bearings

Abstract

To provide a bearing that, when automatically cleaned by spraying cleaning solution, prevents tank contents (organic matter, etc.) from remaining in the bearing, thereby reducing the frequency of disassembly and manual cleaning of the bearing. [Solution] The bearing (5) of the present invention is a bearing (5) provided in a stirring tank (2) that supports a stirring shaft (3) having stirring blades (3A), and comprises a bush (6) disposed in the bottom (2A) of the stirring tank (2) into which the lower end of the stirring shaft (3) is inserted. The bush (6) is fitted into a through hole (7A) formed in the center of a plate (7) that is attached to a leg portion (8) provided in the bottom (2A) of the stirring tank (2). A chamfer (6I) is formed on the upper edge of the opening (6D) into which the lower end of the stirring shaft (3) is inserted of the bush (6), and a first cleaning fluid permeable groove (G1) is formed on the side surface of the bush (6) extending from the upper surface (6J) to the lower surface (6K) of the bush (6).

Description

TECHNICAL FIELD

[0001] The present invention relates to a bearing that pivotally supports a stirring shaft having stirring blades in a large stirring tank used, for example, in the production of lactic acid bacterium beverages.

BACKGROUND ART

[0002] In the tanks as described above (for example, see Patent Document 1), cleaning operations are performed at a predetermined frequency from the viewpoint of hygiene. Such cleaning operations are performed by, for example, an automatic cleaning system as shown in Figure 1. In Figure 1, the automatic cleaning system denoted by reference numeral 1 is provided in the stirring tank 2, and the stirring tank 2 has a stirring shaft 3 with stirring blades 3A, a cleaning liquid spraying device 4, and a bearing 35. The lower end of the stirring shaft 3 is pivotally supported by the bearing 35 arranged near the bottom 2A inside the stirring tank 2. The bearing 35 includes a bush 36 into which the lower end portion of the stirring shaft 3 is inserted, a plate 37 into which the bush 36 is fitted, and legs 38 fixed to the tank bottom surface 2A to support the plate 37. Details of the bearing 35 will be described later with reference to Figure 2. The stirring shaft 3 is rotationally driven by a drive device 10 (such as a motor). The automatic cleaning system 1 sprays the cleaning liquid from the cleaning liquid spraying device 4 into the tank 2 (arrow A) to wash away contents such as lactic acid bacterium beverages remaining on the inner wall of the tank 2 (the liquid to be stirred in the stirring tank 2, which contains a large amount of organic matter). The cleaning liquid is supplied from the cleaning liquid supply source 11 to the cleaning liquid spraying device 4 via the cleaning liquid supply pipe 12. A supply pump 13 is interposed in the cleaning liquid supply pipe 12. After being sprayed, the cleaning liquid accumulated at the bottom of the tank 2 is recovered and stored in the cleaning liquid supply source 11 via the cleaning liquid recovery pipe 14. A cleaning liquid recovery pump 15 is interposed in the cleaning liquid recovery pipe 14.

[0003] The bearing 35 will be described with reference to Figure 2. A through-hole is formed in the bush 36 of the bearing 35, and the lower end of the stirring shaft 3 is inserted into the opening 36D of the through-hole. Although not clearly shown in Figure 2, the bush 36 has a bush body 36A (Figure 3) and a flange 36B (see Figure 3), and the flange 36B is located above the bush body 36A (towards the ceiling of the stirring tank 2 when the bush 36 is installed on the bearing 35) and has a larger diameter than the bush body 36A. Only the flange 36B is shown in Figure 2. The bush body 36A is fitted into a through hole (first through hole) formed in the center of the plate 37, and the flange 36B is in contact with the upper surface (37C) of the plate 37. The plate 37 is attached to the leg portion 38, which is fixed to the bottom surface 2A of the stirring tank 2. The leg portion 38 has a leg support column 38A that is on the tank bottom 2A side and supports the plate 37, and a plate-side fitting portion 38B that is located above the leg support column 38A, and the upper end of the plate-side fitting portion 38B is shown in Figure 2. The plate 37 has a central through hole (not shown; corresponding to the first through hole 7A shown in Figures 7 and 8), with through holes 37B formed on both sides at equidistant locations. The through holes 37B engage with the plate-side fitting portion 38B, thereby attaching the plate 37 to the leg portion 38.

[0004] As shown in Figure 3, the bush 36 consists of a bush body 36A, which is cylindrical overall, and a large-diameter flange 36B located above the bush body 36A (on the side facing the ceiling of the stirring tank when installed on the bearing). Two notches 36E are formed at points symmetrical to the center of the flange 36B (or bush 36). As shown in Figure 3, a flange remaining portion 36F is formed in the area below the notches 36E (in Figure 3), and the vertical dimension (thickness dimension) of the flange remaining portion 36F is smaller than that of the flange 36B. In other words, the notches 36E are not formed over the entire vertical area of ​​the flange 36B. Through holes 36C are formed in the flange 36B and the bush body 36A, and as shown in Figure 2, the lower end of the stirring shaft 3 is inserted into the opening 36D of the through hole 36C. The bush body 36A is fitted into a through hole for bush fitting formed in the center of the plate 37, and as shown in Figure 2, the flange 36B and the upper surface (37C) of the plate 37 come into contact and bear the load of the stirring shaft 3. In Figure 3, the two notches 36E formed in the flange 36B are used to rotate the bush 36 by engaging with a tool (not shown). In the prior art, the remaining flange portion 36F at the bottom of the notches 36E (towards the bottom of the tank 2) was considered essential for bearing the load of the stirring shaft 3 by contacting the upper surface of the plate 37, and therefore the remaining flange portion 36F was provided.

[0005] In Figure 3, in order to securely fit the bush 36 into the plate 37, a bent groove PG is formed below the bush body 36A (on the side of the bottom 2A of the stirring tank), communicating with the lower end surface 36K of the bush 36 (bush body 36A). Although not explicitly shown, the through-hole for bush fitting (the first through-hole: corresponding to the first through-hole 7A shown in Figures 7 and 8) has a projection formed on the bush body 36A that engages with the groove PG. When fitting the bush 36 to the plate 37, the projection on the plate side (not shown) is inserted into the groove PG of the bush body 36A and engages with it. As shown in Figure 3, the groove PG has a first region PG1 extending in the vertical direction (along the central axis direction of the bush 36), a second region PG2 extending in the circumferential direction of the bush body 36A, and a third region PG3 extending in the vertical direction. When the projection (not shown) on the plate 37 side is inserted into the first region PG1, the bush 36 is pushed into the plate 37 so that the projection moves within region PG1. When the projection reaches the second region PG2, the bush 36 is rotated to move the projection within the second region PG2. When the projection reaches region PG3, the bush 36 is pushed into the plate 37 to move the projection within region PG3. In this way, the bush 36 and the plate 37 engage in a manner similar to that of a key and keyway.

