JP2014180650A - Coal mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to attenuate excess oscillations generating when pulverizing coals in a coal mill whose roller is supported by a spring type support mechanism.SOLUTION: A spring type support mechanism 32 supporting a roller is configured by a stud 42 by which the reactive force affecting the roller is transmitted to an axial direction through an arm 34, and a coil spring 50 disposed between a diametrally enlarged part 44 integrated with the stud 42 and the end plate 48 of a hollow cylindrical body 46. The attenuation mechanism formed at the end face of the stud 42 is inserted in a recess 52 with a planar inner face having an equally-spaced size in an axial direction and is configured by a friction plate 54 slidably contacting with the inner face of the recess 52.

Description

  The present invention relates to a coal mill that supports, with a spring-type support mechanism, a roller that receives a reaction force from coal during coal pulverization.

In order to supply pulverized coal to a coal-fired boiler, a coal mill for pulverizing coal is used. The coal mill has a crushing table that is attached to a shaft shaft and rotates, and a plurality of rollers that bite into the coal that has fallen on the crushing table and that also roll itself with the frictional force of the coal and the crushing table to crush the coal. It has.
Since the roller receives a reaction force from the coal during coal pulverization, the roller needs to be elastically supported by the mill body. At present, a spring-type support mechanism and a hydraulic-type support mechanism are employed as roller support mechanisms.

  FIG. 7A schematically shows a spring-type support mechanism, and FIG. 7B schematically shows a hydraulic support mechanism. In FIG. 7A, a roller 102 is placed on the upper surface of the crushing table 100. The rotating shaft 104 of the roller 102 is rotatably supported by a fulcrum 106. The roller 102 is crushed by crushing the coal c dropped on the upper surface of the crushing table 100 by its own weight while rolling by itself with friction with the upper surface of the crushing table 100 generated by its own weight. The rotating shaft 104 is connected to a spring-type support mechanism 110 fixed to a partition wall 112 of the housing via an arm 108. In FIG. 7B, the arm 108 is connected to a piston rod 114a of a hydraulic support mechanism 114 fixed to a partition wall 112 of the housing.

The hydraulic support mechanism has a better damping function than the spring support mechanism, but has a problem of high cost. On the other hand, the spring-type support mechanism is less expensive than the hydraulic support mechanism, but has a dampening function inferior to that of the hydraulic support mechanism. Therefore, during coal pulverization, there is a problem that excessive vibration that occurs when the roller passes through a convex portion formed of coal is not reduced, and the vibration load increases.
In FIG. 8, the excessive vibration curve produced when a roller passes the convex part formed with coal is shown. In the figure, curve A is excessive vibration generated by the spring-type support mechanism, and curve B is excessive vibration generated by the hydraulic-type support mechanism.

  Patent Document 1 discloses a coal mill having a spring-type support mechanism. This spring-type support mechanism elastically receives a reaction force received by a roller from coal by a round bar-shaped pressurizing stud via a coil spring. Moreover, it has the nut screwed together by the outer peripheral surface of the pressurization stud, and the end of a coil spring is contact | abutted to this nut. By rotating the pressurizing stud and moving the nut in the axial direction of the pressurizing stud, the elastic force of the coil spring added to the pressurizing stud can be adjusted.

Special table 2011-524251 gazette

  The spring-type support mechanism disclosed in Patent Document 1 is not provided with a damping mechanism. As described above, the spring-type support mechanism is less expensive than the hydraulic support mechanism, but on the other hand, the damping function is inferior to that of the hydraulic support mechanism. Therefore, there is a problem that excessive vibration generated during coal pulverization is not reduced and vibration load is increased. In addition, since the vibration load is not reduced, the durability and reliability of the coal mill may be impaired.

  An object of the present invention is to make it possible to dampen excessive vibrations that occur during coal pulverization in a coal mill that supports a roller with a spring-type support mechanism in view of the problems of the prior art.

