thereby rearranging the arc pieces. Here, the vertical axis refers to the axis opposite to the direction of the center of gravity of the propeller shaft, which is perpendicular to the horizontal axis, and the right side of the vertical axis refers to the right side of the shell cross section. [Effects of the Invention]

[0021] The bearing according to the present invention allows for easy and quick arrangement of arc pieces on the inner peripheral surface of the shell, and is excellent in wear resistance and durability. The bearing reconditioning method according to the present invention involves rearranging arc pieces that are severely worn or damaged in combination with arc pieces that are in good condition or have little wear or damage, making it possible to recondition bearings easily and quickly without using spare parts. [Brief explanation of the drawings]

[0022] [Figure 1]1A is a front view and a side view of a bearing in which the arcuate pieces are made up of only gap-type arcuate pieces, and FIG. 1B is a side view of a bearing in which the arcuate pieces are made up of gap-type arcuate pieces and closed-type arcuate pieces. [Figure 2] FIG. 2(a) is a detailed view of part A in FIG. 1(a), and FIG. 2(b) is an enlarged view of the positioning plate portion. [Figure 3] Fig. 3(a) shows an enlarged partial cross-sectional view of the anchor member. Fig. 3(b) shows a case where two bottom arc pieces (slotted arc pieces) on the left and right are fitted to the anchor member, and Fig. 3(b) shows a case where one arc piece (closed arc piece) is fitted to the anchor member. [Figure 4] 4(a) and 4(b) are drawings showing the shapes and configurations of various arc pieces. Fig. 4(a) is a drawing explaining the configuration of a closed-type arc piece, Fig. 4(b) is a drawing explaining the configuration of a gap-type arc piece, Fig. 4(c) is an explanatory diagram of the arrangement of the grooves in the bottom arc piece that fit into the anchor member, and Fig. 4(d) is an explanatory diagram of the notches provided in the side end of the closed-type arc piece that contacts the lower edge of the positioning plate. [Figure 5] 1A and 1B are schematic diagrams illustrating the state of wear of a bearing and an explanatory diagram of a bearing regeneration method. [Figure 6] FIG. 2 is an explanatory diagram of a bearing regeneration method. DETAILED DESCRIPTION OF THE INVENTION

[0023] An embodiment of the present invention will now be described. An example of a bearing according to the present invention is shown in FIG. 1. FIG. 1 shows a front view and a side view of the bearing. As shown in the side view, the bearing is divided into upper and lower halves by a horizontal axis (HA). The bearing according to the present invention is a barrel-type bearing in which an arc-shaped piece is held on the inner circumferential surface of a cylindrical shell that supports a ship's propulsion shaft. As shown in FIG. 1, the arc-shaped piece is held on the inner circumferential surface of a shell 11 that has an axially long main body 110 and a flange 111 provided on its end face. In this example, the flange side of the bearing 10 faces the stern. The bearing 10 includes a pair of positioning plates 12 fixed to the inner circumferential surface of the cylindrical shell 11 that supports the ship's propulsion shaft, facing each other on the horizontal axis of the shell 11; an anchor member 13 fixed to the lowest point Pb of the shell; and an arc-shaped piece 15. The arcuate piece 15 comprises a bottom arcuate piece 15b that fits into the anchor member 13, an upper arcuate piece disposed on the upper portion of the positioning plate 12, and a lower arcuate piece disposed on the lower portion. Here, the horizontal axis is an axis perpendicular to the center of gravity of the propeller shaft in the cross section of the shell 11. Note that Fig. 1(a) shows a bearing consisting only of gap-type arcuate pieces, as described below, while Fig. 1(b) shows a side view of a bearing in which the upper arcuate piece is a gap-type arcuate piece and the lower arcuate piece is a closed-type arcuate piece. While the bearing 10 in this example has a flange 111 as described above, there are also bearings without the flange 111. Furthermore, the mounting direction of the bearing may be reversed from that of the bearing 10 in this example, with the flange side facing the bow.