[0006] As shown in Figure 1, the bearing 35 is located at the bottom 2A of the stirring tank 2, making it far from the cleaning fluid spraying device 4 that sprays the cleaning fluid, and therefore difficult to clean. Also, as explained with reference to Figures 2 and 3, the bearing 35 is composed of three parts: a bush 36, a plate 37, and a leg 38, but there were parts that could not be cleaned by the cleaning fluid spraying device alone. The inventor conducted an experiment to confirm the cleaning effect on each of the components that make up the bearing 35: the bush 36, the plate 37, and the leg portion 38. Assuming that the contents of tank 2 were food or beverages, the experiment to confirm the cleaning effect was conducted under strict standards, and even the slightest amount of remaining dirt was judged as "dirt present." In confirming the cleaning effect, the components of bearing 35 were disassembled after cleaning.

[0007] As a result of the inventor's experiments, as shown in Figure 4, in bush 36, (1) The sliding surface (inner contact surface of the bearing) of the bush 36 and the stirring shaft 3, (2) Boundary between the remaining flange portion 36F and the flange notch 36E (flange 36B) (3) Grooves PG (especially region PG3) formed in the bush body 36A, However, it was identified as a place where organic matter (dirt) is likely to remain. In the leg portion 38, as shown in Figure 5, (4) Stepped portion 38C of the leg portion 38 arranged on the left and right (boundary between the leg support column 38A and the plate-side fitting portion 38B located above the leg support column 38A), However, areas where organic matter (dirt) tends to remain were identified. The areas where dirt tended to remain and where dirt that could not be completely cleaned existed are indicated by symbols (1) to (4) in Figures 4 and 5. In Figure 5, only one of the two legs 38, which are positioned on the left and right sides, is shown. Reference numeral 37 denotes a plate, and reference numeral 37B denotes a through hole formed in the plate.

[0008] As described above, since there are parts of the bearing 35 that cannot be cleaned by the automatic cleaning system 1, in the case of a stirring tank 2 used in the food industry, where hygiene standards are particularly strict, after cleaning with the automatic cleaning system 1, an operator enters the inside of the tank 2 to disassemble and manually clean the bearing 35. However, the process of workers entering the tank 2 to disassemble and hand-clean the bearing 35 required them to ascend and descend slippery steps from the tank opening, placing a significant physical burden on the workers. For this reason, there has long been a desire to reduce the frequency of disassembling and hand-cleaning the bearing 35, but no technology has yet been proposed to meet this demand.

[0009] Other conventional technologies include a technique in which grooves are formed on the outer circumference of the bush for flowing slurry (see Patent Document 2), but this is a technique for suppressing shaft wear and is not intended to prevent tank contents (organic matter, etc.) from remaining on the bearing by spraying cleaning fluid with an automatic cleaning system, nor is it intended to reduce the frequency of disassembling and manually cleaning the bearing. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2020-54965 [Patent Document 2] Japanese Patent Publication No. 2022-64730 [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] This invention was proposed in view of the problems of the prior art described above, and aims to provide a bearing that, after spraying cleaning fluid in an automatic cleaning system, does not leave any tank contents (organic matter, etc.) on the bearing, thereby reducing the frequency of disassembly and manual cleaning of the bearing. Furthermore, the present invention aims to provide a test method that can reliably determine whether or not fluid, such as tank contents, remains in a bearing. Furthermore, the present invention aims to provide a test method that can determine whether a second cleaning fluid permeable groove is necessary to increase the amount of cleaning fluid permeate at the boundary between the outer circumferential surface of the leg and the inner circumferential surface of the second through hole, and at the stepped portion (shoulder portion) of the leg located at the said boundary. [Means for solving the problem]

[0012] The bearing (5) of the present invention is In a bearing (5) provided in a stirring tank (2) that supports a rotating shaft (3: stirring shaft) having a stirring blade (3A), The stirring tank (2) is equipped with a bush (6) located at the bottom (2A) and into which the lower end of the rotating shaft (3) is inserted. The bush (6) is fitted into a through hole (7A) formed in the center of a plate (7) which is attached to a leg (8) provided at the bottom (2A) of the stirring tank (2). A chamfer (6I) is formed on the upper edge of the opening (6D) into which the lower end of the rotating shaft (3) of the bush (6) is inserted. The bush (6) is characterized in that a first cleaning fluid permeable groove (G1) is formed on its side surface, extending continuously from the upper surface (6J) to the lower surface (6K) of the bush (6). In the present invention, The first cleaning fluid permeable groove (G1) has a first region (G1A) extending vertically from the lower surface (6K) of the bush (6), a second region (G1B) communicating with the first region (G1A) and extending circumferentially to the bush (6), and a third region (G1C) communicating with the second region (G1B) and extending vertically to the bush (6) and reaching the upper surface (6J) of the bush (6). The bush (6) is provided with a flange (6B), and the outer diameter of the flange (6B) is larger than the inner diameter of the through hole (7A). It is preferable that the region (6E) of the flange (6B) where the third region (G1C) of the first cleaning liquid permeation groove (G1) extends is cut out.

[0013] The bearing (5) of the present invention is A bearing (5) that is provided in the stirring tank (2) and supports the rotating shaft (3: stirring shaft) having the stirring blade (3A), A rectangular plate (7) that accommodates the bush (6) into which the lower end of the rotating shaft (3) is inserted is provided on the bottom (2A) of the stirring tank (2), The plate (7) is formed with a first through hole (7A) for accommodating the bush (6), and a second through hole (7B) into which the leg portion (8) protruding from the bottom (2A) in the stirring tank (2) is inserted, A plurality of (for example, four for a single second through hole 7B) second cleaning liquid permeation grooves (G2) communicating with the second through hole (7B) are formed on the upper surface (7C) and the lower surface (7D) of the plate (7). In the present invention, the second cleaning liquid permeation groove (G2) preferably extends at an inclination angle of 30° to 60° with respect to an imaginary line that passes through the center point (7BO) of the second through hole (7B) and is parallel to the long side (7PL) or the short side (7PS) of the plate (7). Here, the second cleaning liquid permeation groove (G2) preferably has a depth dimension of 0.5 mm ± 20% and a width dimension of 4 mm ± 20%.