  In order to achieve the above object, the coal pulverization mill of the present invention includes a spring-type support mechanism that elastically supports the roller via a spring member against a reaction force applied to the roller from coal, and a spring-type support mechanism. And a damping mechanism for damping the generated vibration load. Thus, by providing the damping mechanism, the generated vibration load can be reduced. Therefore, it is possible to realize a support mechanism that has a damping function equivalent to that of the hydraulic support mechanism and that is less expensive than the hydraulic support mechanism.

  As one aspect of the present invention, the spring-type support mechanism is composed of a rod-shaped stud to which the reaction force applied to the roller is transmitted in the axial direction, and a spring member that elastically supports the stud, and the damping mechanism includes: It can be constituted by a friction member that is in sliding contact with the stud and attenuates the movement of the stud by frictional resistance. Thereby, both the spring-type support mechanism and the damping mechanism can be simplified and reduced in cost.

Furthermore, as one aspect of the spring member, a coil spring is disposed so as to surround the outer peripheral surface of the stud, and one end abuts on the enlarged diameter portion formed integrally with the outer peripheral surface of the stud and the other end contacts the fixing member. Can be configured. Further, the friction member for this is constituted by a friction plate whose end is inserted into a recess formed in the axial direction on the end surface of the piston rod, is in sliding contact with the inner surface of the recess, and the other end is fixed to the fixing member. be able to. Thereby, the cost of the spring-type support mechanism and the damping mechanism can be further reduced.
The frictional force (friction resistance) acting between the recess and the friction plate is determined by the sliding area formed between them, the clearance, or the surface roughness or hardness of the recess or the friction plate. Therefore, the attenuation function of the attenuation mechanism can be adjusted by adjusting these factors.

  As one aspect of the present invention, the spring-type support mechanism is composed of a stud to which the reaction force applied to the roller is transmitted in the axial direction, and a spring member that elastically supports the stud, and the damping mechanism is fixed to the housing. The cylinder in which the compressible liquid is sealed, the piston rod penetrating the inside of the cylinder, and the piston rod are integrally formed to bisect the internal space of the cylinder, and the compressible liquid flows. And a piston having a through hole. Then, the stud and the piston rod are coupled in the same axial direction.

  The damping mechanism having the above-described configuration has a configuration equivalent to that conventionally referred to as a shock absorber or a cylinder damper. By using the attenuation mechanism having such a configuration, an excellent attenuation effect can be obtained.

  Further, the spring member can be constituted by a coil spring having one end abutting on the enlarged diameter portion formed on the outer peripheral surface of the stud and the other end abutting on the end surface of the cylinder. As a result, the spring-type support mechanism can be simplified and reduced in cost.

According to still another aspect of the present invention, a spring-type support mechanism including the piston rod and the coil spring is used as a spring-type support mechanism. And the damping mechanism of the said structure called a shock absorber or a cylinder damper is used as a damping mechanism. A friction plate that is inserted into a recess formed in the axial direction on the end surface of the piston rod and is in sliding contact with the inner surface of the recess is coupled to the piston rod in the same axial direction. In this aspect, the other end of the coil spring is in contact with and supported by the end face of the cylinder.
As a result, a great damping effect can be obtained by a synergistic effect of the damping effect produced by the frictional resistance between the recess and the friction plate and the damping effect produced by the shock absorber or cylinder / damper type damping mechanism.

  Furthermore, the friction plate can be configured such that the relative position with respect to the recess can be adjusted in the advancing and retracting direction with respect to the recess. This facilitates adjustment of the attenuation function.

  According to the present invention, by providing a damping mechanism in the spring-type support mechanism that supports the roller, the vibration load generated in the spring-type support mechanism can be reduced, and the reliability and durability of the coal mill are improved at low cost. it can.

1 is an overall configuration diagram of a coal mill according to a first embodiment of the present invention. It is a longitudinal cross-sectional view of the roller support mechanism of the coal mill. It is a partially expanded sectional view of the roller support mechanism. It is a diagram which shows the damping effect of the said roller support mechanism. It is a longitudinal cross-sectional view of the roller support mechanism which concerns on 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the roller support mechanism which concerns on 3rd Embodiment of this invention. (A) is a schematic diagram of a spring-type support mechanism, and (B) is a schematic diagram of a hydraulic support mechanism. It is a diagram which shows the excessive vibration curve produced with the conventional spring type | formula support mechanism and the hydraulic type support mechanism.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to that unless otherwise specified.