[0024] As shown in FIG. 2, the positioning plate 12 is comprised of an upper plate 121 and a lower plate 122 that are interlocked to form an integrated band-like body. The upper plate 121 has a shell-fixing means, and in this example, is screwed to the shell 11. The upper plate 121 and the lower plate 122 have an interlocking surface 123, and the lower plate 122 is held on the inner peripheral surface of the shell 11 via the upper plate 121 to prevent detachment or loosening. The lower plate 122 can be pulled out from the bearing 10 in which the positioning plate 12 and the arc piece 15 are disposed with a predetermined pull-out force. Considering functionality and workability, the upper plate 121 and the lower plate 122 preferably have a tapered interlocking surface 123 that becomes thicker (wider) toward the stern, as shown in FIG. 2(b). The lower plate 122 can be pulled out with a pull-out force of 0.1 to 20.0 tons. This allows bearings to be remanufactured easily and quickly using the bearing remanufacturing method described below. Note that the structure of the mating surface 123 of the positioning plate 12 is not limited to this example and may be of other types. For example, it may be a type in which a wedge is driven between the upper and lower plates to secure them together.

[0025] As shown in FIG. 1 or 3, the anchor member 13 is positioned at the lowest point P b The anchor member 13 is provided in a portion of the shell 11 and is fixed so as to extend in the axial direction of the shell 11. In this example, the anchor member 13 is screwed to the shell 11. The anchor member 13 has the function of fixing the bottom arc piece 15b in a predetermined position. The arc piece 15 is arranged on the inner peripheral surface of the shell based on the bottom arc piece 15b fitted into the anchor member 13. This makes it possible to easily and quickly assemble the arc piece 15. Note that although the anchor member 13 in this example is strip-shaped, it may also be a rod-shaped anchor member.

[0026] It is preferable that the surface pressure acting on the bottom arcuate piece 15b be uniform. To achieve this, the groove 155 of the bottom arcuate piece 15b that fits into the anchor member 13 should be short (FIGS. 1 and 4). It is also preferable that the groove 155 of the bottom arcuate piece 15b not be present at the lowest point Pb of the shell on the stern side of the bearing 10, which is subject to high loads. To ensure uniform surface pressure and a predetermined fitting length, the length of the anchor member 13 should be 50% to 75% of the length of the bottom arcuate piece 15b (the length of the shell 11). It is also preferable that the anchor member 13 be positioned so that the bottom arcuate piece 15b is inserted and fitted into the bearing 10 from the stern side. While the anchor member 13 in this example is configured to fit into the groove 155 of the bottom arcuate piece 15b, the bottom arcuate piece 15b may have a ridge portion, and the anchor member 13 may have a groove that fits into the ridge portion.

[0027] The arc pieces 15 have a width with a predetermined arc length or chord length on the inner peripheral surface of the shell 11, and a length extending in the axial direction of the shell 11. Depending on their shape, the arc pieces 15 are classified as gap-type arc pieces 15g and closed-type arc pieces 15p, as shown in Figure 4. The bearing 10 shown in Figure 1(a) is an example in which the inner peripheral surface of the shell 11 is formed by gap-type arc pieces 15g. Figure 1(b) is an example in which the upper side of the inner peripheral surface of the shell 11 is formed by gap-type arc pieces 15g and the lower side is formed by closed-type arc pieces 15p.

[0028] Shell 11's lowest point P B A bottom arcuate piece 15b is provided in the bottom arcuate portion. The bottom arcuate piece 15b can be either a gap type (arc piece 15gb) or a closed type (arc piece 15pb). As shown in FIG. 3, two bottom arcuate pieces 15b (15pb) are symmetrically arranged on the anchor member 13 (FIG. 3(a)), or one bottom arcuate piece 15b (15pb) is arranged (FIG. 3(b)). For this reason, as shown in FIG. 4(c), the bottom arcuate piece 15b may have a groove 155 that fits into the anchor member 13 at its bottom edge or bottom center. In the bottom arcuate piece 15b having a non-through groove 155 at its bottom edge, as in this example, there is a left arcuate piece 15bl and a right arcuate piece 15br.

