Roller Tire Assembly

Abstract

To provide a roller tire assembly which enables a user to monitor a state of a lubrication oil easily.SOLUTION: A roller tire assembly 50 for crushing a material into powder includes: a roller tire 51; a roller shaft 52 which is inserted into the radial inner side of the roller tire 51; a bearing 53 which is disposed between the roller shaft 52 and the roller tire 51 and supports the roller tire 51 in a manner that the roller tire 51 can rotate relative to the roller shaft 52; and a lubrication oil circulation passage 60 which connects the interior of a bearing chamber R1, in which the bearing 53 is disposed, with the exterior of the roller tire assembly 50.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a roller tire assembly. [Background technology]

[0002] A roller tire assembly is used to obtain powder such as pulverized fuel or powdered raw material. Patent Document 1 discloses a vertical mill as an apparatus equipped with such a roller tire assembly. This vertical mill includes a roller shaft, mill rollers, and a mill roller bearing. The mill roller bearing is disposed in a bearing chamber between the roller shaft and the mill roller. Lubricating oil for the mill roller bearing is sealed in the bearing chamber (so-called oil bath system). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-36964 A Summary of the Invention [Problem to be solved by the invention]

[0004] In roller tire assemblies such as those described above, it is desirable to be able to easily monitor the condition of the lubricant to maintain good lubrication of the bearings.

[0005] In consideration of the above problems, the present disclosure aims to provide a roller tire assembly that allows easy monitoring of the condition of the lubricant. [Means for solving the problem]

[0006] In order to solve the above problems, according to one aspect of the present disclosure, a roller tire assembly for grinding a material into powder includes a roller tire, a roller shaft inserted radially inside the roller tire, at least one bearing disposed between the roller shaft and the roller tire and rotatably supporting the roller tire relative to the roller shaft, and a lubricating oil circulation path connecting an interior of a bearing chamber in which the at least one bearing is disposed and an exterior of the roller tire assembly. a pivot shaft that supports the roller shaft so as to be swingable about a central axis that is horizontal and perpendicular to the central axis of the roller shaft; Equipped with The circulation path has a lubricant supply path including a first section passing through the pivot shaft and a second section passing through the roller shaft, and a lubricant return path including a third section passing through the roller shaft and a fourth section passing through the pivot shaft, and on the pivot shaft, one of the first section and the fourth section is located inside the other of the first section and the fourth section. .

[0009] The roller tire assembly may further comprise a suction pipe communicating with the third section of the return path and projecting from the roller shaft into the bearing chamber, the suction pipe having a lubricant return port, the return port being parallel to a desired lubricant oil level in the bearing chamber.

[0010] The return port may be located above the bottom of the outer ring for all of the at least one bearing.

[0011] The roller tire assembly may further include a gas flow passage connecting the bearing chamber with the outside.

[0012] The gas flow path may include an air supply passage and an exhaust passage through the pivot shaft, and one of the air supply passage and the exhaust passage may be located inside the other of the air supply passage and the exhaust passage at the pivot shaft.

[0013] The exhaust passage may further pass through the roller shaft and may have a gas return port on the roller shaft, the gas return port being located above the lubricant return port.

[0014] Another aspect of the present disclosure includes a pulverizer comprising the roller tire assembly described above and a monitoring device connected to the circulation path for measuring the concentration of magnetic powder in the lubricating oil. Effect of the Invention

[0015] According to the present disclosure, the condition of the lubricant can be easily monitored. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic cross-sectional side view showing a crusher equipped with a roller tire assembly according to an embodiment. [Diagram 2] FIG. 2 is an enlarged schematic cross-sectional side view of the roller tire assembly of FIG. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The specific dimensions, materials, numerical values, etc. shown in the embodiments are merely examples for facilitating understanding, and do not limit the present disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid repeated explanations, and elements not directly related to the present disclosure are omitted from the drawings.