[0014] The bearing (5) of the present invention is A bearing (5) that is provided in the stirring tank (2) and supports the rotating shaft (3: stirring shaft) having the stirring blade (3A), It is arranged on the bottom (2A) in the stirring tank (2) and includes a bush (6) into which the lower end of the rotating shaft (3) is inserted, The bush (6) is fitted into a through hole (7A) formed in the center of a plate (7) attached to a leg portion (8) provided on the bottom (2A) of the stirring tank (2), A chamfer (6I) is formed on the upper edge of the opening (6D) into which the lower end of the rotating shaft (3) of the bush (6) is inserted. A first cleaning fluid permeable groove (G1) is formed on the side surface of the bush (6), extending continuously from the upper surface (6J) to the lower surface (6K) of the bush (6). The plate (7) has a first through-hole (7A) for housing the bush (6) and a second through-hole (7B) into which the leg portion (8) protruding from the bottom (2A) of the stirring tank (2) is inserted. The plate (7) is characterized in that a plurality of second cleaning fluid permeable grooves (G2) are formed on the upper surface (7C) and lower surface (7D) of the plate (7), which communicate with the second through hole (7B). In the present invention, The first cleaning fluid permeable groove (G1) has a first region (G1A) extending vertically from the lower surface (6K) of the bush (6), a second region (G1B) communicating with the first region (G1A) and extending circumferentially to the bush (6), and a third region (G1C) communicating with the second region (G1B) and extending vertically to the bush (6) and reaching the upper surface (6J) of the bush (6). The bush (6) is provided with a flange (6B), and the outer diameter of the flange (6B) is larger than the inner diameter of the first through hole (7A). The region of the flange (6B) to which the third region (G1C) of the first cleaning fluid permeable groove (G1) extends is cut out. Preferably, the second cleaning fluid permeable groove (G2) extends with an inclination angle of 30° to 60° with respect to a virtual line passing through the center point of the second through hole (7B) and parallel to the long side (7PL) or short side (7PS) of the plate (7). Here, the second cleaning fluid permeable groove (G2) preferably has a depth dimension of 0.5 mm ± 20% and a width dimension of 4 mm ± 20%.

[0015] In a test method for confirming the cleaning performance of the bearing (5: bearing according to claims 1 to 6) (the ability to clean the amount of remaining organic matter to a predetermined amount or less using an automatic cleaning system (1) without disassembly and cleaning), The steps include applying a fluid having a viscosity of a predetermined value or higher (a viscosity greater than or equal to the viscosity of the liquid stirred in the stirring tank 2: for example, 200 mPa·S) to the bearing (5), A step of cleaning the bearing (5) to which the fluid has been applied using an automatic cleaning system (1: for example, a pipe cleaning system: CIP), A step of inspecting the remaining amount of fluid having a viscosity of the predetermined value or higher, The system is characterized by having a step to determine whether the remaining amount of organic matter is below a certain threshold (for example, whether the chemical oxygen demand (COD value), which is an indicator of the amount of organic matter in water, is 0.5 ppm or less).

[0016] In a test method for confirming the cleaning performance of the bearing (5: bearing according to claims 3 to 6) (the ability to clean the amount of remaining organic matter to a predetermined amount or less using an automatic cleaning system (1) without disassembly and cleaning), A step of injecting a stained liquid into one of the second cleaning liquid permeable grooves (G2) that communicate with the second through hole (7B) formed in the plate (7), The process includes disassembling the bearing (5) after injecting the stained liquid, and inspecting the degree of staining in areas where organic matter is deemed likely to remain. For each of the plurality of bearings (5) whose second cleaning fluid permeable groove (G2) extends in a different direction, the steps of injecting the stained liquid and inspecting the degree of staining are performed, and the degree of staining in each bearing (5) is compared in the areas where it is previously determined that there is a high possibility of organic matter remaining. The present invention is characterized by including a step of determining that a bearing (5) with a wide stained area in a location previously identified as having a high probability of residual organic matter is a bearing (5) with high cleaning performance due to high permeability of the cleaning solution in the second cleaning solution permeation groove (G2) during automatic cleaning. [Effects of the Invention]

[0017] According to the bearing (5) of the present invention having the above configuration, a first cleaning fluid permeable groove (G1) is formed on the side surface of the bush (6) and extends continuously from the upper surface (6J) to the lower surface (6K) of the bush (6). When cleaning fluid is sprayed by the automatic cleaning system (1), the sprayed cleaning fluid flows from the upper surface (6J) of the bush (6) through the cleaning fluid permeable groove (G1) to the lower surface (6K) of the bush (6). As will be described later, organic matter tends to remain in the first cleaning fluid permeable groove (G1) formed on the side surface of the bush (6). However, since the sprayed cleaning fluid flows from the upper surface (6J) of the bush (6) through the first cleaning fluid permeable groove (G1) to the lower surface (6K) of the bush (6), the organic matter present in the first cleaning fluid permeable groove (G1) is removed by the cleaning fluid flowing through the first cleaning fluid permeable groove (G1). Furthermore, in the present invention, a chamfer (6I) is formed on the upper edge of the opening (6D) into which the lower end of the rotating shaft (3: stirring shaft) of the bush (6) is inserted. This makes it easier for the sprayed cleaning liquid to penetrate the sliding surface between the inner circumferential surface of the bush (6) and the outer circumferential surface of the rotating shaft (3) (the boundary between the bush 6 and the rotating shaft 3), allowing any remaining organic matter in the sliding part to be washed away.

[0018] Here, the first cleaning fluid permeable groove (G1) has a first region (G1A) extending vertically from the lower surface (6K) of the bush (6), a second region (G1B) communicating with the first region (G1A) and extending circumferentially to the bush (6), and a third region (G1C) communicating with the second region (G1B) and extending vertically to the bush (6) and reaching the upper surface (6J) of the bush (6). If the region of the flange (6B) to which the third region (G1C) of the first cleaning fluid permeable groove (G1) extends is cut out, the cleaning fluid sprayed from above the stirring tank (2) by the automatic cleaning system (1) flows smoothly through the first cleaning fluid permeable groove (G1) from the upper surface (6J) of the bush (6) to the lower surface (6K) of the bush (6). Therefore, even if organic matter remains in the first cleaning liquid permeable groove (G1) of the bush (6) within the stirring tank (2), it is reliably removed by the cleaning liquid sprayed during the cleaning operation passing through the first cleaning liquid permeable groove (G1). In addition, since the flange residue portion (36F) in the conventional technology is removed, any organic matter remaining at the boundary between the flange residue portion (36F) and the notch (38E) or in the dump in the conventional technology is removed by the flow of the cleaning solution according to the present invention.

