WO2020013082A1

WO2020013082A1 - Method for manufacturing grinding roller and temperature-raising device

Info

Publication number: WO2020013082A1
Application number: PCT/JP2019/026730
Authority: WO
Inventors: 貴之梅野; 大坪　栄一郎; 悠一廣瀬; 大成池村
Original assignee: 三菱日立パワーシステムズ株式会社
Priority date: 2018-07-13
Filing date: 2019-07-04
Publication date: 2020-01-16
Also published as: CN112292209B; CN112292209A; KR20210011430A; JP2020011164A; JP7102270B2; KR102431648B1

Abstract

This method is for manufacturing a grinding roller that is provided with: a journal housing that is rotatably supported with respect to the housing of a grinder; and an annular roller (24) that has an annular base (25) and a hardened part (26), which is provided on the outer circumferential surface of the base (25) and has a smaller coefficient of thermal expansion than the base (25). This method for manufacturing the grinding roller comprises: a heating step for heating the roller (24) from the outer circumferential surface with the roller (24) disposed so that the central axis line (C1) thereof is orthogonal to the floor and the inner circumferential surface is open to outside air; a placement step for placing the journal housing and the roller (24), the temperature of which has been raised by the heating step, so that the inner circumferential surface of the roller (24) and the outer circumferential surface of the journal housing face or contact each other; and a fitting step for cooling the roller (24), which has been placed in the placement step, and fitting the journal housing together with the roller (24).

Description

Method for manufacturing crushing roller and heating device

The present invention relates to a method for manufacturing a crushing roller and a temperature raising device.

A pulverizing table that rotates around a vertical axis as a pulverizer that pulverizes a solid fuel such as coal into a fine powder having a particle size smaller than a predetermined particle size and supplies it to a combustion device. 2. Description of the Related Art A pulverizer that pulverizes an object to be pulverized placed thereon by being pressed by a pulverizing roller rotatably supported inside the pulverizer is known.

A crushing roller used in such a crusher has a journal housing rotatably attached to a housing of the crusher, and a roller portion formed of a metal material that actually contacts and presses the object to be crushed. are doing. The journal housing and the roller portion are fitted by shrink fitting, and when the roller portion is worn, the roller portion is removed to enable maintenance (for example, pulverized coal described in Patent Document 1). Machine roller).

Japanese Patent No. 5259162

By the way, recently, as a pulverizing roller used in a pulverizer, a pulverizing roller having a roller part having a hardened part on its surface, and furthermore, a ceramic is applied to the surface of a roller part made of high chromium cast iron having excellent wear resistance. An embedded ceramic embedded casting roller may be used. The ceramic embedded casting roller can grind the object to be crushed not only with the ceramic part on the surface but also with the high chromium cast iron as the base material, so the allowable wear amount is greatly increased and the life of the grinding roller can be extended. it can.

However, in the ceramic embedded casting roller, the thermal expansion coefficient of the hardened portion provided on the surface of the roller portion (particularly, the ceramic embedded in the hardened portion) is different from that of the high chromium cast iron base material. For this reason, when the roller portion and the base material are assembled by shrink fitting like the pulverized coal machine roller of Patent Document 1, when the temperature of the roller portion rises due to the difference in thermal expansion coefficient, the hardened portion of the surface is hardened. (Especially, the ceramic part) may be damaged, so the assembly by gap fitting has been the mainstream. In order to perform this gap fitting, in addition to the dimensional control of the fitting portion between the journal housing and the roller portion, it is necessary to attach and fix the fixing member, which has been a factor for increasing the remodeling cost and the number of man-hours for maintenance work. .

The present invention has been made in view of such circumstances, and a method of manufacturing a crushing roller capable of making it difficult to damage a hardened portion by making it difficult for a crack to propagate to the hardened portion during shrink fitting. And a heating device.

In order to solve the above-mentioned problems, a method for manufacturing a pulverizing roller and a temperature raising device according to the present invention employ the following means.
A method of manufacturing a crushing roller according to one embodiment of the present invention is used for a crusher that crushes an object to be crushed, and a support portion rotatably supported with respect to a housing of the crusher, an annular base, and an annular base. An annular roller portion provided on a radially outer peripheral surface of the base portion and having a hardened portion having a different coefficient of thermal expansion from the base portion, wherein the center axis of the roller portion is a floor. Heating in which the roller portion is heated from the radially outer peripheral surface side of the roller portion in a state in which the roller portion is in a direction orthogonal to the surface and the radially inner peripheral surface of the roller portion is open to the outside air. And an arrangement step of arranging the support section and the roller section in a state where the temperature is increased by the heating step, such that the inner peripheral surface of the roller section faces or contacts the outer peripheral surface of the support section. The above-mentioned b arranged in the above-mentioned arranging step. La portion is cooled, and a, a fitting step of fitting the said support portion and the roller portion.

In the above configuration, the roller and the support are fitted by so-called shrink fitting in which the heated roller is cooled and fitted to the support.

Further, in the above configuration, in the heating step, the roller portion is heated from the outer peripheral surface side in a state where the inner peripheral surface of the roller portion is open to the outside air. For this reason, the temperature of the outer peripheral surface side of the roller portion rises faster than that of the inner peripheral surface side, and becomes higher than that of the inner peripheral surface side. Thereby, the base of the roller portion thermally expands outward in the radial direction (that is, so as to increase the outer shape). On the other hand, the cured portion has a different thermal expansion coefficient from that of the base portion, and therefore has a smaller thermal expansion amount than the base portion or has a larger thermal expansion amount than the base portion. Therefore, when the roller portion thermally expands outward in the radial direction, a pressing force acts on the hardened portion in the radial direction by being restrained by the base portion. Therefore, a compressive stress in the radial direction is generated in the hardened portion. As described above, in the heating step of heating the roller portion, the stress generated in the hardened portion can be mainly used as the compressive stress, so that the tensile stress generated in the hardened portion is suppressed, and the crack propagates to the hardened portion. It can be difficult. Therefore, the hardened portion can be hardly damaged.

Further, since the roller portion and the support portion can be fitted by shrink fitting as described above, even if the grinding roller has a hardened portion on the outer peripheral surface, special processing is performed on the roller portion and the support portion. Thus, the crushing roller can be manufactured by fitting the roller portion and the support portion together. Therefore, the cost can be reduced and the time required for manufacturing can be reduced as compared with a method of performing special processing on the roller portion and the support portion.

Further, the roller unit is installed in a state where the center axis of the roller unit is orthogonal to the floor surface, and the inner peripheral surface is open to the outside air (in other words, the state where it is open to the atmosphere). Heating. As a result, the air in a space (hereinafter, referred to as an “inner space”) formed inside the inner peripheral surface of the annular roller portion rises in temperature by heating, and becomes a rising airflow due to a chimney effect and is released to the atmosphere. Is done. Therefore, since the heated air does not stay in the inner space, the expansion of the temperature distribution on the inner peripheral surface of the roller portion can be suppressed, and the generation of uneven stress in the entire roller portion can be suppressed. Therefore, the roller portion can be hardly damaged. The damage to the roller portion includes, for example, generation of partial micro-cracks, growth of internal cracks, and partial drop-off.

(4) Since the inner peripheral surface of the roller unit is open to the outside air in the step of heating the roller unit, the inner peripheral surface of the roller unit can be accessed in the heating step. Thus, in the heating step, the amount of thermal expansion of the inner diameter of the roller portion can be measured with a caliper, a laser distance measuring device, or the like. Therefore, the heating can be performed while checking the thermal expansion amount of the inner diameter of the roller portion, so that the desired thermal expansion amount can be reliably obtained. In addition, since the amount of thermal elongation is continuously checked, the heating process can be completed when the desired amount of thermal elongation is reached. Can be shortened.

In addition, in the method for manufacturing a pulverizing roller according to one aspect of the present invention, the hardening unit may include at least a part of a member having a smaller coefficient of thermal expansion than the base.

In the above configuration, the hardened portion at least partially includes a base and a member having a small coefficient of thermal expansion, for example, a ceramic. When the hardened part expands outward in the radial direction, a pressing force acts on the hardened part and a radial compressive stress is generated, so even if there is a member with less thermal expansion than the base, it is generated in the hardened part Due to the compressive stress, it is possible to make it difficult for cracks to propagate in a member having a small coefficient of thermal expansion in the hardened portion, for example, ceramics. Therefore, the hardened portion can be hardly damaged.

Further, in the method of manufacturing a crushing roller according to one aspect of the present invention, in the heating step, a lower space is formed between the roller portion and the floor surface, and the inner space of the lower space and the roller portion is formed. The roller unit may be heated in a state where the inner space formed inside the surface communicates with the roller unit.

では In the above configuration, the lower space formed between the roller portion and the floor surface communicates with the inner space. This allows air to flow from below the inner space through the lower space, so that the chimney effect can be more effectively applied and an ascending airflow can be reliably generated in the inner space. Therefore, more preferably, the temperature distribution on the inner peripheral surface of the roller can be suppressed, and the occurrence of uneven stress in the entire roller portion can be suppressed.

In the method of manufacturing a crushing roller according to one aspect of the present invention, in the heating step, a radial outer peripheral surface of the roller unit is covered with a heater, and a radial outer peripheral surface of the heater is covered with a heat insulating material. In this state, the roller unit may be heated by raising the temperature of the heater.