[0029] It is preferable that the arcuate piece 15gm or arcuate piece 15pm (Figs. 1 and 2) that contacts the positioning plate 12 is ground against the positioning plate 12. This allows the arcuate piece 15 disposed on the inner peripheral surface of the shell 11 to be held against the shell's inner peripheral surface with a predetermined holding force while being pressed against each other. In the present bearing 10, the positioning plate 12 is made up of an upper plate 121 and a lower plate 122, so the arcuate piece 15 disposed on the upper side of the inner peripheral surface of the shell 11 is ground against the upper plate 121, and the arcuate piece 15 disposed on the lower side of the inner peripheral surface of the shell 11 is ground against the lower plate 122. Note that grounding refers to "hand finishing work to create a highly accurate flat surface. The surface is ground against a grinding table and then finished by scraping with a scraper (Kojien)." This processing method is also referred to as "precision surface finishing by burnishing, precision surface finishing; mating by rubbing together (Weblio English-Japanese Dictionary, Japanese-English Dictionary: https: / / ejje.weblio.jp / content / %E6%93%A6%E3%82%8A%E5%90%88%E3%82%8F%E3%81%9B)." When the arc-shaped piece 15 that contacts the positioning plate 12 is a sealed arc-shaped piece 15pm, it is preferable to provide a notch 156 in the side edge that contacts the positioning plate 12, as shown in FIG. 4(d). This notch 156 can prevent the end surface of the sliding layer 153 from lifting up, thereby suppressing stress concentration and wear of the sliding layer 153.

[0030] As shown in Fig. 4, the arc piece 15 preferably has a three-layer structure consisting of a sliding layer 153 having excellent wear resistance and heat resistance, an intermediate layer 152 made of an elastic material, and a base 151. The base 151 can be made of metal or resin. For the metal base 151, a copper alloy can be used, which has good machinability and excellent corrosion resistance. For the resin base 151, a fiber-reinforced thermosetting resin, for example, a carbon fiber-reinforced phenolic resin, can be used.

[0031] The intermediate layer 152 is preferably an elastic material with a hardness (Shore A) of 50° to 95°. For example, nitrile rubber (NBR) with a hardness (Shore A) of 50° to 95° can be used. When the intermediate layer is made of rubber, the three-layer structure is preferably formed by vulcanization bonding. This allows for the formation of a strong bonded structure. Such an intermediate layer 152 can equalize the load from the propeller shaft, suppress heat generation on the sliding surface of the sliding layer 153 of the propeller shaft, and improve the wear resistance and durability of the arc-shaped piece 15. Furthermore, when the closed arc-shaped piece 15p is disposed below the inner circumferential surface of the shell 11, the elastic deformation of the intermediate layer 152 is limited to a direction perpendicular to the rotational axis of the propeller shaft. Therefore, shear deformation does not occur at the joint surface between the sliding layer 153 and the intermediate layer 152, and deterioration of the adhesion portion between the sliding layer 153 and the intermediate layer 152 can be suppressed.

[0032] From the viewpoint of low friction, wear resistance, and heat resistance, the sliding layer 153 is preferably made of a synthetic polymer compound containing fluorine atoms (F) in the molecule. For example, fluororesins such as tetrafluoroethylene (PTFE) resin, tetrafluoroethylene-hexafluoropropylene copolymer (FEP) resin, and tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA) resin can be used. Alternatively, polyamide resin or phenolic resin can be used.

[0033] The above describes a bearing according to the present invention. In this bearing, the upper arcuate piece is formed from a gap-type arcuate piece, while the lower arcuate piece can be formed from either a gap-type arcuate piece or a sealed arcuate piece. A configuration in which the lower arcuate piece is a gap-type arcuate piece is adopted when bearing cooling is important, while a configuration in which the lower arcuate piece is a sealed arcuate piece is adopted when load is important. Furthermore, the upper arcuate piece of the bearing is preferably formed from an odd number of arcuate pieces, with the arcuate pieces arranged symmetrically on both sides of the arcuate piece at the top of the shell. By controlling the distance between the arcuate piece at the top of the shell and the bottom arcuate piece, the wear depth of the sliding surface of the bottom arcuate piece, which is the most heavily worn part of the bearing 10, can be measured and controlled, as described below, allowing for accurate measurement and control of the wear state of the bearing 10.