[0018] FIG. 1 is a schematic side cross-sectional view showing a pulverizer 100 including a roller tire assembly 50 according to an embodiment. In this embodiment, the roller tire assembly 50 is applied to the pulverizer 100 for obtaining pulverized coal (powder) from coal (material). In other embodiments, the roller tire assembly 50 may be applied to other devices for pulverizing other materials (e.g., raw materials or biomass, etc.). The pulverizer 100 includes a casing 1, a table 2, a plurality of roller tire assemblies 50 (only one roller tire assembly 50 is shown in FIG. 1), and a monitoring device 90. The pulverizer 100 may further include other components.

[0019] The casing 1 has, for example, a generally cylindrical shape and is provided with its central axis vertical. A cylindrical chute 11 for feeding coal into the inside of the casing 1 is provided in the center of the upper part of the casing 1. The chute 11 is provided with its central axis vertical. A cylindrical outlet portion 16 is provided on the side of the chute 11 in the upper part of the casing 1. Furthermore, inside the casing 1, a reject chute 12 and a rotary classifier 13 are provided around the chute 11. The reject chute 12 has, for example, an inverted truncated cone shape and is arranged coaxially with the chute 11. The reject chute 12 is provided with a slit 12a.

[0020] The table 2 is provided below the chute 11 inside the casing 1. The table 2 has a roughly disk-shaped portion. The table 2 is rotated around a vertical axis by, for example, a motor 3 via a reducer 4. An annular groove 2a is formed on the upper surface of the table 2.

[0021] A plurality of air ports 14 (only one air port 14 is shown in FIG. 1) are provided around the table 2. A primary air chamber 17 is defined below the table 2 and communicates with the air port 14. Air is supplied to the primary air chamber 17 from a duct 15. With this configuration, air is blown upward from the air port 14 around the table 2.

[0022] The roller tire assembly 50 is provided inside the casing 1 on a side wall of the casing 1. A plurality of roller tire assemblies 50 are arranged around the table 2, spaced apart from one another along the circumferential direction of the table 2. A roller tire 51 of the roller tire assembly 50 has a profile that engages with the groove 2a of the table 2. The roller tire 51 is driven by the rotation of the table 2 due to friction between the roller tire 51 and the groove 2a.

[0023] The roller tire assembly 50 is swingable about a horizontal pivot shaft 58, and is pushed in the swinging direction by a cylinder 5, such as a hydraulic cylinder, via a plunger 6. With this configuration, the roller tire 51 is pressed against the groove 2a of the table 2. When the roller tire 51 contacts the groove 2a, the central axis of the roller tire 51 is inclined with respect to the horizontal direction so that the end on the roller tire 51 side is positioned lower than the end on the pivot shaft 58 side.

[0024] In the pulverizer 100 as described above, coal is fed into the casing 1 through the chute 11. The coal falls onto the upper surface of the table 2 and is pulverized into pulverized coal by the roller tires 51 and the grooves 2a of the table 2. The pulverized coal is lifted by air from the air port 14. The pulverized coal passes through the slits 12a of the reject chute 12, and the coarse particles are removed by the classifier 13. The pulverized coal that has passed through the classifier 13 is sent from the outlet 16 to a subsequent process (e.g., a boiler burner).

[0025] The monitoring device 90 is provided outside the casing 1. The monitoring device 90 is connected to the circulation path 60 of the roller tire assembly 50 described below, and measures the concentration of magnetic powder (for example, iron powder) in the lubricating oil flowing through the circulation path 60.

[0026] Next, the roller tire assembly 50 will be described in detail.

[0027] 2 is a schematic enlarged cross-sectional side view showing the roller tire assembly 50 in FIG. 1. The roller tire assembly 50 includes a roller tire 51, a roller shaft 52, a bearing 53, a bearing cover 54, a seal casing 55, a seal ring 56, a bracket 57, a pivot shaft 58, a circulation path 60, and an air breather (gas flow path) 70. The roller tire assembly 50 may further include other components. For better understanding, the end on the roller tire 51 side (the end on the right side in FIG. 2) will be referred to as the "front end" and the end on the pivot shaft 58 side (the end on the left side in FIG. 2) will be referred to as the "rear end" in relation to the direction of the roller tire assembly 50 and its components.