[0019] Furthermore, according to the present invention, since the upper surface (7C) and lower surface (7D) of the plate (7) have a plurality of second cleaning liquid permeable grooves (G2) that communicate with the second through hole (7B) (for example, four grooves for a single second through hole 7B), the sprayed cleaning liquid is supplied to the boundary between the outer circumferential surface of the leg portion (8: plate-side fitting portion 8B) and the inner circumferential surface of the second through hole (7B) via the second cleaning liquid permeable grooves (G2). The cleaning liquid that has passed through the boundary between the outer circumferential surface of the leg portion (8) and the inner circumferential surface of the second through hole (7B) reaches the area of ​​the leg portion (8) below the plate (7) (towards the bottom 2A side of the stirring tank 2) and flows along the outer circumferential surface of the leg portion (8: leg support 8A). Therefore, even if organic matter remains at the boundary between the outer surface of the leg portion (8) and the inner surface of the second through hole (7B), or at the stepped portion (8C: shoulder portion) of the leg portion (8) located at the boundary, it will be removed by the permeating cleaning solution. Furthermore, a sufficient amount of cleaning solution will flow through the area of ​​the leg portion (8) below the plate (7).

[0020] According to the inventor's experiments, when the second cleaning fluid permeable groove (G2) extends with an inclination angle of 30° to 60° with respect to a virtual line passing through the center point (7BO) of the second through hole (7B) and parallel to the long side (7PL) or short side (7PS) of the plate (7), it was confirmed that the amount of cleaning fluid permeating at the boundary between the outer circumferential surface of the leg portion (8: plate-side fitting portion 8B) and the inner circumferential surface of the second through hole (7B), and at the stepped portion (8C: shoulder portion) of the leg portion (8) located at the said boundary, increases compared to when the second cleaning fluid permeable groove (G2) extends in other directions. Furthermore, as the amount of cleaning solution that permeates increases, even if organic matter remains at the boundary between the outer surface of the leg portion (8: plate-side fitting portion 8B) and the inner surface of the second through hole (7B), or at the stepped portion (8C: shoulder portion) of the leg portion (8) located at the said boundary, it will be reliably removed by the cleaning solution.

[0021] In the test method for confirming the cleaning performance of the bearing (5: bearing according to claims 1 to 6) of the present invention, a fluid having a viscosity of a predetermined value or higher (a viscosity higher than the viscosity of the liquid stirred in the stirring tank 2: for example, 200 mPa·S) is applied to the bearing (5), and the remaining amount of the fluid having a viscosity of a predetermined value or higher is inspected. The fluid having a viscosity of a predetermined value or higher has a higher viscosity than the fluids handled in actual manufacturing equipment (for example, lactic acid bacteria beverages), and if it adheres to the surface of the bearing (5), it is difficult to remove. Therefore, if no dirt remains (clears the test) in the test using such fluid, there is no risk of beverages or the like remaining on the bearing (5) after automatic cleaning in the actual machine (actual stirring tank 2). Furthermore, in the test method of the present invention for confirming the cleaning performance of the bearing (5: bearing according to claims 3 to 6), it is possible to determine the second cleaning fluid permeable groove (G2) so that the permeability of the cleaning fluid in the second cleaning fluid permeable groove (G2) is increased. This contributes to designing a second cleaning fluid permeable groove (G2) that increases the amount of cleaning fluid permeation at the boundary between the outer circumferential surface of the leg portion (8) and the inner circumferential surface of the second through hole (7B), and at the stepped portion (8C: shoulder portion) of the leg portion (8) located at the boundary. [Brief explanation of the drawing]

[0022] [Figure 1] This is an explanatory diagram showing an example of a stirring tank to which the present invention is applied. [Figure 2] This is an explanatory diagram of the bearing for the stirring shaft. [Figure 3] This is an explanatory diagram of a bearing bush in conventional technology. [Figure 4] This is an explanatory diagram showing areas in bushes where organic matter tends to remain in conventional technology. [Figure 5] This is an explanatory diagram showing areas in the legs where organic matter tends to remain in conventional technology. [Figure 6] This is an explanatory diagram of a bush in an embodiment of the present invention. [Figure 7] This is an explanatory plan view of a plate in an embodiment of the present invention. [Figure 8] This is a front cross-sectional view illustrating an embodiment of the present invention, and is a cross-sectional view taken along the line A8-A8 in Figure 7. [Figure 9] This is a partial cross-sectional diagram of section E9 in Figure 8. [Figure 10] This is an explanatory diagram showing the direction in which the second cleaning fluid permeable groove extends. [Figure 11] This flowchart shows the procedure for a test to confirm the cleaning performance of the bearing according to the illustrated embodiment. [Figure 12] This flowchart shows the procedure for a test to confirm the permeability of the cleaning fluid in the second cleaning fluid permeability groove of the bearing according to the illustrated embodiment. [Modes for carrying out the invention]

[0023] The embodiments of the present invention will be described below, primarily with reference to Figures 6 to 12. The bearing and its components, the bush, plate, and legs, according to the illustrated embodiment, have different configurations from the bush 36, plate 37, and legs 38 of the conventional bearing 35 described in Figures 1 to 5, and are therefore indicated by different reference numerals than those used in Figures 1 to 5. The equipment and components of the prior art shown in Figures 1 to 5, which have the same configuration and effects as those in the illustrated embodiments (for example, the automatic cleaning system 1, the stirring tank 2, the stirring shaft 3, the cleaning liquid spraying device 4, etc.), will be described using the same reference numerals in the embodiments shown in Figures 6 to 12.

[0024] Referring to Figure 6, the bush 6 used in the bearing 5 according to the illustrated embodiment will now be described. Similar to the conventional bush 36 described in Figure 3, the bush 6 is located at the bottom 2A (Figure 1) of the stirring tank 2, and the bush body 6A and flange 6B are integrated into one structure. The bush body 6A is cylindrical overall. The flange 6B is located above the bush body 6A (on the ceiling side of the stirring tank 2 when installed in the bearing 5: see Figure 1) and has a larger diameter than the bush body 6A. A through hole 6C is formed in the bush 6 (or the bush body 6A and flange 6B), and the lower end of the stirring shaft 3 is inserted into the through hole 6C (opening 6D) (see Figure 2). As will be described later with reference to Figures 7 and 8, the bush body 6A is fitted into the through hole 7A (first through hole) formed in the center of the plate 7 (Figures 7 and 8), and the flange 6B abuts against the upper surface of the plate 7 (7C: see Figure 8) to bear the load of the stirring shaft 3. For this reason, the outer diameter of the flange 6B is set to be larger than the inner diameter of the through hole 7A in the plate 7. Furthermore, notches 6E are formed at two points symmetrically with respect to the center of the flange 6B. Unlike the conventional technology, the notches 6E are formed along the entire height of the flange 6B. The flange remaining portion 36F (Figure 3) found in the conventional technology does not exist. Experiments by the inventors have confirmed that even without the flange remaining portion 36F found in the conventional technology, the flange 6B and plate 7 can adequately support the load on the stirring shaft 3. A chamfer 6I is formed on the upper edge of the opening 6D into which the lower end of the stirring shaft 3 of the bush 6 (flange 6B) is inserted.