[0034] FIG. 5 is a schematic diagram showing the wear state of the bearing 10 during operation. Wear occurs on the lower arc-shaped piece of the bearing 10, particularly around the lowest point Pb on the stern side. The planar shape of the worn portion W is triangular, larger at the stern side and gradually decreasing toward the bow. The AA cross-sectional shape of the worn portion W has a smoothly downward sloping surface with the lowest point Pb as the valley, where the wear is most severe. As such, the wear of the bearing 10 is localized, with some portions barely worn. Therefore, when the worn portion W of the bearing 10 reaches a predetermined wear state, the bearing 10 can be refurbished by rearranging the worn arc-shaped piece with the unworn or barely worn arc-shaped piece. The bearing 10 can be refurbished with the propeller shaft inserted.

[0035] As described above, the wear state of the present bearing 10 is partial, with a smooth inclined surface. For this reason, rather than rearranging the arc pieces individually, it is preferable to rearrange them as a group (set) to ensure continuity of the wear surface. Rearranging the arc pieces to ensure continuity of the wear surface can prevent steps from occurring on the sliding surface of the bearing due to changes in the order of the arc pieces. This can also prevent abnormal wear of the arc pieces and vibration of the propeller shaft.

[0036] The rearrangement of the arc-shaped pieces 15 can be performed, for example, by dividing the lower arc-shaped pieces into two with respect to the bottom arc-shaped piece 15b, and rearranging each into a group. That is, the lower arc-shaped pieces can be rearranged so that the right side of the lowest point Pb of the shell 11 is one group and the left side of the lowest point Pb of the shell 11 is another group, with the axial directions (from stern to bow or longitudinal direction) reversed. In this case, the rearrangement is performed as shown by the dashed dotted line in Figure 5. The arc-shaped pieces 15 that are less worn are arranged closer to the lowest point Pb of the inner circumferential surface of the shell 11, and the arc-shaped pieces 15 that are more worn are arranged farther from the lowest point Pb. That is, the bottom arc-shaped piece 15b is rearranged to the position farthest from the lowest point Pb of the shell 11.

[0037] As shown in Figures 1 and 2, in the bearing for restoration, it is preferable to rearrange a group of arc pieces 15 (15gm, 15pm) excluding the arc piece 15 (15gm, 15pm) that contacts the lower edge of the positioning plate 12 (lower plate 122), taking into consideration that the arc piece 15 (15gm, 15pm) that contacts the lower edge of the positioning plate 12 (lower plate 122) is ground against the lower plate 122. In this case, after rearranging the group of arc pieces, the arc piece 15 that contacts the lower edge of the arc piece 15 that contacts the lower edge of the positioning plate 12 is arranged in the bottom arc piece position. In other words, the arc piece 15 that contacts the lower edge of the arc piece 15 that contacts the lower edge of the arc piece 15 that contacts the lower edge of the positioning plate 12 is arranged as an arc piece that can be replaced with the bottom arc piece 15b. This replaceable arc piece is used as a substitute arc piece for the bottom arc piece 15b.

[0038] Remanufactured bearings differ depending on the type of bottom arc piece 15b of the bearing. Remanufactured bearings 10A have a type in which the bottom arc piece 15b has a groove 155 on the bottom side edge as shown in Figure 6(a), while remanufactured bearings 10B have a type in which the bottom arc piece 15b has a groove 155 in the bottom center as shown in Figure 6(b). In remanufactured bearings 10A, the right-side substitute arc piece 15bl' has the same shape as the bottom arc piece 15bl but is arranged in the reversed front-to-back direction, while the left-side substitute arc piece 15br' has the same shape as the bottom arc piece 15br but is arranged in the reversed direction. In remanufactured bearings 10B, the left and right substitute arc pieces 15b' have the same shape as the bottom arc piece 15b but are arranged in the reversed direction. Note that the left and right sides of the bearing (10, 10A, or 10B) or arc piece 15 are defined relative to the vertical axis VA of the cross section of the shell 11. The vertical axis is the axis perpendicular to the horizontal axis and points in the opposite direction to the center of gravity of the propeller shaft, and the right side of the vertical axis is the right side of the shell cross section.