[0028] As described above, the roller tire 51 cooperates with the table 2 to pulverize the coal into pulverized coal. The roller shaft 52 is inserted radially inside the roller tire 51 to support the roller tire 51. The roller tire 51 is disposed at approximately the front half of the roller shaft 52. As described above, when the roller tire 51 contacts the groove 2a of the table 2, the roller shaft 52 is inclined at an angle α (for example, 0 to 30 degrees) with respect to the horizontal direction so that the front end 52a is positioned lower than the rear end 52b. Note that the roller shaft 52 does not rotate around its central axis.

[0029] The bearing 53 is disposed between the roller tire 51 and the roller shaft 52, and supports the roller tire 51 rotatably relative to the roller shaft 52. In this embodiment, the bearing 53 includes a first bearing 53a and a second bearing 53b along the central axis of the roller shaft 52. The bearings 53a and 53b are spaced apart from each other in the axial direction by a spacer 53c.

[0030] The bearing cover 54 has a generally disk shape, and is fixed in a fluid-tight manner to the tip surface of the roller tire 51. The bearing cover 54 rotates together with the roller tire 51.

[0031] The seal casing 55 has an annular shape and is fixed in a fluid-tight manner to an annular groove provided in the rear end surface of the roller tire 51. The seal casing 55 rotates together with the roller tire 51. The inner circumferential surface of the seal casing 55 is slightly spaced from the outer circumferential surface of the roller shaft 52 via a sealing element such as an oil seal. The seal casing 55 is provided in a liquid-tight manner with respect to the roller shaft 52.

[0032] In this embodiment, a bearing chamber R1 is defined by the roller tire 51, roller shaft 52, bearing cover 54, and seal casing 55. The bearing chamber R1 contains lubricating oil L for the bearing 53. The lubricating oil L is circulated between the bearing chamber R1 and the outside of the roller tire assembly 50 by a circulation path 60 (described in detail later). In addition, the liquid level of the lubricating oil L is controlled to be maintained at a constant height (described in detail later).

[0033] The seal ring 56 has an outer ring 56a and an inner ring 56b. The outer ring 56a has a generally annular shape and is fixed to the rear end surface of the roller tire 51 in a fluid-tight manner. The outer ring 56a rotates together with the roller tire 51. The inner ring 56b has a generally annular shape smaller than the outer ring 56a and is provided radially inside the outer ring 56a. The inner ring 56b is fixed to a tip surface of a bracket 57 in a fluid-tight manner. The bracket 57 does not rotate around the central axis of the roller shaft 52. Therefore, the outer ring 56a rotates relative to the inner ring 56b fixed to the bracket 57. The inner ring 56b and the bracket 57 are provided with an air passage 56c that allows gas to pass between the bearing chamber R1 and a shaft chamber R2 described later.

[0034] The bracket 57 has a shaft chamber R2 that houses at least a portion of each of the roller shaft 52 and the pivot shaft 58. Specifically, the bracket 57 is provided so as to cover approximately the rear end half of the roller shaft 52, and is fixed in a fluid-tight manner to the rear end 52b of the roller shaft 52 via an end plate 57a. The bracket 57 also covers a middle portion of the pivot shaft 58 excluding the areas near both ends (described in detail later).

[0035] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. For better understanding, FIG. 3 mainly shows the casing 1, roller shaft 52, pivot shaft 58, circulation path 60, and air breather 70 of the crusher 100, and omits some other components (e.g., bracket 57, etc.). The pivot shaft 58 is rotatably supported by the casing 1 via a support element such as a pivot bearing 58a so that its central axis is horizontal. Although not shown in FIG. 3, the bracket 57 covers the large-diameter middle portion of the pivot shaft 58, excluding the vicinity of both ends. Referring to FIG. 2, the bracket 57 is supported by the pivot shaft 58 so that the central axis of the roller shaft 52 is perpendicular to the central axis of the pivot shaft 58. Therefore, the entire components from the bracket 57 at the rear end to the roller tire 51 at the front end are supported by the pivot shaft 58 so that they can be rocked around the central axis of the pivot shaft 58.