In the above configuration, since the outer peripheral surface of the heater is covered with the heat insulating material, heat dissipation from the heater can be reduced, and the heat flux from the heater to the roller unit can be stabilized. Therefore, the distribution of the amount of heat transfer from the heater to the outer peripheral surface of the roller portion can be suppressed and uniformized.
In addition, since the inner peripheral surface of the roller portion is open to the atmosphere (that is, the low temperature side), heat input from the outer peripheral surface easily moves toward the inner peripheral surface. In this manner, the direction of the heat flux toward the inner peripheral surface side can be directed, so that the temperature rise on the inner peripheral surface side of the roller portion can be stabilized.

In the method of manufacturing a pulverizing roller according to one aspect of the present invention, in the heating step, the roller unit may be heated while the heater is heated from a room temperature state at a predetermined heating rate.

熱 It takes a certain time for the heat input from the outer peripheral surface to transfer to the inner peripheral surface. For this reason, when the roller portion is heated from the outer peripheral surface by the heater, a temperature difference occurs between the outer peripheral surface and the inner peripheral surface. In the above configuration, the roller unit is heated while the heater is heated at a predetermined temperature rising rate from the room temperature state. As a result, the outer peripheral surface and the inner peripheral surface of the roller section also rise in temperature so as to follow the temperature rise of the heater. Therefore, the temperature difference between the inner peripheral surface and the outer peripheral surface of the roller portion is smaller than that of a method in which the heater that maintains the temperature at a constant value and heats the outer peripheral surface of the roller portion at a constant temperature. Therefore, it is possible to reduce the stress generated in the hardened portion provided on the outer peripheral surface side of the roller portion. Therefore, the roller portion can be hardly damaged.

In addition, in the method for manufacturing a pulverizing roller according to one aspect of the present invention, the predetermined heating rate may be 1 ° C / min or more and 2 ° C / min or less.

If the heating rate of the heater is reduced, the temperature difference between the inner peripheral surface and the outer peripheral surface of the roller portion can be sufficiently reduced and the roller portion can be hardly damaged, but the roller portion and the support portion are shrink-fitted. Therefore, it takes time to obtain the necessary thermal elongation, so that the heating step is lengthened and the workability is reduced. On the other hand, if the heating rate of the heater is increased, the heating process can be shortened, but the temperature difference between the inner peripheral surface and the outer peripheral surface of the roller unit cannot be sufficiently reduced, so that the roller unit cannot be heated. Damage is more likely to occur.

In the above configuration, the temperature of the heater is raised at a rate of 1 ° C./min or more and 2 ° C./min or less. By setting the heating rate to 2 ° C./min or less in this manner, the temperature difference between the inner peripheral surface and the outer peripheral surface of the roller portion can be sufficiently reduced, and the roller portion can be hardly damaged. By setting the temperature rate to 1 ° C./min or more, it is possible to prevent an excessively long heating step and improve workability.

In the method of manufacturing a grinding roller according to one aspect of the present invention, in the heating step, a metal foil may be provided between the roller unit and the heater.

In the above configuration, a metal foil is provided between the roller section and the heater. Since the metal foil is easily deformed and has high thermal conductivity, the metal foil provided between the roller portion and the heater is deformed into a shape corresponding to the gap between the roller portion and the heater, and the roller is deformed. The contact thermal resistance is reduced by making close contact with the section and the heater. As described above, by providing the metal foil between the roller portion and the heater, the gap formed between the roller portion and the heater can be filled with the metal foil.
Since the metal foil has good thermal conductivity, filling the gap formed between the roller and the heater with the metal foil improves the thermal conductivity between the roller and the heater. Thereby, the heat flux from the heater to the roller unit can be increased. Therefore, the heat of the heater is easily transmitted to the inner peripheral surface of the roller portion, and thus the temperature on the inner peripheral surface is suitably increased. Therefore, the temperature distribution on the inner peripheral surface of the roller portion can be suppressed, and the occurrence of uneven stress in the entire roller portion can be suppressed. Therefore, the roller portion can be hardly damaged.
In addition, as a metal foil, an aluminum foil is mentioned, for example.

Further, in the method of manufacturing a crushing roller according to one aspect of the present invention, in the heating step, the heating of the roller unit is performed by increasing the temperature of the heater at a first temperature increasing rate until a predetermined time has elapsed from the start of heating. A first heating step to be performed, and a second heating step of heating the roller unit by heating the heater at a second heating rate higher than the first heating rate after the first heating step. And a step.

In the above configuration, the roller unit is heated by increasing the temperature of the heater at the first temperature increasing rate until a predetermined time has elapsed from the start of heating. Thus, it is possible to suppress an increase in the temperature difference between the outer peripheral surface and the inner peripheral surface of the roller portion, which is caused by a sharp rise in temperature on the outer peripheral surface of the roller portion with the start of heating. Therefore, it is possible to reduce the stress generated in the hardened portion provided on the outer peripheral surface side of the roller portion. Therefore, the roller portion can be hardly damaged.

Further, in the method of manufacturing the pulverizing roller according to one aspect of the present invention, the plurality of heaters are provided, and the plurality of heaters are arranged in a circumferential direction so as to be along the outer peripheral surface of the roller unit. In addition, the heating rate may be controlled by different heating rate control units.

In the above configuration, a plurality of heaters that cover the outer peripheral surface of the roller unit are arranged side by side, and the heating rates are controlled by different heating rate controllers. Thus, by appropriately controlling the heating rate of each heater individually, it is possible to suppress the occurrence of temperature distribution on the outer peripheral surface of the roller unit even in the case of a large roller unit. By suppressing the occurrence of the temperature distribution on the outer peripheral surface, the heat input from the outer peripheral surface can be made uniform, so that the temperature distribution on the inner peripheral surface of the roller portion can be suppressed.

(4) Since a plurality of heaters covering the outer peripheral surface of the roller portion are arranged side by side, each heater is downsized. Thus, the temperature distribution in each heater can be reduced, so that the occurrence of a temperature distribution on the outer peripheral surface of the roller unit can be suppressed.

Further, in the method for manufacturing a pulverizing roller according to one aspect of the present invention, a heating rate storing step of storing a heating rate of the heater in the heating step; and a thermal elongation of the roller unit in the heating step. A thermal elongation amount storing step of storing the amount, a heating rate stored in the heating rate storing step, and a thermal elongation amount stored based on the thermal elongation amount stored in the thermal elongation amount storing step. And a table creation step of creating a table that defines the relationship between the roller section and the preliminary heating of the roller portion at a temporary heating rate, and the temporary heating rate and the preliminary heating. The heating of the roller unit may be performed at a temperature increasing rate determined based on the amount of thermal expansion of the roller unit and the table.

In the above configuration, the appropriate heating rate of the roller section is determined by determining the appropriate heating rate of the heat treatment of the roller section by performing preliminary heating in which the roller section is heated at a temporary heating rate at the site where the pulverizer is located. The heating can be performed within the range described above.
Further, the determined heating rate can be achieved under conditions where the temperature difference due to the rapid temperature gradient between the inner surface of the roller and the outer surface of the roller does not increase, so that the stress applied to the hardened portion provided on the outer peripheral surface of the roller portion can be reduced. This is preferable because generation can be suppressed and partial damage can be suppressed.

A temperature raising device according to one embodiment of the present invention is used for a crusher that crushes an object to be crushed, is provided on an annular base and a radially outer peripheral surface of the base, and has a different coefficient of thermal expansion than the base. What is claimed is: 1. A temperature raising device for raising the temperature of an annular roller portion having a hardening portion, comprising: a heater provided to cover a radially outer peripheral surface of the roller portion; and controlling a temperature rising speed of the heater. A heating rate control unit, wherein the heating rate control unit controls the heater so that the heating rate is 1 ° C./min or more and 2 ° C./min or less.
Further, in the temperature raising device according to an aspect of the present invention, the heater is disposed in a state where a central axis is in a direction orthogonal to a floor surface, and a radial inner peripheral surface of the roller unit is open to the outside air. It may be provided for the roller portion arranged in a state where it is set.

If the heating rate of the heater is reduced, the temperature difference between the inner peripheral surface and the outer peripheral surface of the roller portion can be sufficiently reduced and the roller portion can be hardly damaged, but the roller portion and the support portion are shrink-fitted. Therefore, it takes a long time to obtain a necessary amount of thermal elongation, so that the heating step is lengthened. On the other hand, if the heating rate of the heater is increased, the heating process can be shortened, but the temperature difference between the inner peripheral surface and the outer peripheral surface of the roller unit cannot be sufficiently reduced, so that the roller unit cannot be heated. Damage is more likely to occur.

In the above configuration, the temperature of the heater is raised at a rate of 1 ° C./min or more and 2 ° C./min or less. By setting the heating rate to 2 ° C./min or less in this manner, the temperature difference between the inner peripheral surface and the outer peripheral surface of the roller portion can be sufficiently reduced, and the roller portion can be hardly damaged. By setting the temperature rate to 1 ° C./min or more, an excessively long heating step can be suppressed and workability can be improved.

Further, in the temperature raising device according to an aspect of the present invention, a plurality of the heaters are provided, a plurality of the temperature raising speed control units are provided, and a plurality of the heaters have the radius of the roller unit. May be arranged in the circumferential direction so as to be along the outer peripheral surface in the direction, and the heating rate may be controlled by different heating rate control units.