[0039] The bearing 10A to be remanufactured as shown in FIG. 6(a) is remanufactured as follows. First, the right-side substitute arcuate piece 15bl' to the bottom arcuate piece 15br constitute the right arcuate piece group 15R, and the left-side substitute arcuate piece 15br' to the bottom arcuate piece 15bl constitute the left arcuate piece group 15L. Next, the lower plate 122 is removed from the shell 11. The right arcuate piece group 15R is then removed as a group from the shell 11, the axial direction is reversed, and the group is reinstalled as is in the shell 11. Next, the left arcuate piece group 15L is removed as a group from the shell 11, the axial direction is reversed, and the group is reinstalled as is in the shell 11, rearranging the arcuate pieces. Note that the axial direction refers to the direction from the stern to the bow of the bearing.

[0040] The bearing 10B shown in FIG. 6(b) is remanufactured as follows. First, the right-side substitute arc piece 15b' to the bottom arc piece 15b constitute the right arc piece group 15R, and the left-side substitute arc piece 15b to the arc piece 15 tangent to the bottom arc piece 15b constitute the left arc piece group 15L. Alternatively, the right-side substitute arc piece 15b' to the arc piece tangent to the bottom arc piece 15b constitute the right arc piece group 15R, and the left-side substitute arc piece 15b' to the bottom arc piece 15b constitute the left arc piece group 15L. However, the bottom arc piece 15b can be included in either the right arc piece group 15R or the left arc piece group 15L, and this can be determined based on the condition of the worn portion W. Next, the lower plate 122 is pulled out of the shell 11. Then, the right arc-shaped piece group 15R is pulled out as a group from the shell 11, the axial direction is reversed, and the group is reinstalled as such in the shell 11. Then, the left arc-shaped piece group 15L is pulled out as a group from the shell 11, the axial direction is reversed, and the group is reinstalled as such in the shell 11, thereby rearranging the arc-shaped pieces. [Explanation of symbols]

[0041] 10 Bearings 11 Shell 110 Main Unit 111 flange 12 Positioning plate 121 Upper Plate 122 Lower Plate 123 mating surface 13 Anchor member 15. Arc piece 151 Foundation 152 Middle Class 153 Sliding Layer 154 Groove forming part 155 Groove 156 Notch

Claims

1. The device comprises a pair of positioning plates fixed to the inner peripheral surface of a cylindrical shell supporting a propulsion shaft of a ship on a horizontal axis of the shell in opposing relation to each other, an anchor member fixed to the lowest point Pb of the shell, and an arc piece, The arcuate piece includes a bottom arcuate piece that fits onto the anchor member, an upper arcuate piece that is disposed on the upper portion of the positioning plate, and a lower arcuate piece that is disposed on the lower portion of the positioning plate. Here, the horizontal axis refers to an axis perpendicular to the center of gravity of the propeller shaft in the cross section of the shell.

2. 2. The bearing according to claim 1, wherein the arcuate piece in contact with the lower edge of the positioning plate has a shape that is interchangeable with the bottom arcuate piece.

3. 3. A bearing according to claim 1, wherein the bottom arcuate piece has a groove formed in a central portion or a side edge portion of the bottom portion, the groove fitting with the anchor member.

4. The upper arcuate piece is pressed against and held by the upper inner peripheral surface of the shell via a positioning plate, 3. A bearing according to claim 1, wherein the lower arcuate piece is pressed against and held by the lower inner peripheral surface of the shell via the positioning plate and the bottom arcuate piece.

5. 3. A bearing according to claim 1 or 2, characterized in that the positioning plate is a strip-shaped body that is integrally formed by engaging an upper plate having a shell fixing means with a lower plate that is held against the inner peripheral surface of the shell via the upper plate.

6. 6. A bearing according to claim 5, wherein the lower plate can be pulled out of the shell with a predetermined pulling force in a state where all of the arc pieces are disposed on the inner peripheral surface of the shell.

7. 6. A bearing according to claim 5, wherein the upper plate is fitted to a circular arc piece in contact therewith, and the lower plate is fitted to a circular arc piece in contact therewith.

8. 3. A bearing according to claim 1, wherein the number of upper arcuate pieces is an odd number, including the arcuate piece at the top of the shell.