[0036] As described above, the circulation path 60 circulates the lubricating oil L between the bearing chamber R1 and the outside (monitoring device 90) of the roller tire assembly 50. The circulation path 60 has an oil supply path 61 and a return path 62.

[0037] 3, the oil supply passage 61 includes a first section 61a passing through the pivot shaft 58 and a second section 61b passing through the roller shaft 52. The first section 61a and the second section 61b are connected by a pipe P1. The return passage 62 includes a third section 62a passing through the roller shaft 52 and a fourth section 62b passing through the pivot shaft 58. The third section 62a and the fourth section 62b are connected by a pipe P2. Referring to FIG. 2, the pipes P1 and P2 pass through the shaft chamber R2 covered by the bracket 57. Therefore, the pipes P1 and P2 are not exposed to powder.

[0038] With reference to FIG. 3, in this embodiment, the first section 61a of the oil supply passage 61 is formed radially inside the fourth section 62b of the return passage 62. Specifically, for example, with respect to the pivot shaft 58, a pilot hole 62c is formed along the central axis of the pivot shaft 58 (for example, on the central axis) from a first end (the end on the left side in FIG. 3) to approximately the center. Next, a hole h1 is formed perpendicular to the pilot hole 62c near the deepest part of the pilot hole 62c. Next, a hole h2 is formed perpendicular to the pilot hole 62c, spaced apart from the hole h1. Next, a pipe 61c is inserted into the pilot hole 62c. The pipe 61c is thinner than the pilot hole 62c. A tip 61d of the pipe 61c is positioned between the hole h1 and the hole h2 in the central axis direction. The tip 61d is in liquid-tight contact with the wall surface of the pilot hole 62c via a seal element such as an O-ring (not shown). According to the above-mentioned configuration, the first section 61a of the oil supply passage 61 is defined inside the pipe 61c, and the fourth section 62b of the return passage 62 is defined between the lower hole 62c and the outer wall of the pipe 61c. That is, in the pivot shaft 58, the first section 61a and the fourth section 62b form a double-pipe structure, and in this embodiment, the first section 61a of the oil supply passage 61 is located inside the fourth section 62b of the return passage 62. In other embodiments, the inside of the pipe 61c may be used as the fourth section 62b of the return passage 62, and the gap between the lower hole 62c and the outer wall of the pipe 61c may be used as the first section 61a of the oil supply passage 61. In this case, for example, in the roller shaft 52, the pipe P1 may be connected to the third section 62a instead of the second section 61b, and the pipe P2 may be connected to the second section 61b instead of the third section 62a.

[0039] One of the openings of the three-way pipe 61e is attached to the entrance of the lower hole 62c. The pipe 61c passes through the other one of the openings of the three-way pipe 61e in a fluid-tight manner. The inner diameter of the part of the three-way pipe 61e through which the pipe 61c passes is larger than the outer diameter of the pipe 61c. Thus, a gap is defined between the inner wall of the three-way pipe 61e and the outer wall of the pipe 61c. The gap functions as a part of the return path 62. The entrance 61f of the pipe 61c is located outside the casing 1. The remaining opening of the three-way pipe 61e is the exit 62d of the return path 62.

[0040] 2, the second section 61b of the oil supply passage 61 and the third section 62a of the return passage 62 penetrate along the central axis of the roller shaft 52 to the tip of the roller shaft 52. In addition, in FIG. 2, the third section 62a of the return passage 62 of the circulation passage 60 and the second section 72a of the exhaust passage 72 of the air breather 70 described later overlap in the direction perpendicular to the paper surface, and the third section 62a of the return passage 62 is located behind the second section 72a of the exhaust passage 72. The second section 61b of the oil supply passage 61 is located below the third section 62a of the return passage 62.