In the above configuration, a plurality of heaters that cover the outer peripheral surface of the roller unit are arranged side by side, and the heating rates are controlled by different heating rate controllers. Thus, by appropriately controlling the heating rate of each heater individually, it is possible to suppress the occurrence of a temperature distribution on the outer peripheral surface of the roller unit even if the roller unit becomes large. By suppressing the occurrence of the temperature distribution on the outer peripheral surface, the heat input from the outer peripheral surface can be made uniform, so that the temperature distribution on the inner peripheral surface of the roller portion can be suppressed.

According to the present invention, it is possible to make it difficult for the crack to propagate to the hardened portion during shrink fitting, so that the hardened portion is hardly damaged.

It is a longitudinal section showing the schematic structure of the solid fuel crushing device to which the crush roller manufactured by the manufacturing method of the crush roller concerning the embodiment of the present invention is applied. FIG. 2 is a perspective view of the crushing roller of FIG. 1. It is a longitudinal cross-sectional view of the grinding roller of FIG. It is a typical longitudinal section of a grinding roller for explaining a heating process of a manufacturing method of a grinding roller concerning this embodiment. It is a schematic diagram which shows the outline of the temperature raising apparatus which concerns on this embodiment. 6 is a graph showing changes in the temperature of the heater, the temperature of the inner surface of the roller, and the temperature difference between the inner surface of the roller and the outer surface of the roller portion with elapsed time. FIG. 9 is a graph showing changes in the temperature of the heater, the temperature of the inner surface of the roller, the temperature difference between the inner surface of the roller and the outer surface of the roller, and the amount of thermal elongation of the inner diameter with the lapse of time when the heater is heated at a heating rate of 10 ° C./30 minutes. is there. FIG. 6 is a graph showing changes in the temperature of the heater, the temperature of the inner surface of the roller, the temperature difference between the inner surface of the roller and the outer surface of the roller, and the amount of thermal elongation of the inner diameter with the lapse of time when the heater is heated at a heating rate of 50 ° C./30 minutes. is there. FIG. 5 is a graph showing changes in the temperature of the heater, the temperature of the inner surface of the roller, the temperature difference between the inner surface of the roller and the outer surface of the roller, and the amount of thermal expansion of the inner diameter with the lapse of time when the heater is heated at a heating rate of 90 ° C./30 minutes. is there. 4 is a graph showing a relationship between a heating rate of a heater and a time required to reach a required thermal elongation, and a relationship between a heating rate of the heater and a roller inner surface temperature. 4 is a graph showing a relationship between a heater temperature and a roller inner surface temperature. 5 is a graph showing a relationship between elapsed time and a temperature difference between a heater temperature or a roller outer surface temperature and a roller inner surface temperature. 6 is a graph showing changes in the temperature of the heater, the temperature of the roller inner surface, and the temperature difference between the roller inner surface and the roller outer surface with elapsed time.

Hereinafter, an embodiment of a method of manufacturing a crushing roller and a temperature raising device according to the present invention will be described with reference to the drawings.
The crushing roller 5 manufactured by the crushing roller manufacturing method according to the present embodiment can be used, for example, as the crushing roller 5 applied to the crusher 1 described below.
In the present embodiment, “upward” indicates a vertically upward direction, and “upper” such as an upper portion or an upper surface indicates a vertically upward portion. Similarly, “below” indicates a vertically lower portion. The outer peripheral surface and the inner peripheral surface indicate the outer periphery and the inner periphery in the radial direction from the center axis of the annular roller portion 24.

As shown in FIG. 1, a crusher 1 includes a hollow cylindrical housing 2 forming an outer shell, and an air supply duct 3 communicating with a lower side surface of the housing 2 and supplying a carrier gas into the housing 2. Prepare. Inside the housing 2, a crushing table 4 rotatably supported on the housing 2 about a rotation axis along a vertical vertical direction, and an object to be crushed on the crushing table 4 (in the present embodiment, as an example, A pulverizing roller 5 for pulverizing a solid fuel such as coal) is accommodated.

The housing 2 has a cylindrical shape, and a tubular fuel supply pipe 7 is provided at the upper center so as to penetrate the ceiling surface 2b. The fuel supply pipe 7 supplies solid fuel such as coal into the housing 2 from a solid fuel supply device (not shown), and extends vertically at the center of the housing 2. In addition, a rotary separator 8 that rotates around the fuel supply pipe 7 in the housing 2 and exists in a direction orthogonal to the longitudinal direction of the fuel supply pipe 7 is provided. The rotary separator 8 classifies the pulverized solid fuel (hereinafter, the pulverized solid fuel is referred to as “pulverized fuel”) based on a predetermined particle size. An outlet port 9 is provided in the ceiling surface 2 b of the housing 2, which is a carry-out port for conveying the pulverized fuel having a predetermined particle size or less classified by the rotary separator 8 to a downstream device.

The crushing table 4 has a rotation support portion 15 rotatably supported at substantially the center of the bottom surface portion 2c of the housing 2, and a substantially circular plate-shaped table portion 16 fixed to the upper end of the rotation support portion 15. The rotation support unit 15 is rotationally driven by a driving device (not shown). The table portion 16 is arranged to face the lower end portion on the vertically lower side of the fuel supply pipe 7, and rotates together with the rotation support portion 15. The upper surface of the crushing table 4 has an inclined shape that extends in the horizontal direction, the height of the center portion is vertically higher than the outside, and the height decreases from the center to the outside. , The outer peripheral portion is curved upward again.

The air supply duct 3 is provided so as to extend substantially parallel to the horizontal plane, and communicates with the side surface 2 a of the housing 2. The air supply duct 3 supplies a carrier gas supplied from an air supply device (not shown) into the housing 2. The carrier gas supplied from the air supply duct 3 is interposed between the crushing table 4 and the crushing roller 5 on the crushing table 4 to pneumatically transport the crushed fine fuel to the rotary separator 8.

A plurality (three in the present embodiment, for example) of the crushing rollers 5 are arranged vertically above the outer peripheral portion of the table 16 so as to face the table 16. Note that, in FIG. 1, only one of the plurality of crushing rollers 5 is illustrated for the sake of illustration. The plurality of crushing rollers 5 are arranged at equal intervals in the circumferential direction. For example, three crushing rollers 5 are equally spaced in the circumferential direction at an angular interval of 120 ° on the outer peripheral portion. The detailed description of the crushing roller 5 will be described later.
Each grinding roller 5 is fixed to the housing 2 via a journal shaft 17, a journal head 18 and an eccentric shaft 19 (see also FIGS. 2 and 3). The journal shaft 17 extends from the side surface portion 2a of the housing 2 toward the center portion so as to be inclined vertically downward, and the tip end portion rotatably supports the grinding roller 5 via a bearing (not shown). That is, the crushing roller 5 is rotatably supported vertically above the crushing table 4 in an inclined state in which the upper side is located closer to the center of the housing 2 than the lower side.

The journal head 18 is supported on the side surface 2a of the housing 2 so as to be vertically swingable by an eccentric shaft 19 having a middle portion extending in the horizontal direction. The journal head 18 supports the base end of the journal shaft 17 to which the grinding roller 5 is rotatably mounted at the tip. That is, the crushing roller 5 is supported so as to be detachable from the upper surface of the crushing table 4 by the journal head 18 swinging vertically about the eccentric shaft 19 as a fulcrum.

押圧 A pressing device 20 is provided at an upper end vertically above the journal head 18, and a stopper 21 is provided at a lower end of the journal head 18. The pressing device 20 is fixed to the housing 2 and applies a downward load to the pulverizing roller 5 via the journal head 18 or the like to pulverize the solid fuel supplied on the pulverizing table 4. The stopper 21 is fixed to the housing 2 and regulates the amount by which the crushing roller 5 can rotate vertically downward, and adjusts the gap between the crushing roller 5 and the crushing table 4.

Next, details of the crushing roller 5 will be described with reference to FIGS.
The crushing roller 5 includes a journal housing (supporting portion) 23 rotatably supported by a tip end portion of the journal shaft 17, and an annular roller portion 24 which is fitted on the journal housing 23. The journal housing 23 is provided so as to cover the tip of the journal shaft 17, and has a cylindrical outer peripheral surface.

In the present embodiment, as shown in FIG. 3, the roller portion 24 partially includes a base portion 25 made of high chromium cast iron fitted to the journal housing 23 and a ceramic member provided on the outer peripheral surface of the base portion 25. And a curing unit 26. That is, the roller section 24 according to the present embodiment is a so-called ceramic embedded high chromium cast iron roller. The base 25 is formed in a substantially annular shape. Further, the base 25 is fitted to the journal housing 23 such that the inner peripheral surface is in contact with the outer peripheral surface of the journal housing 23. The hardened portion 26 is fixed so as to be embedded over substantially the entire circumferential surface of the outer peripheral surface of the annular base 25. Further, since the hardened portion 26 is made of ceramic, it has a smaller coefficient of thermal expansion than the base 25 made of high chromium cast iron.
In the present embodiment, the outer diameter L1 of the roller portion 24 is, for example, about 1 m to about 2 m, and the length L2 in the central axis direction of the roller section 24 is, for example, about 0.3 m to about 0.7 m. 24 has a radial length L3 of, for example, about 0.1 m to about 0.3 m. That is, the inner diameter L4 of the roller portion 24 is from about 0.5 m to about 1.8 m (see FIG. 4).