(Embodiment 1)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an overall view of a coal mill according to the present embodiment. In FIG. 1, a vertical coal mill 10 includes a substantially cylindrical housing 12. Power is transmitted from the mill driving motor 14 to the speed reducer 18 through the coupling 16. With this power, the crushing table 20 rotates around the vertical axis. Three rollers 22 are arranged at equal intervals in the circumferential direction on the crushing table. A frictional force is generated between the roller 22 and the upper surface of the crushing table 20 due to its own weight, and the roller 22 is rotated around the crushing table 20 by the frictional force. That is, it rotates around the rotation shaft 22a.

  Coal c is supplied through the supply pipe 24 from above the center of the crushing table 20. The coal c dropped on the upper surface of the crushing table 20 is crushed and crushed by the rolling roller 22. The pulverized coal is moved to the periphery of the table by the centrifugal force generated by the rotation of the pulverizing table 20. The pulverized coal is introduced from a hot air supply pipe 26 provided at the lower portion of the pulverizing table 20, and is dried and blown up by the hot air ejected from the gap between the housing 12 and the outer peripheral portion of the pulverizing table.

  The blown-up pulverized coal is classified into fine powder and coarse powder by a classifier 28 provided above the crushing table 20. The classified fine powder is discharged from the vertical coal mill 10 through the discharge pipe 30, and the coarse powder falls onto the pulverizing table 20 and is pulverized again with the coal c. Reaction force of coal c is applied to the roller 22. Therefore, a spring-type support mechanism 32 that elastically supports the roller 22 is provided. Hereinafter, the configuration of the spring-type support mechanism 32A will be described with reference to FIG.

  In FIG. 2, an arm 34 is attached to the rotating shaft 22 a of the roller 22 in a substantially perpendicular direction. The rotating shaft 22a and the arm 34 are rotatable around the arm shaft 35 in the direction of the arrow, respectively. An opening is formed in the housing 12, and a hollow cylindrical base 36 is inserted and fixed in the opening. A sleeve 38 having a flange 38a is inserted and fixed to the pedestal 36 from the outside, and a sleeve 40 having a support portion 40a having a reduced diameter at the inner end is inserted and fixed to the pedestal 36 from the inside. Inside these sleeves, round bar-like studs 42 are inserted so as to be slidable in the axial direction. The arm 34 is formed with a spherical engaging seat 34a, and one end of the stud 42 is in contact with the engaging seat 34a.

  One end side portion of the stud 42 is a small diameter portion 42a, and an enlarged diameter portion 44 is formed integrally with the small diameter portion 42a. A flange 46 a of the hollow cylindrical body 46 is bolted to the flange 38 a of the sleeve 38. A circular end plate 48 is bolted to the other flange 46 b of the hollow cylindrical body 46. A coil spring 50 is inserted into the internal space of the hollow cylindrical body 46 formed by the enlarged diameter portion 44 and the end plate 48. The coil spring 50 is disposed around the stud 42. On the outer end surface of the stud 42, a concave portion 52 having a planar inner surface having an equally spaced dimension in the axial direction is formed. One end of the friction plate 54 is inserted into the recess 52 and is in sliding contact with the inner surface of the recess 52.

  A male screw part 54 a is formed at the other end of the friction plate 54. The male screw portion 54a protrudes from the hole 48a formed at the center of the end plate 48 to the outside of the hollow cylindrical body 46, and a nut 56 is screwed into the male screw portion 54a. By rotating the nut 56, the friction plate 54 can be moved in the axial direction, and the amount of the friction plate 54 inserted into the recess 52 can be adjusted. A cushion 57 is interposed between the coil spring 50 and the end plate 48. An adjustment bolt 58 is screwed into the pedestal 36, the flange 38 a of the sleeve 38, and the flange 46 a of the hollow cylindrical body 46, and the insertion amount of the sleeve 38 with respect to the pedestal 36 can be adjusted with the adjustment bolt 58.