[0041] A suction pipe 63 is connected to the third section 62a of the return passage 62. The suction pipe 63 is connected to the return passage 62. The suction pipe 63 protrudes from the tip 52a of the roller shaft 52 into the bearing chamber R1. The suction pipe 63 includes a return port 63a. The return port 63a sucks the lubricating oil L from the bearing chamber R1. The return port 63a is formed parallel to the planned oil level of the lubricating oil L in the bearing chamber R1. That is, the return port 63a is formed so as to be inclined at an angle α with respect to the central axis of the roller shaft 52. Since the return port 63a is parallel to the oil level of the lubricating oil L, the intrusion of air from the edge of the return port 63a can be reduced, and the lubricating oil L can be efficiently sucked. In addition, when the amount of oil becomes low, the suction of oil stops. Therefore, the oil supply to the bearing 53 is not interrupted, and bearing failure or mill stoppage can be prevented. In this way, oil reduction can also be prevented at the same time. Furthermore, the return port 63a is located above the lowest part of the outer ring for each of the bearings 53a and 53b. That is, it is intended that at least a part of each of the bearings 53a and 53b is located below the oil level of the lubricating oil L. More specifically, in this embodiment, the return port 63a is designed such that at least half of the cross section of the lowest part of the uppermost bearing 53a is located below the return port 63a.

[0042] 3, in the circulation path 60 as described above, the inlet 61f of the oil supply path 61 and the outlet 62d of the return path 62 are connected to the monitoring device 90 (see FIG. 1) via piping. The piping may be provided with components (not shown) such as a pump for pumping the lubricating oil L, a pump for generating negative pressure for sucking the lubricating oil L from the bearing chamber R1, and a filter. The lubricating oil L enters the inlet 61f of the oil supply path 61 and flows through the first section 61a in the pivot shaft 58. The lubricating oil L is sent from the first section 61a to the second section 61b in the roller shaft 52 via the piping P1.

[0043] 2, the lubricating oil L flows through the second section 61b and is discharged into the bearing chamber R1 from the outlet at the tip 52a of the roller shaft 52. The lubricating oil L in the bearing chamber R1 is sucked through the return port 63a of the suction pipe 63 by negative pressure and flows through the third section 62a of the return path 62 in the roller shaft 52.

[0044] 3, the lubricating oil L is sent from the third section 62a through the pipe P2 to the fourth section 62b in the pivot shaft 58. The lubricating oil L flows through the fourth section 62b and is sent to the outside of the roller tire assembly 50 (monitoring device 90) from the outlet 62d of the return path 62. The monitoring device 90 measures the concentration of magnetic powder in the lubricating oil L.

[0045] The air breather 70 connects the bearing chamber R1 to the outside of the roller tire assembly 50. The air breather 70 has an air supply path 71 that supplies gas (e.g., air) to the bearing chamber R1, and an exhaust path 72 that exhausts gas from the bearing chamber R1.

[0046] The air supply passage 71 (first section) passes through the pivot shaft 58 and communicates with the inside of the bracket 57 and further with the bearing chamber R1. In this embodiment, the air supply passage 71 does not pass through the roller shaft 52. However, in other embodiments, the air supply passage 71 may pass through the roller shaft 52. The exhaust passage 72 includes a second section 72a that passes through the roller shaft 52 and a third section 72b that passes through the pivot shaft 58. The third section 72b and the second section 72a are connected by a pipe P3. With reference to FIG. 2, the pipe P3 is covered by the bracket 57 and is therefore not exposed to powder.