Next, a method of fitting the journal housing 23 and the roller portion 24 in the method of manufacturing the crushing roller 5 will be described.
In the present embodiment, the inner diameter of the inner peripheral surface of the roller portion 24 is increased by heating the roller portion 24 from the outer peripheral surface side in the radial direction (thermal process), and the inner diameter is increased by heating. The journal housing 23 is positioned in a space (hereinafter, referred to as “inside space”) formed inside the inner peripheral surface of the roller portion 24 in the state (arrangement step), and then the roller portion 24 is cooled to cool the roller portion. The journal housing 23 and the roller portion 24 are fitted by reducing the inner diameter of the 24 (fitting step). That is, the journal housing 23 and the roller portion 24 are fitted by so-called shrink fitting. In the arranging step, the roller unit 24 is arranged so that the inner peripheral surface thereof faces or contacts the outer peripheral surface of the journal housing 23.

The heating step will be described in detail.
In the heating step, first, as shown in FIG. 4, the roller unit 24 is disposed on a base on the floor surface formed of the insulating bricks 27 so that the central axis C1 is in a direction orthogonal to the floor surface. In other words, the roller unit 24 is arranged such that the circular surface is placed and is horizontal with respect to the floor surface. The base has a height of 50 mm to 200 mm and is provided so that a lower space is formed between the roller portion 24 and the ground. The heat-insulating bricks 27 forming the base are arranged such that the lower space communicates with the inner space of the roller portion 24. The arrows in FIG. 4 indicate a situation in which the air in the inner space is heated by the temperature difference with the inner peripheral surface of the roller portion 24 and rises in temperature.

The outer peripheral surface of the roller portion 24 is substantially entirely covered by a plurality of heaters 31 provided along the outer peripheral surface. When the heater 31 is installed on the outer peripheral surface of the roller portion 24, it is desirable that the heater 31 be in close contact with the outer peripheral surface of the roller portion 24 as uniformly as possible. The outer peripheral surface is fixed at a plurality of locations in the vertical direction with wires or the like without rattling. The entire outer peripheral surface of the heater 31 is covered with a heat insulating material 29 provided along the outer peripheral surface.
The inner peripheral surface of the roller portion 24 is not covered with the heater 31, the heat insulating material 29, and the like, and is in a state of being opened to the outside air (that is, a state of being opened to the atmosphere).

(4) In the heating step, the heater 31 is heated at a predetermined heating rate from the room temperature state to the roller unit 24 in the room temperature state thus arranged.

Next, a temperature raising device 30 for heating the roller unit 24 in the heating step will be described with reference to FIG.
As shown in FIG. 5, the temperature raising device 30 includes a plurality of (in the present embodiment, three as an example, three) heaters 31 arranged in the circumferential direction along the outer peripheral surface of the roller portion 24, A plurality (three in the present embodiment, for example, three) of power supply control units (heating rate control units) 32 for controlling the amount of power supply to the heater 31, and a power supply unit 33 for supplying electricity to each power supply control unit 32 , A temperature measuring device 34 for measuring the temperature of the outer peripheral surface of the roller portion 24.

Each heater 31 is, for example, a planar heater 31 having flexibility that can be in close contact with the outer peripheral surface of the roller unit 24 such as an Almat heater or a ribbon heater. Each heater 31 is arranged so as to cover a region obtained by equally dividing the outer peripheral surface of the roller portion 24 in the circumferential direction. That is, three substantially identical heaters 31 cover substantially the entire outer peripheral surface of the roller portion 24.

The temperature measuring device 34 is provided one by one in the area where each heater 31 is provided on the outer peripheral surface of the roller section 24, and measures the temperature of the outer peripheral surface of the roller section 24 in the provided area. The temperature measuring device 34 transmits the measured temperature to the power supply control unit 32. The temperature measuring device 34 may be any device that can measure the temperature, for example, a thermocouple.

As described above, three power supply control units 32 are provided, and each of the three power supply control units 32 controls a heating rate of the heater 31 by controlling a power supply amount to a different heater 31. . That is, the three power supply control units 32 and the three heaters 31 are in one-to-one correspondence. Each power supply control unit 32 may adjust the amount of power supplied to each heater 31 based on the temperature measured by the temperature measuring device 34 so that the temperature measured by each temperature measuring device 34 is substantially the same. Good.

The power supply control unit 32 includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a computer-readable storage medium. For example, a series of processes for realizing various functions are stored in a storage medium or the like in the form of a program as an example, and the CPU reads the program into a RAM or the like, and executes information processing and arithmetic processing. Thereby, various functions are realized. The program may be installed in a ROM or other storage medium in advance, provided in a state stored in a computer-readable storage medium, or delivered via a wired or wireless communication unit. Etc. may be applied. The computer-readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.

The numbers of the heaters 31, the power supply control units 32, and the temperature measuring devices 34 are not limited to the above examples. It may be singular or plural other than three.

Next, a method of heating the roller unit 24 performed by the temperature raising device 30 in the heating step will be described.
In the heating step according to the present embodiment, the roller unit 24 is heated while the heater 31 of the temperature raising device 30 is heated at a predetermined temperature rising rate. Specifically, the roller unit 24 is heated by increasing the temperature of the heater 31 at a rate of 1 ° C./min or more and 2 ° C./min or less. As described above, in the present embodiment, by heating the roller unit 24 while increasing the temperature of the heater 31 at a predetermined heating rate, the temperature of the outer peripheral surface of the roller unit 24 and the inner peripheral surface of the roller unit 24 are increased in the temperature of the heater 31. Follows the temperature.

On the other hand, as a method of heating the roller unit 24 using the heater 31, a method of heating the roller unit 24 with the heater 31 maintaining a constant temperature is also conceivable. However, when the roller portion 24 is heated by the heater 31 maintaining the constant temperature, the temperature of the outer peripheral surface of the roller portion 24 is maintained at a substantially constant temperature slightly lower than the temperature of the heater 31, but the inner peripheral portion of the roller portion 24 is maintained. It has been found that the temperature difference between the surface and the outer peripheral surface increases, and there is a possibility that the roller portion 24 may be damaged. In addition, the method of heating the roller unit 24 while heating the heater 31 at a predetermined heating rate is more effective than the method of heating the roller unit 24 with the heater 31 maintaining a constant temperature. It has been found that the temperature difference between the outer peripheral surface and the outer peripheral surface can be reduced, and the stress generated in the hardened portion 26 provided on the outer peripheral surface of the roller portion 24 can be reduced.

The reduction in the temperature difference between the inner peripheral surface and the outer peripheral surface of the roller portion 24 will be described in detail with reference to the graph of FIG. FIG. 6 shows the temperature of the heater 31, the temperature of the inner peripheral surface of the roller portion 24 (hereinafter, also referred to as “roller inner surface”), and the outer peripheral surfaces of the roller inner surface and the roller portion 24 (hereinafter, also referred to as “roller outer surface”). 5 is a graph showing a change in the temperature difference with the elapsed time, with the horizontal axis indicating the elapsed time (minutes) and the vertical axis indicating the temperature difference ΔT (° C.) or the temperature (° C.).
The solid line 61 in FIG. 6 indicates the temperature of the heater 31 when the temperature of the heater 31 is kept constant at 200 ° C. The solid line 62 indicates the roller inner surface temperature when the temperature of the heater 31 is kept constant at 200 ° C., and the solid line 63 indicates the temperature difference between the roller inner surface and the roller outer surface in this case. A broken line 64 in FIG. 6 indicates the temperature of the heater 31 when the temperature of the heater 31 is increased at a rate of 50 ° C./30 minutes. A broken line 65 indicates the roller inner surface temperature when the temperature of the heater 31 is increased at a heating rate of 50 ° C./30 minutes, and a broken line 66 indicates a temperature difference between the roller inner surface and the roller outer surface in this case. ing.

The roller inner surface temperature T in FIG. 6 is calculated by the following equation (1).
(T−Ta) / (To−Ta) = Exp (−hA / (CM) × τ) (1)
However, T: the unsteady temperature of the inner surface of the roller To: the initial temperature of the inner surface of the roller (for example, this time, the room temperature is 25 ° C.)
Ta: heating side temperature (that is, heater 31 temperature this time)
C: Specific heat of the roller (for example, 0.5 to 0.6 kJ / kg ° C)
h: Heat conductivity from the heater 31 to the inside of the roller (for example, 1 to 50 W / m ² K)
τ: time M: mass of the roller A: area of the roller ρ: density of the roller t: heat conduction distance of the roller Here, since M = Aρt, the above equation (1) becomes the following equation (2).
(T−Ta) / (To−Ta) = Exp (−h / (Cρt) × τ) (2)

Comparing the solid line 63 and the dashed line 66 shown in FIG. 6, the roller 31 is heated while the temperature of the heater 31 is kept constant at all times. It can be seen that the temperature difference between the heater heating surface (that is, the roller outer surface) and the roller inner surface is smaller when the portion 24 is heated. For example, during the elapsed time of 20 minutes to 40 minutes, the temperature difference between the heater heating surface (that is, the outer surface of the roller) and the inner surface of the roller is smaller than when the roller portion 24 is heated while the temperature of the heater 31 is kept constant. It can be seen from FIG. 6 that the case where the roller portion 24 is heated while the temperature of the heater 31 is increased can be suppressed to about 1/3 or less.