[0025] A first cleaning fluid permeable groove G1 is formed on the side surface of the bush 6, extending from the upper surface 6J to the lower surface 6K of the bush 6. The first cleaning fluid permeable groove G1 has a different configuration from the groove PG in the conventional technology (Figure 3). The first cleaning fluid permeable groove G1 has a first region G1A extending vertically from the lower surface 6K of the bush 6 (bush body 6A), a second region G1B communicating with the first region G1A and extending circumferentially to the bush 6 (bush body 6A), and a third region G1C communicating with the second region G1B, extending vertically to the bush 6 (bush body 6A and flange 6B), passing through a notch 6E formed in the flange 6B, and reaching (communicating with) the upper surface 6J of the flange 6B. Here, the region of the flange 6B to which the third region G1C of the first cleaning fluid permeable groove G1 extends is notched (the location of the notch 6E). The through-hole 7A (first through-hole) formed in the plate 7 (Figures 7 and 8) for bush fitting has a plate-side projection (not shown) corresponding to the first cleaning fluid permeable groove G1 described above. When the bush 6 is fitted into the plate 7, this plate-side projection engages with the groove G1 of the bush 6. This engagement is the same for the conventional fitting of bush 36 and plate 37.

[0026] In the bearing 5 including the bush 6 shown in Figure 6, the cleaning liquid sprayed from the cleaning liquid spraying device 4 above the stirring tank 2 by the automatic cleaning system 1 (Figure 1) smoothly permeates through the first cleaning liquid permeation groove G1 from the upper surface 6J of the bush 6 to the lower surface 6K of the bush 6, and flows from the bush body 6A through the notch 6E of the flange 6B to the third region G1C, the second region G1B, and the first region G1A. Therefore, the first cleaning liquid permeation groove G1 is continuous from the upper surface 6J to the lower surface 6K, and even if organic matter remains, the cleaning liquid sprayed from the automatic cleaning system 1 smoothly permeates and flows down, so any remaining organic matter is reliably cleaned and removed. In the illustrated embodiment, the first cleaning fluid permeable groove G1 is provided in only one location on the bush 6. For example, as shown in Figure 6, the first cleaning fluid permeable groove G1 is provided only on the front surface of the bush 6, and not on the back surface in Figure 6. However, it is also possible to provide the first cleaning fluid permeable groove G1 on both the front and back surfaces. In the bush 6 according to the illustrated embodiment, the flange remaining portion 36F (Figure 3) has been removed, so there is no boundary between the flange remaining portion 36F and the notch 36E as in the prior art, and therefore no organic matter remains there. Furthermore, in the bush 6 according to the illustrated embodiment, a chamfer 6I is formed on the upper edge of the opening 6D into which the lower end of the stirring shaft 3 is inserted. This chamfer 6I allows the sprayed cleaning liquid to easily penetrate the sliding surface between the inner surface of the bush 6 and the outer surface of the stirring shaft 3 (the boundary between the bush 6 and the stirring shaft 3), thereby cleaning any remaining organic matter in the sliding surface. In the inventor's experiments, when using the bush 6 according to the illustrated embodiment, no organic matter remained after automatic cleaning. As a result, the number of times disassembly and manual cleaning were required was significantly reduced compared to the conventional technology.

[0027] Next, with reference to Figures 7 to 10, the plate 7 used in the illustrated embodiment will be described. As explained in Figures 1 and 2, the plate 7 is attached to the legs 8 provided on the bottom 2A of the stirring tank 2. In Figures 7 and 8, a through hole 7A (first through hole) is formed in the center of the plate 7, and the bush body 6A (Figure 5) is fitted into the first through hole 7A. The flange 6B abuts against the upper surface 7C of the plate 7 and bears the load of the stirring shaft 3 (see Figure 1). The plate 7 has a first through-hole 7A for housing the bush 6 and a second through-hole 7B into which the leg portion 8 protruding from the bottom 2A of the stirring tank 2 is inserted. As shown in Figure 8, the leg portion 8 has a leg support column 8A and a plate-side fitting portion 8B. The leg support column 8A is located on the tank bottom 2A side and serves to support the plate 7. The plate-side fitting portion 8B is located above the leg support column 8A. Here, the plate 7 is attached to the leg portion 8 by fitting the plate-side fitting portion 8B of the leg portion 8 into the second through-hole 7B of the plate 7. Figure 7 shows the upper end surface of the plate-side fitting portion 8B. In Figure 7, the boundary between the outer circumferential surface of the leg portion 8 (plate-side fitting portion 8B) and the inner circumferential surface of the second through-hole 7B of the plate 7 is represented by a single circle, and the cleaning fluid can permeate (flow through) this boundary.

[0028] In Figure 7, the upper surface 7C and lower surface 7D (Figure 8) of the plate 7 have multiple second cleaning fluid permeable grooves G2 (for example, four grooves in each of the second through holes 7B) that communicate with the second through holes 7B. To avoid complexity in the illustration, the second cleaning fluid permeable grooves G2 are not shown in Figure 8. In Figure 7, the second cleaning fluid permeable groove G2 preferably extends with an inclination angle of 30° to 60° with respect to a virtual line IL parallel to the long side 7PL of the plate 7 or a virtual line IS parallel to the short side 7PS of the plate 7, passing through the center point 7BO of the second through hole 7B. In the embodiment shown in Figure 7, it is set to 45°. A more detailed angle of the second cleaning fluid permeable groove G2 will be described later with reference to Figure 10. According to the inventor's experiments, the second cleaning fluid permeable groove G2 was preferably configured with a depth of 0.5 mm ± 20% and a width of 4 mm ± 20%.

[0029] In the illustrated embodiment, as shown in Figures 8 and 9, the boundary between the leg support column 8A and the plate-side fitting portion 8B in the leg portion 8 forms a stepped portion 8C, and the lower surface 7D of the plate 7 abuts against the stepped portion 8C. In the prior art, as explained with reference to Figure 5, organic matter (dirt) remained on the stepped portion 8C at the boundary between the leg portion 8 and the plate 7. Refer to Figures 7 to 9 to explain the flow of the cleaning fluid that reaches the upper surface 7C of plate 7. In Figure 9, such a flow of cleaning fluid is indicated by arrow A9. When the cleaning liquid sprayed from the cleaning liquid spraying device 4 (Figure 1) reaches the upper surface 7C of the plate 7, the cleaning liquid flows through the second cleaning liquid permeable groove G2 (Figure 7) over the boundary between the outer surface of the leg portion 8 and the inner surface of the second through hole 7B. The cleaning solution then passes through the boundary between the outer surface of the plate-side fitting portion 8B and the inner surface of the second through-hole 7B, flows along the stepped portion 8C which is the boundary between the plate-side fitting portion 8B and the leg support 8A, reaches the area of ​​the leg 8 below the plate 7 (towards the bottom 2A of the stirring tank 2), flows along the outer surface of the leg support 8A, and reaches the bottom 2A of the stirring tank 2 (Figure 1). Therefore, even if organic matter remains at the boundary between the outer surface of the plate-side fitting portion 8B and the inner surface of the second through-hole 7B, or at the boundary between the plate-side fitting portion 8B and the leg support 8A (stepped portion 8C), it is removed by the flow of the cleaning solution. In addition, sufficient cleaning solution flows to the area of ​​the leg 8 below the plate 7 (leg support 8A) to wash away any remaining organic matter.