[0047] With reference to FIG. 3, in this embodiment, the air supply passage 71 is formed radially inside the third section 72b of the exhaust passage 72. Specifically, for example, with respect to the pivot shaft 58, a pilot hole 72c is formed along the central axis of the pivot shaft 58 (for example, on the central axis) from the second end (the end on the right side in FIG. 3) to approximately the center. The pilot hole 72c is formed so as not to connect with the pilot hole 62c of the circulation passage 60. Next, a plurality of holes h3 (three in FIG. 3) are formed perpendicular to the pilot hole 72c near the deepest part of the pilot hole 72c. Next, a hole h4 is formed perpendicular to the pilot hole 72c, separated from the hole h3. Next, a pipe 71c is inserted into the pilot hole 72c. The pipe 71c is thinner than the pilot hole 72c. A tip 71d of the pipe 71c is positioned between the hole h3 and the hole h4 in the central axis direction. The tip 71d is in liquid-tight contact with the wall surface of the lower hole 72c via a sealing element such as an O-ring (not shown). According to the above-mentioned configuration, the air supply passage 71 is defined inside the pipe 71c, and the third section 72b of the exhaust passage 72 is defined between the lower hole 72c and the outer wall of the pipe 71c. That is, in the pivot shaft 58, the air supply passage 71 and the third section 72b of the exhaust passage 72 form a double pipe structure, and in this embodiment, the air supply passage 71 is located inside the third section 72b of the exhaust passage 72. In other embodiments, the inside of the pipe 71c may be used as the exhaust passage 72, and the gap between the lower hole 72c and the outer wall of the pipe 71c may be used as a part of the air supply passage 71.

[0048] One of the openings of the three-way pipe 71e is attached to the inlet of the lower hole 72c. The pipe 71c passes through the other one of the openings of the three-way pipe 71e in a fluid-tight manner. The inner diameter of the part of the three-way pipe 71e through which the pipe 71c passes is larger than the outer diameter of the pipe 71c. Thus, a gap is defined between the inner wall of the three-way pipe 71e and the outer wall of the pipe 71c. The gap functions as a part of the exhaust path 72. The inlet 71f of the pipe 71c is located outside the casing 1. The remaining outlet of the three-way pipe 71e is the outlet 72d of the exhaust path 72.

[0049] 2, the second section 72a of the exhaust passage 72 penetrates along the central axis of the roller shaft 52 to the tip 52a of the roller shaft 52. An inlet (gas return port) 73 of the exhaust passage 72 (second section 72a) at the tip 52a is positioned above the expected liquid level of the lubricating oil L (i.e., the return port 63a of the suction pipe 63).

[0050] 3, in the air breather 70 as described above, in order to maintain the bearing chamber R1 at a constant pressure (for example, external air pressure or positive pressure, etc.), an inlet 71f of an air supply passage 71 is connected to a compressor to send gas (for example, air) to the bearing chamber R1. The gas enters the inlet 71f and flows through the air supply passage 71 in the pivot shaft 58. The gas is supplied to the bearing chamber R1 from the hole h3, through the inside of the bracket 57, and further through the air passage 56c.

[0051] 2, the gas in the bearing chamber R1 is pushed out to the inlet of the exhaust passage 72 at the tip 52a of the roller shaft 52 by the newly supplied gas, and flows through the second section 72a in the roller shaft 52. As shown in FIG.

[0052] 3, the gas is sent from the second section 72a through a pipe P3 to a third section 72b in the pivot shaft 58. The gas flows through the third section 72b and is discharged from an outlet 72d of the exhaust passage 72 to the outside of the roller tire assembly 50.

[0053] The roller tire assembly 50 as described above includes a roller tire 51, a roller shaft 52 inserted radially inside the roller tire 51, at least one bearing 53 disposed between the roller shaft 52 and the roller tire 51 and supporting the roller tire 51 rotatably relative to the roller shaft 52, and a circulation path 60 for the lubricant L that connects the bearing chamber R1 in which the at least one bearing 53 is disposed to the outside of the roller tire assembly 50. When the oil bath method is used as in Patent Document 1, the lubricant L is sealed in the bearing chamber R1. In this case, in order to monitor the state of the lubricant L, it is necessary to stop the roller tire assembly 50 and collect the lubricant L from the bearing chamber R1. Therefore, it may be necessary to stop the equipment (e.g., a boiler) that uses the roller tire assembly 50, and the availability rate of the equipment may decrease. In contrast, in the roller tire assembly 50 of this embodiment, the lubricant L can be sent to the outside by the circulation path 60. Therefore, the state of the lubricant L can be monitored outside the roller tire assembly 50 without stopping the roller tire assembly 50. Therefore, the state of the lubricating oil L (i.e., the wear state of the bearings 53) can be easily monitored. This allows the roller tire assembly 50 and the equipment using the roller tire assembly 50 to continue operating.