Next, a method of setting the temperature rising rate of the heater 31 will be described.
In this embodiment, the roller unit 24 is heated by increasing the temperature of the heater 31 at a rate of 1 ° C./min or more and 2 ° C./min or less. The temperature of the inner peripheral surface of the roller unit 24 is relatively low (for example, about 30 ° C. to 50 ° C.) by appropriately selecting the temperature rising rate of the heater 31 from the result of the heating test of the roller unit 24. ) Is set based on the finding that there is a roller heating condition capable of obtaining a thermal expansion amount of the inner diameter of the roller portion 24 that can be shrink-fitted. Hereinafter, a heating test of the roller unit 24 will be described with reference to FIGS.
In the present embodiment, when shrink-fitting the roller portion 24 and the journal housing 23, the roller portion 24 of the present embodiment has an inner diameter L4 of, for example, about 0.5 m to about 1.8 m. The amount of required thermal expansion in the radial direction of the inner diameter of the roller portion 24 is set to, for example, about 0.2 mm.

FIGS. 7 to 9 are graphs showing measured values of the temperature of the heater 31, the temperature of the inner surface of the roller, the temperature difference between the inner surface of the roller and the outer surface of the roller, and the change in the thermal expansion amount of the inner diameter with the lapse of time. The horizontal axis indicates elapsed time (minutes), and the vertical axis indicates the amount of thermal elongation (mm) and the temperature difference or temperature (° C.) of the inner diameter. The shaded portion indicates the elapsed time zone when the required thermal elongation reaches 0.2 mm. Each temperature and elapsed time is an example of the influence on the temperature rising rate of the heater 31, and is an example of the present embodiment.

FIG. 7 shows a case where the heater 31 is heated at a heating rate of 10 ° C./30 minutes. A solid line 71 is a heater temperature, a solid line 72 is a roller inner surface temperature, and a solid line 73 is a temperature difference between the roller inner surface and the roller outer surface. , The solid line 74 indicates the measured value of the thermal expansion amount of the inner diameter of the roller.

As shown in FIG. 7, when the rate of temperature rise of the heater 31 is relatively slow, it is necessary to heat the roller inner surface temperature from about 40 ° C. to about 45 ° C. in order to obtain the necessary thermal elongation, and the time is also from 115 minutes to 120 ° C. It takes about a minute. On the other hand, the temperature difference between the outer surface of the roller and the inner surface of the roller is as small as about 20 ° C. to 25 ° C., and the temperature of the entire roller unit 24 can be relatively uniformly increased.

FIG. 8 shows a case where the heater 31 is heated at a heating rate of 50 ° C./30 minutes. A broken line 81 indicates a heater temperature, a broken line 82 indicates a roller inner surface temperature, and a broken line 83 indicates a temperature difference between the roller inner surface and the roller outer surface. The broken line 84 indicates the measured value of the thermal expansion of the inner diameter of the roller.

As shown in FIG. 8, when the heating rate of the heater 31 is relatively high, the roller inner surface temperature rises almost 20 minutes after the start of the heating, and hardly rises (dashed line 82). reference). This is because the outer peripheral surface of the roller portion 24 thermally expands as the heating is advanced, and the thermal contact between the heater 31 and the outer peripheral surface of the roller portion 24 is improved.

熱 The amount of thermal expansion of the inner diameter of the roller portion 24 increases in proportion to the passage of time, including when the required amount of thermal expansion (0.2 mm) is reached after about 30 to about 35 minutes have elapsed. On the other hand, as described above, the roller inner surface temperature hardly rises for about 20 minutes from the start of heating. Thus, when the required thermal elongation is reached, the roller inner surface temperature is about 30 ° C. to 35 ° C. As described above, the reason why the required amount of thermal elongation is reached even though the roller inner surface temperature is relatively low is that the roller inner surface is subjected to tensile stress due to thermal expansion (thermal elongation) of the roller outer surface. Is due.

As described above, when the heater 31 is heated at a heating rate of 50 ° C./30 minutes, the required thermal elongation is at a relatively low level with the roller inner surface temperature. From this, it can be seen that, as described above, the tensile force due to the thermal expansion of the roller outer surface has begun to be generated on the roller inner surface.
The temperature difference between the inner surface of the roller and the outer surface of the roller is about 50 ° C. to 55 ° C. when the required thermal elongation (0.2 mm) is reached. Accordingly, it is considered that the compressive stress on the hardened portion 26 provided on the outer peripheral surface of the roller has begun to increase.

FIG. 9 shows a case where the heater 31 is heated at a heating rate of 90 ° C./30 minutes, where a dashed line 91 is a heater temperature, a dashed line 92 is a roller inner surface temperature, and a dashed line 93 is a roller inner surface and a roller outer surface. The dashed line 94 indicates the measured value of the thermal expansion amount of the roller inner diameter.

As shown in FIG. 9, when the heating rate of the heater 31 is even faster than that in the example of FIG. 8, the inner temperature of the roller hardly increases at the beginning of the heating, and the temperature rapidly increases after about 20 minutes. Since the temperature rises (see the dashed-dotted line 92) and reaches the required thermal elongation (0.2 mm) at this time, it is substantially difficult to control the temperature rise time. The cause of the rapid temperature rise is that the outer peripheral surface of the roller portion 24 thermally expands as the heating is advanced, and the thermal contact state between the heater 31 and the outer peripheral surface of the roller portion 24 improves, as in the example of FIG. It is. Further, the thermal expansion amount of the inner diameter of the roller portion 24 has reached the required thermal expansion amount (0.2 mm) after about 15 to about 20 minutes have elapsed, and the roller inner surface temperature at this time is almost the same as at the beginning of heating. The temperature remains unchanged at about 25 ° C. to 30 ° C.

The reason why the required amount of thermal elongation is reached despite the fact that the roller inner surface temperature hardly changes is that the roller inner surface is strongly subjected to tensile stress due to the thermal expansion (thermal elongation) of the roller outer surface. are doing. Therefore, the generation of stress exceeding the crack limit radial stress σo (in the present embodiment, about 40 N / mm ² is assumed in the case of the internal crack) on the roller portion 24 (particularly, the base portion 25). There is a concern that micro-cracks may occur in the roller portion 24 (particularly, on the outer peripheral side of the base portion 25).

(4) While the temperature rise on the inner surface of the roller stays at about 1 ° C. to 5 ° C., the temperature difference between the inner surface of the roller and the outer surface of the roller is as large as about 50 ° C. to 55 ° C. Thus, it is considered that the compressive stress on the hardened portion 26 provided on the outer peripheral surface of the roller has begun to further increase.

When the heater 31 is heated at a heating rate of 90 ° C./30 minutes as described above, the stress on the hardened portion 26 and the stress on the roller portion 24 (particularly, the outer peripheral side of the base portion 25) are increased. The risk of partial damage to the roller portion 24 increases.

Moreover, compared to other cases (examples shown in FIGS. 7 and 8), more power is required to be supplied to the heater 31, and a large power supply and equipment are required. In this embodiment, in order to raise the temperature of the heater 31 at a heating rate of 90 ° C./30 minutes, for example, a large power supply of 200 V and 40 A is required. To do so, this level of power capacity is at the upper limit. For this reason, it is difficult to raise the temperature more rapidly than this.

Thus, from FIGS. 7 to 9, it can be seen that when the rate of temperature rise of the heater 31 is increased, the required amount of thermal expansion can be obtained in a short time, but the risk of damage to the roller portion 24 increases.

{Circle around (2)} The relationship between the heating rate of the heater 31 and the risk of damage (particularly, the state of occurrence of tensile stress generated on the roller inner surface due to thermal expansion (thermal elongation) on the roller outer surface) will be described in more detail.

As described above, in the present embodiment, since the roller portion 24 is heated only from the outer peripheral surface side, when the thermal expansion amount (0.2 mm) required for shrink fitting is reached, “roller outer surface temperature> roller inner surface temperature” ", And the inner surface of the roller receives a tensile stress due to the thermal expansion (thermal expansion) of the outer surface of the roller.

Table 1 below shows that when the required amount of thermal elongation is reached, the roller inner surface temperature, heater temperature, arrival time, the amount of thermal elongation caused by the roller inner surface temperature, and the thermal expansion (thermal elongation) of the roller outer surface are generated on the inner surface of the roller. The state of occurrence of the tensile stress is shown for each heating rate of the heater 31. Note that, in the present embodiment, as described above, the crack limit radial stress σо is set to about 40 N / mm ² . The thermal expansion caused by the roller inner surface temperature is such that the Young's modulus E of the material of the base portion 25 of the roller portion 24 is 1.8 to 2.0 × 10 ⁵ N / mm ² and the linear expansion coefficient is 11 × 10 ⁻ It is calculated as ⁶ to 12 × 10 ⁻⁶ .

From Table 1, when the heating rate is 30 ° C./30 minutes to 90 ° C./30 minutes, when the required thermal elongation reaches 0.2 mm, the thermal elongation due to the roller inner surface temperature is Is 0.2 mm or less. That is, a value obtained by subtracting the thermal expansion caused by the roller inner surface temperature from 0.2 mm is pulled by the thermal expansion (thermal expansion) of the roller outer surface, and thus the length of the roller inner surface is extended.

Therefore, when the heating rate is 30 ° C./30 minutes to 90 ° C./30 minutes, the roller inner surface is pulled by the thermal expansion (thermal elongation) of the roller outer surface, and the roller inner surface is subjected to tensile stress. However, it can be seen that the longer the temperature rise rate, the longer the length of the roller inner surface that has been stretched by being pulled. In other words, it can be seen that the higher the heating rate, the greater the tensile stress applied to the inner surface of the roller.

引張 Further, the state of occurrence of tensile stress generated on the inner surface of the roller at each heating rate is as follows. When the heating rate was 30 ° C./30 minutes or 50 ° C./30 minutes, the tensile stress generated did not reach the crack limit radial stress σо. In addition, even when the heating rate is 60 ° C./30 minutes, the generated tensile stress does not reach the crack limit radial stress σо, and a tensile stress of about 80% of the crack limit radial stress σо is generated. I have. When the temperature rise rate is 90 ° C./30 minutes, the generated tensile stress has a value slightly smaller than the crack limit radial stress σо.