[0030] Referring to Figure 10, the direction in which the second cleaning fluid permeable groove G2, which communicates with the second through-hole 7B of the plate 7, extends will be explained. As described above with reference to Figure 8, in the illustrated embodiment, four second cleaning fluid permeable grooves G2 are formed in one second through hole 7B, and these four second cleaning fluid permeable grooves G2 are each pair of symmetrical second cleaning fluid permeable grooves G2 extending as straight lines with respect to the center point 7BO of the through hole 7B. In Figure 10, the second cleaning fluid permeable grooves G2 that form straight lines are denoted by reference numerals G21 and G22. The above description is similar for each of the second cleaning fluid permeable grooves G2 that communicate with the two second through holes 7B. In Figure 10, a virtual line parallel to the long side 7PL of plate 7 (Figure 7) and passing through the center point 7BO of the second through hole 7B is indicated by the symbol IL, and a virtual line parallel to the short side 7PS of plate 7 (Figure 7) and passing through the center point 7BO of the second through hole 7B is indicated by the symbol IS. The inclination angle θ1L between the second cleaning fluid permeable groove G21 and the virtual line IL, and the inclination angle θ1S between the second cleaning fluid permeable groove G21 and the virtual line IS are set to 30° or more and 60° or less (30°~60°), with 45° being particularly preferred. Similarly, the inclination angle θ2L between the second cleaning fluid permeable groove G22 and the virtual line IL, and the inclination angle θ2S between the second cleaning fluid permeable groove G22 and the virtual line IS are also set to 30° to 60°, with 45° being particularly preferred.

[0031] According to the inventor's experiments (see Figure 12 and the tests described later), when the inclination angle θ1S between the second cleaning fluid permeable groove G21 and the virtual line IS, and the inclination angle θ2S between the second cleaning fluid permeable groove G22 and the virtual line IS are 30° to 60°, that is, when the inclination angle θ1L between the second cleaning fluid permeable groove G21 and the virtual line IL, and the inclination angle θ2L between the second cleaning fluid permeable groove G22 and the virtual line IL are 30° to 60°, the permeation performance of the cleaning fluid was better than when the inclination angles θ1S, θ2S, θ1L, and θ2L were less than 30° and when the inclination angles θ1S, θ2S, θ1L, and θ2L were greater than 60°. In particular, the permeability of the cleaning solution was good when the inclination angles θ1S, θ2S, θ1L, and θ2L were 45°. Furthermore, it was confirmed that when the inclination angles θ1S, θ2S, θ1L, and θ2L are between 30° and 60°, the amount of cleaning fluid flowing through the boundary between the outer surface of the leg portion 8 and the inner surface of the second through hole 7B, and the amount of cleaning fluid flowing through the stepped portion 8C (shoulder portion) of the leg portion 8 located at the boundary between the plate-side fitting portion 8B and the leg support column 8A, increases. As the amount of cleaning fluid flowing (permeation) increases, even if organic matter remains at the boundary between the outer surface of the leg portion 8 and the inner surface of the second through hole 7B, or at the stepped portion 8C of the leg portion 8 located at the boundary between the plate-side fitting portion 8B and the leg support column 8A, it will be reliably removed by the cleaning fluid. The inclination angles θ1S, θ2S, θ1L, and θ2L on the top surface 7C (front) and bottom surface 7D (back) of the plate may be the same or different. Furthermore, while the inclination angles θ1S, θ2S, θ1L, and θ2L on one of the surfaces (e.g., top surface 7C) are set to 30° to 60°, the inclination angles on the other surface (e.g., bottom surface 7D) can be set to less than 30° or greater than 60°.

[0032] Next, referring mainly to Figure 11, we will describe a test to confirm the cleanability of the bearing according to the illustrated embodiment (the ability to clean the amount of remaining organic matter to a predetermined value or less using the automatic cleaning system 1 without disassembly). In Figure 11, in step S1, a fluid for verification testing (dummy fluid) is applied to each component of the bearing 5 (bushing 6, plate 7, leg 8) (step of applying dummy fluid). The dummy fluid is a fluid having a viscosity of a predetermined value or higher, that is, a viscosity higher than or equal to the viscosity of the liquid being stirred in the stirring tank 2 (for example, 200 mPa·S). When applying the dummy fluid, it is applied to multiple locations, including areas where organic matter is likely to remain even after cleaning, as shown in Figures 4 and 5. Then, in step S2, the bearing 5, which has been coated with dummy liquid, is placed in the stirring tank 2.

[0033] In step S3, cleaning is performed by spraying cleaning solution with an automatic cleaning system 1 (see Figure 1: for example, a pipe cleaning system CIP) inside the stirring tank 2 where the bearing 5 coated with dummy liquid is installed (the process of cleaning by the automatic cleaning system 1). After completing the automatic cleaning in step S3, in step S4 the bearing 5 is removed from the stirring tank 2, disassembled, and the remaining amount of the dummy liquid (fluid with a viscosity of a predetermined value or higher) applied in step S1 is inspected (step to inspect the remaining amount of fluid with a viscosity of a predetermined value or higher). In the next step, S5, the remaining amount of dummy liquid, which is the inspection result from step S4, is compared with the threshold (judgment criterion). The threshold is a judgment criterion used to determine whether cleaning is appropriate based on the remaining amount of dummy liquid. For example, the threshold is set to a COD value of 0.5 ppm or less. However, the value and type of the threshold may be changed on a case-by-case basis depending on the type and composition of the fluid being stirred in the stirring tank 2, and other factors such as pH, salinity, and transparency may be used. Based on the comparison in step S5, if the remaining amount of dummy liquid is below the threshold (step S5 is "Yes"), proceed to step S6; if the remaining amount of dummy liquid is greater than the threshold (judgment criterion) (step S5 is "No"), proceed to step S7.