[0054] The roller tire assembly 50 further includes a pivot shaft 58 that supports the roller shaft 52 so as to be swingable around a central axis that is horizontal and perpendicular to the central axis of the roller shaft 52, and the circulation path 60 includes an oil supply path 61 for the lubricating oil L including a first section 61a that passes through the pivot shaft 58 and a second section 61b that passes through the roller shaft 52, and a return path 62 for the lubricating oil L including a third section 62a that passes through the roller shaft 52 and a fourth section 62b that passes through the pivot shaft 58. With this configuration, the circulation path 60 passes through the inside of the roller shaft 52 and the inside of the pivot shaft 58. Therefore, the circulation path 60 is not exposed to the space where the pulverized coal is formed. This reduces the risk of the pulverized coal entering the circulation path 60. In addition, the circulation path 60 can be prevented from being worn by the pulverized coal.

[0055] Furthermore, in the roller tire assembly 50, the first section 61a is located inside the fourth section 62b in the pivot shaft 58. In this manner, the oil supply passage 61 and the return passage 62 form a double-pipe structure in the pivot shaft 58. Therefore, it is possible to provide the circulation passage 60 while suppressing a reduction in the cross-sectional area of ​​the pivot shaft 58. Therefore, it is possible to maintain the structural strength of the pivot shaft 58.

[0056] The roller tire assembly 50 also includes a suction pipe 63 that communicates with the third section 62a of the return path 62 and protrudes from the tip 52a of the roller shaft 52 into the bearing chamber R1, the suction pipe 63 having a return port 63a for the lubricating oil L, and the return port 63a is parallel to the planned oil level of the lubricating oil L in the bearing chamber R1. Since the return port 63a is parallel to the oil level of the lubricating oil L, the intrusion of air from the edge of the return port 63a can be reduced, and the lubricating oil L can be efficiently sucked in. Therefore, the height of the oil level of the lubricating oil L in the bearing chamber R1 can be maintained constant. Therefore, it is possible to prevent excess lubricating oil from being stored in the bearing chamber R1, and to prevent an increase in the rotational resistance of the roller tire 51.

[0057] Furthermore, in the roller tire assembly 50, the return port 63a of the lubricating oil L is located above the lowermost part of the outer ring for at least one of the bearings 53a, 53b. That is, it is intended that at least a part of each of the bearings 53a, 53b is located below the oil level of the lubricating oil L. Therefore, the lubricating oil L can be supplied to all of the bearings 53a, 53b, and damage to the bearings 53a, 53b can be suppressed.

[0058] The roller tire assembly 50 further includes an air breather 70 that connects the bearing chamber R1 to the outside of the roller tire assembly 50. Therefore, the air breather 70 can supply gas to the bearing chamber R1, and the bearing chamber R1 can be maintained at a constant pressure. This can prevent powder from being sucked into the bearing chamber R1 by negative pressure.

[0059] Moreover, in the roller tire assembly 50, the air breather 70 has an air intake passage 71 and an exhaust passage 72 that pass through the pivot shaft 58, and in the pivot shaft 58, the air intake passage 71 is located inside the third section 72b of the exhaust passage 72. In this manner, the air intake passage 71 and the exhaust passage 72 form a double pipe structure in the pivot shaft 58. Therefore, the air breather 70 can be provided while suppressing a reduction in the cross-sectional area of ​​the pivot shaft 58. Therefore, the structural strength of the pivot shaft 58 can be maintained.

[0060] Furthermore, in the roller tire assembly 50, the second section 72a of the exhaust path 72 passes through the roller shaft 52 and has a gas return port 73 on the roller shaft 52, and the gas return port 73 is located above the return port 63a of the lubricating oil L. Therefore, the gas return port 73 is located above the expected oil level of the lubricating oil L. Therefore, it is possible to suppress the intrusion of the lubricating oil L into the gas return port 73.