In consideration of the above results, when the heating rate is 90 ° C./30 minutes, it is feared that the tensile stress generated on the inner surface of the roller exceeds the crack limit radial direction stress σо, and the roller portion 24 is damaged. It is considered that the risk of the disease has increased. Therefore, it is understood that the upper limit of the heating rate of the heater 31 is preferably set to about 60 ° C./30 minutes (that is, 2 ° C./min).

Next, a method of setting the lower limit of the heating rate of the heater 31 will be described.
As can be seen from Table 1, the slower the heating rate, the longer the time to reach the required thermal elongation (0.2 mm).

粉砕 The crushing roller 5 may be replaced for the purpose of maintenance of the crushing roller 5 or the like. In order to install the replacement crushing roller 5, a temporary placement step of temporarily placing the replacement roller section, a heating step of heating the roller section 24, and a fitting step of fitting the roller section 24 and the journal housing 23 are performed. A step and an installation step of installing the crushing roller 5 in which the roller portion 24 and the journal housing 23 are fitted in the crusher 1 are required.

The time required in each step is, for example, as follows in the present embodiment. Note that the required time in the following description is merely an example, and the required time may be another time.
It takes about 5 minutes for the temporary placement step, about 10 minutes for the fitting step, and about 25 minutes for the installation step. That is, a total of about 40 minutes is required in other steps except the heating step. Therefore, assuming that the time of the heating step is Ht, the time required to replace one crushing roller 5 is Ht + 40 (minutes).

Next, a time suitable for replacing one crushing roller 5 is set as follows.
When two crushers 1 each having three crushing rollers 5 (six crushing rollers 5) are exchanged in one day as in the present embodiment, the working time per day is reduced by 10 days. In terms of time, the working time for one crushing roller 5 is determined to be 100 minutes from the following equation (3).
(10 × 60) minutes / 3 × 2 units ・・・ (3)

Therefore, from the following equation (4), it can be seen that the time Ht required for the heating step is desirably 60 minutes or less.
Ht + 40 minutes ≦ 100 minutes (4)

Considering the above results, Table 1 shows that it is preferable to set the lower limit of the heating rate of the heater 31 to about 30 ° C./30 minutes (that is, 1 ° C./min).

As described above, in the present embodiment, the lower limit of the heating rate of the heater 31 is set to 1 ° C./min from the viewpoint of workability, and the upper limit of the heating rate of the heater 31 is reduced from the risk of damage to the crushing roller 5. Is set to 2 ° C./min.
This will be described with reference to FIG. In FIG. 10, the relationship between the rate of temperature rise of the heater 31 (° C./min) and the time required to reach the required thermal elongation (0.2 mm) (minutes) is indicated by a broken line, and the rate of temperature rise of the heater 31 (° C./min) The relationship with the roller inner surface temperature (° C.) is shown by a solid line.

As shown by the dashed line in FIG. 10, if the heating rate of the heater 31 is 2 ° C./min or more, the roller inner surface temperature when the required amount of thermal elongation is reached becomes low, and the risk of damage increases, which is not suitable. Further, if the heating rate of the heater 31 is 1 ° C./min or less, the time required for the heating step becomes 60 minutes or more, and the workability deteriorates, which is not suitable. Therefore, the preferred range is 1 ° C./min to 2 ° C./min, which is the range indicated by the shaded arrow in FIG. In particular, from the viewpoint of both the risk of damage and the workability, the heating rate of 50 ° C./30 minutes shown by P in FIG. 10 is preferable.
It should be noted that a heating rate higher than 3 ° C./min is not appropriate because the required amount of thermal elongation is attained before the inner surface temperature of the roller is increased, and it is difficult to control the amount of thermal elongation.

According to the present embodiment, the following operation and effect can be obtained.
In the present embodiment, in the heating step, the roller portion 24 is heated from the outer peripheral surface side in the radial direction with the inner peripheral surface open to the outside air. Therefore, the temperature of the outer peripheral surface side of the base 25 rises faster than that of the inner peripheral surface side, and becomes higher than that of the inner peripheral surface side. As a result, the base portion 25 thermally expands outward in the radial direction (that is, so as to increase the outer shape). On the other hand, the hardened portion 26 has a different coefficient of thermal expansion from the base 25, and the hardened portion 26 may include a member having a low coefficient of thermal expansion, for example, ceramics. When the temperature of the hardened portion 26 is higher than that of the base portion 25, the amount of thermal expansion increases. Therefore, when the roller portion 24 thermally expands outward in the radial direction, the pressing portion acts on the hardened portion 26 in the radial direction while being restrained by the base portion 25. Therefore, a compressive stress in the radial direction is generated in the hardened portion 26. As described above, in the heating step of heating the roller portion 24, the stress generated in the hardened portion 26 can be mainly used as the compressive stress, so that the tensile stress generated in the hardened portion 26 is suppressed, and Cracks can be less likely to propagate. Therefore, the hardened portion 26 can be hardly damaged.

ローラ Further, the roller portion 24 and the journal housing 23 can be fitted by shrink fitting as described above. For this reason, there is no need to perform gap fitting, and even with the crushing roller 5 having the hardened portion 26 on the outer peripheral surface, the crushing roller 5 and the journal housing 23 can be fitted to the fixing member in addition to the dimensional management of the fitted portion. The crushing roller 5 can be manufactured by fitting the roller portion 24 and the journal housing 23 by shrink fitting without performing any special processing such as mounting processing. Therefore, the cost can be reduced and the time required for manufacturing can be reduced as compared with a method of performing special processing on the roller portion 24 and the journal housing 23.

In addition, the roller unit 24 is installed in a state where the central axis C1 is orthogonal to the floor surface and the inner peripheral surface is open to the outside air (in other words, the state where the inner peripheral surface is open to the atmosphere). The part 24 is being heated. As a result, the temperature of the air in the annular inner space rises by heating, and as a result of the chimney effect, as shown by an arrow in FIG. Therefore, since the heated air does not stay in the inner space, the temperature distribution on the inner peripheral surface of the roller portion 24 is suppressed to be reduced, and the occurrence of uneven stress in the entire roller portion 24 can be suppressed. . Therefore, the roller portion 24 can be hardly damaged. The damage to the roller portion 24 includes, for example, generation of a partial micro-crack, growth of an internal crack, and partial drop-off.

In the present embodiment, the lower space formed between the roller portion 24 and the floor surface and the inner space communicate with each other. This allows air to flow from below the inner space through the lower space, so that the chimney effect can be more effectively applied and an ascending airflow can be reliably generated in the inner space. Therefore, it is possible to more suitably suppress the temperature distribution on the inner peripheral surface of the roller and suppress the occurrence of uneven stress in the entire roller portion 24.

In addition, since the inner peripheral surface of the roller unit 24 is open to the outside air in the step of heating the roller unit 24, the inner peripheral surface of the roller unit 24 can be accessed in the heating step. Thus, in the heating step, the amount of thermal expansion of the inner diameter of the roller portion 24 can be measured with a caliper, a laser distance measuring device, or the like. Therefore, since the heating can be performed while checking the thermal expansion amount of the inner diameter of the roller portion 24, the desired thermal expansion amount can be reliably obtained. Therefore, since the amount of thermal elongation is continuously checked, the heating step can be completed when the desired amount of thermal elongation is reached. Can be optimized. In order to obtain a desired amount of thermal expansion of the inner diameter of the roller portion 24, the relationship between the heating time and the heating time when the heater 31 is set to a predetermined heating rate is confirmed by a preliminary test. The heating step may be managed.

In the present embodiment, since the radial outer peripheral surface of the roller portion 24 is covered with the heater 31 and the radial outer peripheral surface of the heater 31 is covered with the heat insulating material 29, heat dissipation from the heater 31 is reduced. The heat flux from 31 to the roller unit 24 can be stabilized. Therefore, the distribution of the amount of heat transfer from the heater 31 to the outer peripheral surface of the roller portion 24 can be suppressed and made uniform.
Further, since the inner peripheral surface of the roller portion 24 is open to the atmosphere (that is, the low-temperature side), heat input from the outer peripheral surface is likely to move toward the inner peripheral surface. In this manner, the direction of the heat flux toward the inner peripheral surface side can be directed, so that the temperature rise on the inner peripheral surface side of the roller portion 24 can be stabilized.

熱 It takes a certain time for the heat input from the outer peripheral surface to transfer to the inner peripheral surface. For this reason, when the roller portion 24 is heated from the outer peripheral surface by the heater 31, a temperature difference occurs between the outer peripheral surface and the inner peripheral surface. In the present embodiment, the roller unit 24 is heated while the temperature of the heater 31 is increased from a room temperature state at a predetermined heating rate. As a result, the outer peripheral surface and the inner peripheral surface of the roller portion 24 are also heated so as to follow the temperature rise of the heater 31. Therefore, the temperature difference between the inner peripheral surface and the outer peripheral surface of the roller portion 24 is smaller than that of a method in which the temperature of the outer peripheral surface of the roller portion 24 is kept constant by the heater 31 that keeps the temperature constant. . Therefore, stress generated in the hardened portion 26 provided on the outer peripheral surface side of the roller portion 24 can be reduced. Therefore, the roller portion 24 can be hardly damaged.