[0034] In step S6, the remaining amount of dummy fluid is below the threshold, and it is determined that the dummy fluid applied to the bearing 5 has been sufficiently removed by automatic cleaning, so the cleaning performance is judged to be acceptable (OK). On the other hand, in step S7, the remaining amount of dummy fluid is greater than the threshold, and it is determined that the dummy fluid applied to the bearing 5 was not sufficiently removed by automatic cleaning, so the cleaning performance is judged as unsatisfactory (NG). Here, steps S5 to S7 are steps to determine whether the remaining amount of organic matter confirmed is below a certain threshold (e.g., 0.5 ppm). After performing step S6 or step S7, proceed to step S8 to confirm whether steps S1 to S7 have been performed for all bearings whose cleaning performance should be tested. If the process has been performed for all bearings 5, including the case where there is only one bearing 5 (step S8 is "Yes"), proceed to step S9. On the other hand, if there are bearings 5 ​​remaining that should be tested for cleaning performance but for which steps S1 to S7 have not been performed (step S8 is "No"), proceed to step S10. In step S8, an overall evaluation is performed for all bearings 5 ​​that have undergone cleaning confirmation testing. This overall evaluation includes the pass rate of the evaluation results and other statistical processing. Then, the cleaning performance test is completed. In step S10, a new bearing 5 that has not yet undergone cleaning performance testing is selected, and steps S1 to S7 are performed. In the cleaning performance verification test method shown in Figure 11, the dummy liquid has a higher viscosity than the fluid handled in the actual manufacturing equipment (e.g., lactic acid bacteria beverage), and if it adheres to the surface of the bearing 5 (or its components), it is difficult to remove. Therefore, if the test shown in Figure 11 using the dummy liquid is cleared, there is no risk of the actual fluid being handled (e.g., lactic acid bacteria beverage) remaining.

[0035] Next, referring primarily to Figure 12, a test method for confirming the cleaning performance of the bearing according to the illustrated embodiment (similar to the performance described with reference to Figure 11) will be explained. In the test method of Figure 12, the specifications of the second cleaning fluid permeable groove G2 (extension direction, and if necessary, depth dimension, width dimension, etc.) are determined, making it possible to set the second cleaning fluid permeable groove G2 formed in the plate 7 to have high cleaning fluid permeability. In Figure 12, in step S11, the stained liquid is injected (applied) for a predetermined time into the second cleaning liquid permeable groove G2 which communicates with the second through hole 7B of the plate 7. Then the process continues to step S12. Step S11 consists of a process of injecting a stained liquid into a second washing liquid permeable groove G2 that communicates with the second through hole 7B. The injected stained liquid flows through the second washing liquid permeable groove G2 into the second through hole 7B, passes over the interface between the outer circumferential surface of the leg portion 8 (plate-side fitting portion 8B) and the inner circumferential surface of the second through hole 7B, flows through the stepped portion 8C which is the boundary between the plate-side fitting portion 8B and the leg support column 8A, and then flows down the leg support column 8A to reach the bottom 2A of the stirring tank 2. When performing step S11, it is not necessary to assemble the bearing 5 into the stirring tank 2. Step S11 may be performed outside the stirring tank 2 before the bush 6, plate 7, and leg 8 that constitute the bearing 5 are assembled inside the stirring tank 2. Of course, it is also possible to perform step S11 by spraying the dyeing liquid from the washing liquid spraying device 4 with the bearing 5 assembled into the stirring tank 2. Furthermore, the injection of the staining solution described above may be performed only through one of the second through-holes 7B.

[0036] In step S12, it is confirmed that the staining solution injected in step S11 has flowed out from the lower surface 7D (back surface) of plate 7 towards the leg support column 8A. In step S13, the bearing 5, from which the leakage of the dyeing liquid in step S12 was confirmed, is disassembled into the bush 6, plate 7, and leg A. In the next step, S14, the degree of staining is inspected and confirmed, particularly in areas where organic matter is known to be highly likely to remain. These designated areas include the boundary between the outer surface of the leg portion 8 and the inner surface of the second through-hole 7B, and the stepped portion 8C (shoulder portion) at the boundary between the plate-side fitting portion 38B and the leg support column 38A, as shown in Figure 5. In step S14, the inspection and confirmation of the degree of staining are performed based on the "area of ​​staining" and the "amount of staining liquid that leaked out," with graded judgment criteria established for each.

[0037] In step S15, as a result of step S14, it is determined whether the permeability of the cleaning solution in the second cleaning solution permeation groove G2 is high and whether the cleaning performance of the bearing 5 in which the groove G2 is formed is high. Specifically, it is determined whether the stained area at the predetermined location is wide and whether the amount of staining liquid that has leaked out at the predetermined location is large, based on the established judgment criteria. In addition to quantitative judgment criteria for "width of the stained area" and "amount of staining liquid that has leaked out," these judgment criteria include graded evaluation points that allow for relative comparison between multiple inspection variables (multiple types of bearings). In step S15, if it is determined that "the stained area is wide" and "the amount of staining liquid that has leaked out is large" (step S15 is "Yes"), proceed to step S16. If "the stained area is not wide (narrow)" and / or "the amount of staining liquid that has leaked out is not large (small)" (step S15 is "No"), proceed to step S17.

[0038] In step S16, where it is determined that "the stained area is wide" and "the amount of staining liquid that has leaked out is large," it is determined that the second cleaning liquid permeability groove G2 is high and that the bearing 5 has high cleaning performance (cleaning performance is determined to be OK). On the other hand, in step S17, where it is determined that "the stained area is not wide (narrow)" and / or "the amount of stained liquid that has leaked out is not large (small)", it is determined that the permeability of the cleaning liquid in the second cleaning liquid permeation groove G2 is poor and that the bearing 5 has low cleaning performance (cleaning performance is determined to be NG). Steps S12 to S17 described above consist of "a process of disassembling the bearing 5 and inspecting the degree of staining in areas that are deemed to have a high probability of containing residual organic matter."

[0039] In the test method shown in Figure 12, steps S11 to S17 are performed for each of the multiple bearings 5 ​​with different extension directions of the second cleaning solution permeable groove G2, and the degree of staining in areas of each bearing 5 that are deemed to have a high probability of residual organic matter is compared. Both steps S16 and S17 are followed by step S18, in which it is determined whether steps S11 to S17 have been completed for all of the multiple bearings 5 ​​(test subjects) with different extension directions of the second cleaning solution permeable groove G2. If steps S11 to S17 have been completed for all test subjects (step S18 is "Yes"), proceed to step S19. If there are any bearings 5 ​​that have not yet undergone steps S11 to S17 (step S18 is "No"), proceed to step S20. In step S19 (if steps S11 to S17 have been completed for all test subjects), the bearing 5 with a wide stained area and a large amount of staining liquid flowing out from a predetermined location is selected (determined) as a bearing 5 with high cleaning performance due to high permeability of the cleaning liquid in the second cleaning liquid permeation groove G2 during automatic cleaning. Then, the extension direction of the second cleaning liquid permeation groove G2 formed on the bearing 5 with high cleaning performance is determined to be a suitable extension direction (as the extension direction of the second cleaning liquid permeation groove G2) for improving the cleaning performance of the bearing 5. This determines the extension direction of the second cleaning liquid permeation groove G2 that improves the permeability of the cleaning liquid and enhances cleaning performance. The test in Figure 12 is also applicable when there is only one bearing 5 under test, in which case the result in step S18 is "Yes". In step S20 (if there are still bearings 5 ​​that have not undergone steps S11 to S17), select one bearing 5 from those that have not undergone steps S11 to S17 and proceed to step S1.