9. 3. A bearing according to claim 1, wherein the upper arcuate piece is a gap-type arcuate piece, and the lower arcuate piece is a gap-type arcuate piece or a closed arcuate piece.

10. The device comprises a pair of positioning plates fixed to the inner peripheral surface of a cylindrical shell supporting a propulsion shaft of a ship on a horizontal axis of the shell in opposing relation to each other, an anchor member fixed to the lowest point Pb of the shell, and an arc piece, a bearing reconditioning method, the arc-shaped piece including a bottom arc-shaped piece that fits onto the anchor member, an upper arc-shaped piece that is disposed on an upper portion of the positioning plate, and a lower arc-shaped piece that is disposed on a lower portion of the positioning plate, A bearing regeneration method in which, when the wear depth of the lowest point Pb portion of the worn portion W occurring on the stern side of the lower arc piece reaches a predetermined value, the arc piece is rearranged so that the less worn arc piece is arranged closer to the lowest point Pb on the inner surface of the shell, and the more worn arc piece is arranged farther from the lowest point Pb. Here, the horizontal axis refers to an axis perpendicular to the center of gravity of the propeller shaft in the cross section of the shell.

11. 11. The method for restoring a bearing according to claim 10, wherein the rearrangement of the arc pieces is carried out so as to ensure continuity of the wear cross section of the worn portion W.

12. The device comprises a pair of positioning plates fixed to the inner peripheral surface of a cylindrical shell supporting a propulsion shaft of a ship on a horizontal axis of the shell in opposing relation to each other, an anchor member fixed to the lowest point Pb of the shell, and an arc piece, the positioning plate is a band-shaped body in which an upper plate having a shell fixing means and a lower plate held on the inner peripheral surface of the shell via the upper plate are engaged with each other to form a single body; the arcuate piece includes a bottom arcuate piece that fits onto the anchor member, an upper arcuate piece that is disposed on an upper portion of the positioning plate, and a lower arcuate piece that is disposed on a lower portion of the positioning plate; The lower arc piece in contact with the lower edge of the arc piece in contact with the lower edge of the positioning plate is a substitute arc piece that can be replaced with the bottom arc piece. Here, the horizontal axis refers to an axis perpendicular to the center of gravity of the propeller shaft in the cross section of the shell.

13. 13. The bearing according to claim 12, wherein the right side substitute circular arc piece to the bottom circular arc piece are defined as a right circular arc piece group, and the left side substitute circular arc piece to the bottom circular arc piece are defined as a left circular arc piece group, First, pull out the lower plate from the shell, Next, the right group of arc-shaped pieces is pulled out from the shell as a group, the axial direction is reversed and they are reinstalled in the shell as a group, and the left group of arc-shaped pieces is pulled out from the shell as a group, the axial direction is reversed and they are reinstalled in the shell as a group, thereby rearranging the arc-shaped pieces. Here, the vertical axis refers to the axis that is opposite to the direction of the center of gravity of the propeller shaft, which is perpendicular to the horizontal axis, and the right side of the vertical axis is called the right side of the shell cross section.

14. In the bearing according to claim 12, the right circular arc piece group is from the substitute circular arc piece on the right side to the bottom circular arc piece, and the left circular arc piece group is from the substitute circular arc piece on the left side to the circular arc piece tangent to the bottom circular arc piece, or the right circular arc piece group is from the substitute circular arc piece on the right side to the circular arc piece tangent to the bottom circular arc piece, and the left circular arc piece group is from the substitute circular arc piece on the left side to the bottom circular arc piece, First, pull out the lower plate from the shell, Next, the right group of arc-shaped pieces is pulled out from the shell as a group, the axial direction is reversed and they are reinstalled in the shell as a group, and the left group of arc-shaped pieces is pulled out from the shell as a group, the axial direction is reversed and they are reinstalled in the shell as a group, thereby rearranging the arc-shaped pieces. Here, the vertical axis refers to the axis that is opposite to the direction of the center of gravity of the propeller shaft, which is perpendicular to the horizontal axis, and the right side of the vertical axis is called the right side of the shell cross section.

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