When the heating rate of the heater 31 is reduced, the temperature difference between the inner peripheral surface and the outer peripheral surface of the roller portion 24 can be sufficiently reduced and the roller portion 24 can be hardly damaged. Since it takes a long time to obtain the amount of thermal elongation necessary for shrink-fitting, the heating step is lengthened and the workability is reduced. On the other hand, if the heating rate of the heater 31 is increased, the heating process can be shortened, but the temperature difference between the inner peripheral surface and the outer peripheral surface of the roller portion 24 cannot be sufficiently reduced. The possibility that the part 24 will be damaged increases.

In the present embodiment, the temperature of the heater 31 is raised at a rate of 1 ° C./min or more and 2 ° C./min or less. As described above, by setting the heating rate to 2 ° C./min or less, the temperature difference between the inner peripheral surface and the outer peripheral surface of the roller portion 24 can be sufficiently reduced, and the roller portion 24 can be hardly damaged. By setting the heating rate to 1 ° C./min or more, the workability can be improved by preventing an excessively long heating step.

In the present embodiment, the plurality of heaters 31 that cover the outer peripheral surface of the roller unit 24 are arranged side by side, and the heating rates are controlled by different power supply control units 32, respectively. Accordingly, by appropriately controlling the rate of temperature increase of each heater 31 individually, it is possible to suppress the occurrence of a temperature distribution on the outer peripheral surface of the roller unit 24. By suppressing the occurrence of the temperature distribution on the outer peripheral surface, the heat input from the outer peripheral surface can be made uniform, so that the temperature distribution on the inner peripheral surface of the roller unit 24 can be suppressed.

{Circle around (2)} Since the plurality of heaters 31 covering the outer peripheral surface of the roller portion 24 are arranged side by side so as to increase the heat generation density, each heater 31 is downsized. Thus, the temperature distribution in each heater 31 can be reduced, so that the occurrence of a temperature distribution on the outer peripheral surface of the roller unit 24 can be suppressed.

[Modification 1]
Modification 1 of the present embodiment will be described.
The present modified example is different from the above embodiment in that the roller unit 24 is heated in a state where the metal foil is provided between the outer peripheral surface of the roller unit 24 and the heater 31. It is preferable that the metal foil be easily deformable and have good thermal conductivity, and for example, an aluminum foil is suitable. Alternatively, a copper foil or the like may be used.

It has been found that in a state in which the heater 31 is in close contact with the outer peripheral surface of the roller portion 24, the heat flux from the heater 31 to the roller portion 24 changes greatly, and the temperature rising state of the roller inner surface changes.
In the heating step, the heater 31 and the roller portion 24 are fixed by, for example, securing the heater 31 to the outer peripheral surface of the roller portion 24 with a wire or the like at a plurality of locations in the vertical direction of the outer peripheral surface without rattling. (Hereinafter, referred to as “normally fixed state”). The heater 31 is desirably provided so as to be in close contact with the outer peripheral surface of the roller portion 24 as much as possible. However, in actuality, at the start of heating, the state of thermal contact is not always sufficiently high. It is presumed that the heat transfer coefficient to the roller portion 24 may be about ～ to 1/10 as compared with the case where the heater 31 is completely in close contact thermally.

That is, when the heater 31 is in close contact with the outer surface of the roller and the heat transfer coefficient is improved, for example, by a factor of five, the temperature of the inner surface of the roller increases approximately 20% faster, and the temperature difference between the outer surface of the roller and the inner surface of the roller also decreases. 20% reduction.

This can be determined from FIGS. 11 and 12.
FIG. 11 shows the relationship between the elapsed time (minutes) and the heater temperature (° C.) or the roller inner surface temperature (° C.). Further, a solid line 111 in FIG. 11 indicates a heater temperature when the temperature is increased at a rate of 10 ° C./30 minutes, and a broken line 112 indicates a heater temperature when the temperature is increased at a rate of 50 ° C./30 minutes. Reference numeral 113 denotes a roller inner surface temperature when the temperature is raised at a temperature rising rate of 10 ° C./30 minutes in the normal fixed state, and a broken line 114 denotes a roller inner surface temperature when the temperature is raised at a temperature rising rate of 50 ° C./30 minutes in the normal fixed state. And a two-dot chain line 115 indicates the roller inner surface temperature when the heater 31 and the roller section 24 are heated at a heating rate of 50 ° C./30 minutes in a contact state in which the thermal contact state is improved.
When the broken line 114 is compared with the two-dot chain line 115, even when the same elapsed time, when the heater 31 and the roller unit 24 are in the close contact state in which the thermal close state is improved, the state is higher than in the normal fixed state. Also, it can be seen that the roller inner surface temperature is high (see the arrow in FIG. 11).

FIG. 12 shows the relationship between the elapsed time (minutes) and the temperature difference ΔT (° C.) between the heater temperature (° C.) or the roller outer surface temperature and the roller inner surface temperature. In addition, a broken line 121 in FIG. 12 indicates a heater temperature when the temperature is raised at a heating rate of 50 ° C./30 minutes, and a broken line 122 indicates a heater temperature when the temperature is raised at a heating rate of 50 ° C./30 minutes in a normal fixed state. The two-dot chain line 123 indicates the temperature difference between the roller outer surface temperature and the roller inner surface temperature, and the temperature is increased at a heating rate of 50 ° C./30 minutes in a contact state where the heater 31 and the roller section 24 are in a close contact state. 4 shows a temperature difference between the roller outer surface temperature and the roller inner surface temperature at the time of the operation.
Comparing the dashed line 122 with the two-dot chain line 123, even when the same elapsed time, when the heater 31 and the roller unit 24 are in a close contact state in which the thermal close state is improved, the state is higher than in the normal fixed state. It can be seen that the temperature difference between the roller outer surface temperature and the roller inner surface temperature is smaller (see the arrow in FIG. 12).

In this modification, the following operation and effect can be obtained.
In this modification, a metal foil is provided between the roller unit 24 and the heater 31. Since the metal foil is easily deformed, the metal foil provided between the roller section 24 and the heater 31 is deformed into a shape corresponding to the gap between the roller section 24 and the heater 31, and And the heater 31. By providing the metal foil between the roller unit 24 and the heater 31, the gap formed between the roller unit 24 and the heater 31 can be filled with the metal foil.

(4) Since the metal foil has good thermal conductivity, filling the gap formed between the roller portion 24 and the heater 31 with the metal foil improves the heat conductivity between the roller portion 24 and the heater 31. Thereby, the heat flux from the heater 31 to the roller unit 24 can be increased. Therefore, the heat of the heater 31 is easily transmitted to the inner peripheral surface of the roller portion 24, and the temperature on the inner peripheral surface is suitably increased. Therefore, the temperature distribution on the inner peripheral surface of the roller unit 24 can be suppressed, and the occurrence of uneven stress in the entire roller unit 24 can be suppressed. Therefore, the roller portion 24 can be hardly damaged.

[Modification 2]
Next, a second modification of the present embodiment will be described.
In this modification, the measurement data collected in the heating step and the fitting step of the roller unit 24 are stored in a database in accordance with the conditions of the plurality of predetermined heater heating rates and the structure of the plurality of roller units 24, A table of data has been built. A table based on a database is created by previously accumulating data on the structure of the roller unit 24 with respect to the heater heating speed, the temperature of each part of the roller unit 24 due to heating, and the measured value of the thermal expansion amount of the roller inner diameter. That is, the control device (not shown) stores the heating rate of the heater 31 and the thermal expansion amount of the roller unit 24 in the heating step (heating rate storage step, thermal expansion amount storing step), and stores the stored heating rate. And a table that defines the relationship between the temperature rise rate and the amount of thermal elongation based on the thermal elongation and the table (table creating step), and stores the table.
Here, a preliminary heating test is performed in which the roller unit 24 is heated at a temporary heating rate at a site where the crusher 1 is located. This makes it possible to select an appropriate temperature increase rate for the heat treatment of the roller and perform heating within a range of appropriate heating conditions for the roller unit 24.
In the preheating test, for example, the roller unit 24 is preheated for about 10 minutes at a predetermined heating rate, and the amount of thermal elongation and the heating rate over time (for example, one to two conditions) are performed. This is a test in which correlation data is collected and compared with an accumulated database (table) to judge and select an appropriate heating rate. Further, in the heating step, preliminary heating is performed on the roller unit 24 at a temporary heating rate, and the roller unit 24 is determined based on the table and the thermal expansion amount of the roller unit 24 at the temporary heating rate and the preliminary heating. The heating of the roller unit 24 may be performed at the increased temperature rising rate.

Further, the selected heating rate can be set under such a condition that the temperature difference due to a sharp temperature gradient between the inner surface of the roller and the outer surface of the roller does not become large, so that the generation of stress to the hardened portion 26 provided on the outer peripheral surface of the roller is reduced. This is preferable because it can suppress partial damage.

According to this modification, the following operation and effect can be obtained.
In the present modified example, an appropriate heating rate of the heat treatment of the roller unit 24 is previously selected by a preliminary heating test, and heating is performed within a range of appropriate heating conditions of the roller unit 24. Thus, it is possible to suppress the occurrence of stress on the hardened portion 26 provided on the substrate, to suppress partial damage, and to shorten the working time in the heating step.

In the present modified example, an example in which the heating condition is determined by a table based on the database has been described. However, by accumulating the data of the heating condition, the AI range is determined so that the appropriate range of the heating condition for the size of each roller can be determined. A system may be constructed, and an appropriate heating rate such as a heating rate or a target heating temperature may be determined by the AI system.