[0061] The crusher 100 also includes the roller tire assembly 50 as described above, and a monitoring device 90 that is connected to the circulation path 60 and measures the concentration of magnetic powder in the lubricating oil L. Therefore, the monitoring device 90 can constantly monitor the state of the lubricating oil L (i.e., the wear state of the bearings 53). Therefore, wear of the bearings 53 can be detected at an early stage, and thus a schedule for replacing the bearings 53, etc. can be easily created.

[0062] Although the embodiments have been described above with reference to the accompanying drawings, the present disclosure is not limited to the above-described embodiments. It is clear that a person skilled in the art can think of various modified or altered examples within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present disclosure.

[0063] For example, in the above embodiment, the pulverizer 100 includes the monitoring device 90. However, in other embodiments, the pulverizer 100 may not include the monitoring device 90. In this case, the lubricant L may be collected from the circulation path 60, and the state of the lubricant L may be analyzed by another device.

[0064] The disclosure can promote better energy supply through better facilities, contributing to the United Nations-led Sustainable Development Goals (SDGs) Goal 7 "Ensure access to affordable, reliable, sustainable and modern energy", Goal 12 "Ensure sustainable consumption and production patterns" and Goal 13 "Take urgent action to combat climate change and its impacts". [Explanation of symbols]

[0065] 50 Roller Tire Assembly 51 Roller Tire 52 Roller shaft 53 Bearings 58 Pivot Axis 60 Circulation path 61 Fuel Line 61a 1st Section 61b 2nd Section 62 Return 62a Section 3 62b Section 4 63 Suction pipe 63a Return entrance 70 Air breather (gas flow path) 90 Monitoring equipment 100 Crusher L Lubricating oil R1 Bearing chamber

Claims

1. 1. A roller tire assembly for reducing material to a powder, comprising: Roller tires and A roller shaft is inserted radially inside the roller tire; and At least one bearing disposed between the roller shaft and the roller tire for rotatably supporting the roller tire relative to the roller shaft; a lubricant circulation path connecting the inside of a bearing chamber in which the at least one bearing is disposed and the outside of the roller tire assembly; a pivot shaft that supports the roller shaft so as to be swingable about a central axis that is horizontal and perpendicular to the central axis of the roller shaft; Equipped with The circulation path includes: an oil supply passage for the lubricating oil including a first section passing through the pivot shaft and a second section passing through the roller shaft; a lubricant return path including a third section passing through the roller shaft and a fourth section passing through the pivot shaft; having In the pivot shaft, one of the first section and the fourth section is located inside the other of the first section and the fourth section. Roller tire assembly.

2. The roller shaft further includes a suction pipe that is connected to the third section of the return path and protrudes from the roller shaft into the bearing chamber, the suction pipe having a return port for the lubricating oil. The return port is parallel to a planned oil level of the lubricating oil in the bearing chamber.

2. The roller tire assembly of claim 1.

3. 3. The roller tire assembly of claim 2, wherein the return port is located above a bottom of the outer wheel for all of the at least one bearing.

4. The roller tire assembly according to any one of claims 1 to 3, further comprising a gas flow passage connecting the bearing chamber and the outside.

5. the gas flow path includes an air supply path and an exhaust path that pass through the pivot shaft, 5. The roller tire assembly of claim 4, wherein at said pivot axis, one of said air supply passage and said exhaust passage is located inside the other of said air supply passage and said exhaust passage.

6. the exhaust path further passes through the roller shaft and has a gas return port on the roller shaft; 6. A roller tire assembly according to claim 5, which relies on claim 4 which relies on claim 2 or 3, wherein the gas return port is located above the lubricating oil return port.

7. The roller tire assembly according to any one of claims 1 to 6; A monitoring device connected to the circulation path for measuring the concentration of magnetic powder in the lubricating oil; A crusher comprising:

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