[0040] In the example in Figure 12, the "extension direction of the second cleaning fluid permeable groove G2" was evaluated, but it is also possible to evaluate the "depth and width dimensions of the second cleaning fluid permeable groove G2". According to the test method shown in Figure 12, the second cleaning fluid permeable groove G2 can be configured to improve the permeability of the cleaning fluid, and to increase the amount of cleaning fluid permeated, particularly at the boundary between the outer surface of the leg portion 8 and the inner surface of the second through hole 7B, and at the stepped portion 8C (shoulder portion) of the leg portion 8, which is the boundary between the plate-side fitting portion 8B and the leg support column 8A.

[0041] The illustrated embodiments are for illustrative purposes only and are not intended to limit the technical scope of the present invention. [Explanation of symbols]

[0042] 1. Automatic cleaning system 2. Mixing tank 2A...Bottom of the stirring tank 3... Stirring shaft 3A... Stirring blade 5. Bearings 6. Bush 6A... Bushing body 6B...Flange 6D... Bush opening 6I... Chamfering of bush opening 6J... Top surface of the bush 6K... Underside of the bush 7.. Plate 7A...First through hole 7B...Second through hole 7BO...Center point of the second through hole 7C... Top surface of the plate 7D...Underside of the plate 7PL... Long side of the plate 7PS... Short side of the plate 8...legs 8A...Leg support 8B...(Leg part) Plate side fitting part G1...First groove for cleaning fluid permeation G1A... First Domain G1B...Second Domain G1C... Third Domain G2...Second groove for cleaning fluid permeation

Claims

1. In a bearing that supports a rotating shaft having a stirring blade, provided in a stirring tank, A bush is provided at the bottom of the stirring tank into which the lower end of the rotating shaft is inserted, The bush is fitted into a through hole formed in the center of a plate that is attached to the leg portion provided at the bottom of the stirring tank. A chamfer is formed on the upper edge of the opening into which the lower end of the rotating shaft of the bush is inserted. A bearing characterized in that a first cleaning fluid permeable groove is formed on the side surface of the bush, extending continuously from the upper surface to the lower surface of the bush.

2. The first cleaning fluid permeable groove has a first region extending vertically from the lower surface of the bush, a second region communicating with the first region and extending circumferentially to the bush, and a third region communicating with the second region, extending vertically to the bush and reaching the upper surface of the bush. The bush is provided with a flange, and the outer diameter of the flange is larger than the inner diameter of the through hole. The bearing according to claim 1, wherein the region of the flange to which the third region of the first cleaning fluid permeable groove extends is cut out.

3. In a bearing that supports a rotating shaft having a stirring blade, provided in a stirring tank, A rectangular plate is provided at the bottom of the stirring tank to house a bush into which the lower end of the rotating shaft is inserted. The plate has a first through-hole for housing the bush and a second through-hole into which the legs protruding from the bottom of the stirring tank are inserted. The bearing is characterized in that a plurality of second cleaning fluid permeable grooves (for example, four grooves for a single second through hole) are formed on the upper and lower surfaces of the plate, communicating with the second through hole.

4. The bearing according to claim 3, wherein the second cleaning fluid permeable groove extends with an inclination angle of 30° to 60° with respect to a virtual line passing through the center point of the second through hole and parallel to the long or short side of the plate.

5. In a bearing that supports a rotating shaft having a stirring blade, provided in a stirring tank, A bush is provided at the bottom of the stirring tank into which the lower end of the rotating shaft is inserted, The bush is fitted into a through hole formed in the center of a plate that is attached to the leg portion provided at the bottom of the stirring tank. A chamfer is formed on the upper edge of the opening into which the lower end of the rotating shaft of the bush is inserted. A first cleaning fluid permeable groove is formed on the side surface of the bush, extending continuously from the top surface to the bottom surface of the bush. The plate has a first through-hole for housing the bush and a second through-hole into which the legs protruding from the bottom of the stirring tank are inserted. The bearing is characterized in that a plurality of second cleaning fluid permeable grooves communicating with the second through hole are formed on the upper and lower surfaces of the plate.

6. The first cleaning fluid permeable groove has a first region extending vertically from the lower surface of the bush, a second region communicating with the first region and extending circumferentially to the bush, and a third region communicating with the second region, extending vertically to the bush and reaching the upper surface of the bush. The bush is provided with a flange, and the outer diameter of the flange is larger than the inner diameter of the first through hole. The region of the flange to which the third region of the first cleaning fluid permeable groove extends is cut out. The bearing according to claim 5, wherein the second cleaning fluid permeable groove extends with an inclination angle of 30° to 60° with respect to a virtual line passing through the center point of the second through hole and parallel to the long or short side of the plate.

7. In a test method for confirming the cleaning performance of a bearing according to any one of claims 1 to 6, A step of applying a fluid having a viscosity of a predetermined value or higher to the bearing, A step of cleaning the bearing to which the fluid has been applied using an automatic cleaning system, A step of inspecting the remaining amount of fluid having a viscosity of a predetermined value or higher, A test method characterized by having a step of determining whether the remaining amount of confirmed organic matter is below a certain threshold.

8. In a test method for confirming the cleaning performance of a bearing according to any one of claims 3 to 6, A step of injecting a stained liquid into one of the second cleaning liquid permeable grooves that communicate with the second through hole formed in the plate, The process includes, after injecting the stained liquid, disassembling the bearing and inspecting the degree of staining in areas where organic matter is deemed likely to remain, For each of the plurality of bearings whose second cleaning fluid permeable grooves have different extension directions, the steps of injecting the stained liquid and inspecting the degree of staining are performed, and the degree of staining is compared in each bearing at locations that are previously deemed to have a high probability of containing organic matter. A test method characterized by including a step of determining that a bearing with a wide stained area in a location previously identified as having a high probability of residual organic matter is a bearing with high cleaning performance due to high permeability of the cleaning solution in the second cleaning solution permeation groove during automatic cleaning.

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