[Modification 3]
Next, a third modification of the present embodiment will be described.
This modification is different from the above embodiment in that the heating rate is changed within a proper range of 1 ° C./min to 2 ° C./min in the heating step.
In the present modified example, as shown in FIG. 13, the heater 31 is heated at a heating rate of 1 ° C./min (first heating rate) only for a predetermined time (ten and several minutes in this embodiment) from the start of heating. Thus, the outer peripheral surface of the roller portion 24 is heated (first heating step), and after a predetermined time has elapsed, the heater 31 is heated at a heating rate of 2 ° C./min (second heating rate). To heat the outer peripheral surface of the roller portion 24 (second heating step).

The change in the temperature difference between the inner surface of the roller and the outer surface of the roller when the heating rate is changed will be described with reference to FIG. FIG. 13 is a graph showing changes in the temperature of the heater 31, the temperature of the inner surface of the roller, and the temperature difference ΔT between the inner surface of the roller and the outer surface of the roller with the elapsed time, in which the horizontal axis indicates the elapsed time (minutes) and the vertical axis indicates the elapsed time. Indicates a temperature difference (ΔT) or a temperature (° C.). The shaded portion indicates the elapsed time zone when the required thermal elongation reaches 0.2 mm.

{Circle around (1)} The broken line 131 in FIG. 13 indicates the heater temperature when the temperature is increased at a rate of 50 ° C./30 minutes. Further, a solid line 132 indicates the heater temperature when the heating rate is changed. A broken line 133 indicates the roller inner surface temperature when the temperature is increased at a rate of 50 ° C./30 minutes. Further, a solid line 134 indicates the roller inner surface temperature when the heating rate is changed. A broken line 135 indicates a temperature difference between the inner surface of the roller and the outer surface of the roller when the temperature is increased at a temperature increase rate of 50 ° C./30 minutes. A solid line 136 indicates a temperature difference between the inner surface of the roller and the outer surface of the roller when the heating rate is changed.

By comparing the dashed line 133 with the solid line 134, there is almost no difference between the roller inner surface temperature when the temperature is increased at a heating rate of 50 ° C./30 minutes and the roller inner surface temperature when the heating rate is changed. I understand that there is no. Further, by comparing the broken line 135 with the solid line 136, the case where the heating rate is changed at a predetermined time from the start of heating is more effective than the case where the heating is performed at a heating rate of 50 ° C./30 minutes. Also, it can be seen that the temperature difference between the roller inner surface and the roller outer surface is reduced. Even when the required thermal elongation is reached, the temperature difference between the roller inner surface and the roller outer surface is greater when the heating rate is changed than when the temperature is increased at a heating rate of 50 ° C./30 minutes. Is reduced by about 5 ° C.

As described above, by increasing the temperature of the heater 31 at a temperature increasing rate of 1 ° C./min only for a predetermined time (ten and several minutes in this embodiment) from the start of heating, a sharp temperature gradient is generated on the outer surface of the roller. Thus, it is possible to suppress an increase in the temperature difference between the inner surface of the roller and the outer surface of the roller. Further, thereafter, the outer peripheral surface of the roller portion 24 is heated by raising the temperature of the heater 31 at a temperature rising rate of 2 ° C./min to obtain a necessary thermal elongation (0.2 mm). By reducing the temperature difference from the outer surface, the generation of stress on the hardened portion 26 of the crushing roller 5 can be suppressed. Therefore, the roller portion 24 can be hardly damaged. Further, the inner surface temperature of the roller hardly changes between the case where the heating rate is 50 ° C./30 minutes and the case where the heating rate is changed. However, the operation time related to the heating step does not increase.

According to this modification, the following operation and effect can be obtained.
An increase in the temperature difference between the outer peripheral surface and the inner peripheral surface of the roller portion 24, which is caused by a rapid temperature rise on the outer peripheral surface of the roller portion 24 with the start of heating, is suppressed. Can be reduced. Therefore, the roller portion 24 can be hardly damaged.

Note that the predetermined time for changing the heating rate is not limited to the above description. The predetermined time is a temperature at which the required thermal elongation (0.2 mm) can be obtained by determining the temperature of the roller outer peripheral surface by the higher one of the heating rate before the change and the heating rate after the change. (Eg, about 30 ° C. to 50 ° C.) or more, about よい to の of the time required for heating.
In addition, a predetermined time may be set in advance, and the heating rate may be set in accordance with the predetermined time.

Note that the present invention is not limited to the invention according to the above-described embodiment, and can be appropriately modified without departing from the gist thereof.
For example, each of the modifications may be combined.
Further, for example, in the above-described embodiment, the roller portion 24 having the outer diameter L1 of about 1.5 m and the inner diameter L4 of about 1.1 m has been described, but the present invention is not limited to this. The roller portion 24 having an inner diameter of about 0.5 m to about 1.8 m can be suitably heated.

1: crusher 2: housing 2a: side surface 2b: ceiling surface 2c: bottom surface 3: air supply duct 4: crush table 5: crush roller 7: fuel supply pipe 8: rotary separator 9: outlet port 15: rotation support 16: Table 17: Journal shaft 18: Journal head 19: Eccentric shaft 20: Pressing device 21: Stopper 23: Journal housing (support)
Reference numeral 24: roller portion 25: base portion 26: hardening portion 27: insulating brick 29: heat insulating material 30: heating device 31: heater 32: power supply control portion 33: power supply portion 34: temperature measuring device

Claims

Used in a crusher for crushing the object to be crushed, a support portion rotatably supported with respect to a housing of the crusher, an annular base portion and the base portion provided on a radially outer peripheral surface of the base portion. An annular roller portion having a cured portion having a different coefficient of thermal expansion, and a method of manufacturing a pulverizing roller including:
In a state where the central axis of the roller portion is in a direction orthogonal to the floor surface, and in a state where the radial inner peripheral surface of the roller portion is open to the outside air, the radial outer peripheral surface side of the roller portion A heating step of heating the roller portion from
An arranging step of arranging the supporting portion and the roller portion in a state where the temperature is increased by the heating step, such that the inner peripheral surface of the roller portion faces or contacts the outer peripheral surface of the supporting portion;
A method of manufacturing the pulverizing roller, comprising: cooling the roller portion arranged in the disposing step, and fitting the supporting portion and the roller portion.
The method according to claim 1, wherein the hardened portion includes at least a part of a member having a smaller coefficient of thermal expansion than the base.
In the heating step, a lower space is formed between the roller portion and the floor surface, and in a state where the lower space communicates with an inner space formed inside the inner peripheral surface of the roller portion, The method according to claim 1, wherein the roller unit is heated.
In the heating step, while covering the radial outer peripheral surface of the roller portion with a heater, and heating the heater in a state where the radial outer peripheral surface of the heater is covered with a heat insulating material, the roller portion is heated. The method for producing a crushing roller according to claim 1, wherein the crushing roller is heated.
The method according to claim 4, wherein, in the heating step, the roller unit is heated while the heater is heated from a room temperature state at a predetermined heating rate.
The method according to claim 5, wherein the predetermined heating rate is 1 ° C / min or more and 2 ° C / min or less.
The method according to any one of claims 4 to 6, wherein, in the heating step, a metal foil is provided between the roller unit and the heater.
The heating step includes a first heating step of heating the roller unit by heating the heater at a first heating rate until a predetermined time has elapsed from the start of heating, and after the first heating step. 8. A second heating step of heating the roller section by heating the heater at a second heating rate higher than the first heating rate. 3. The method for producing a crushing roller according to 1.
The heater is provided in plurality,
The plurality of heaters are arranged side by side in the circumferential direction so as to be along the outer peripheral surface of the roller portion, and the heating rates are controlled by different heating rate control units, respectively. A method for manufacturing the grinding roller according to claim 8.
A heating rate storing step of storing a heating rate of the heater in the heating step;
A thermal expansion amount storage step of storing a thermal expansion amount of the roller unit in the heating step,
Table creation for creating a table that defines the relationship between the heating rate and the thermal elongation based on the heating rate stored in the heating rate storing step and the thermal elongation stored in the thermal elongation storing step. And a process,
In the heating step, the preliminary heating is performed on the roller unit at a provisional heating rate, and based on the provisional heating rate and the amount of thermal expansion of the roller unit in the preliminary heating, and the table. The method for manufacturing a crushing roller according to any one of claims 5 to 9, wherein the heating of the roller unit is performed at the determined heating rate.
An annular roller portion used for a crusher for crushing an object to be crushed, having an annular base portion and a hardening portion provided on a radially outer peripheral surface of the base portion and having a different coefficient of thermal expansion than the base portion. A temperature raising device for raising the temperature of
A heater provided to cover a radially outer peripheral surface of the roller unit;
A heating rate control unit that controls a heating rate of the heater,
The temperature increasing device controls the heater so that the temperature increasing speed is 1 ° C./min or more and 2 ° C./min or less.
The heater is provided for the roller portion arranged such that a central axis is in a direction orthogonal to the floor surface, and a radially inner peripheral surface of the roller portion is open to the outside air. The heating device according to claim 11, wherein:
The heater is provided in plurality,
The plurality of heating rate control units are provided,
The plurality of heaters are arranged side by side in the circumferential direction so as to be along the outer circumferential surface of the roller portion in the radial direction, and the heating rates are controlled by different heating rate controllers, respectively. The temperature raising device according to claim 11 or 12.