  In this configuration, the reaction force that the roller 22 receives from the coal c is transmitted to the coil spring 50 through the rotation of the arm 34 and the movement of the stud 42 in the axial direction. The roller 22 is elastically supported by the coil spring 50. Further, due to the movement of the stud 42 in the axial direction, the inner surface of the recess 52 and the friction plate 54 come into sliding contact. The frictional resistance generated between the inner surface of the recess 52 and the friction plate 54 can reduce excessive vibration that occurs when the roller 22 passes through the protrusion formed of coal c.

  FIG. 3 is an enlarged view of the recess 52 and the friction plate 54. The frictional resistance generated between the inner surface of the recess 52 and the friction plate 54 is the sliding area between the recess 52 and the friction plate 54 and between the inner surface of the recess 52 and the friction plate 54. The clearance t, the roughness of the sliding surface between the recess 52 and the friction plate 54, the hardness of the friction plate 54, and the like. For example, by increasing the hardness of the friction plate 54, the frictional resistance between the two can be increased and the damping effect can be increased.

  FIG. 4 is a diagram showing the relationship between the various factors and the attenuation effect. In FIG. 4, as the clearance t becomes smaller, the damping effect becomes larger, but there is a threshold value S at which the friction plate 54 cannot slide. The damping effect varies depending on the surface roughness, sliding area, hardness, and the like of the recess 52 and the friction plate 54. Accordingly, the value of the clearance t at which the friction plate 54 cannot slide varies depending on the surface roughness, sliding area, hardness, and the like.

  According to the present embodiment, since the spring-type support mechanism 32A having a damping function constituted by the friction plate 54 and the like is provided, even if excessive vibration occurs in the roller 22, low-cost support that can reduce the vibration load. The mechanism can be realized. Therefore, the reliability and durability of the vertical coal mill 10 can be improved. Further, the spring type support mechanism 32A is constituted by the piston rod 42 and the coil spring 50, and the damping mechanism is also the main member of the friction plate 54, so both can be reduced in cost. Further, by adjusting the clearance t between the recess 52 and the friction plate 54, the area of the sliding surface between the recess 52 and the friction plate 54, the surface roughness, the hardness of the friction plate 54, and the like, the damping function can be easily adjusted. Become. Further, by adjusting the nut 56, the sliding area between the recess 52 and the friction plate 54 can be adjusted, and this also facilitates the adjustment of the damping function.

(Embodiment 2)
Next, a second embodiment of the present invention will be described with reference to FIG. In the spring type support mechanism 32B of the present embodiment, a shock absorber 60 is provided at the end of the small diameter portion 42a of the stud 42. In the present embodiment, the hollow cylindrical body 46 has a dimension that is longer in the axial direction than the first embodiment, and the shock absorber 60 is disposed inside the hollow cylindrical body 46.

  The shock absorber 60 includes a cylinder 62 filled with compressible oil o inside, a piston rod 64 disposed through holes formed in the center of both end surfaces of the cylinder 62, and the piston rod 64. The piston 66 is formed together with a piston rod 64 and a piston 66 slidably disposed inside the cylinder 62. The piston 66 is formed with a small-diameter through hole 66a through which the oil o flows. The piston rod 64 is tightly fitted and fixed in a hole formed in the axial direction on the end face of the stud 42, and is disposed on the same axis as the stud 42.

  Both ends of the coil spring 50 are in contact with the enlarged diameter portion 44 and the end face of the cylinder 62. The end of the hollow cylindrical body 46 is closed with an end plate 48, and a male screw portion 54 a is formed at the end of the piston rod 64. The male screw portion 54a protrudes from the hole 48a formed at the center of the end plate 48 to the outside of the hollow cylindrical body 46, and a nut 56 is screwed into the male screw portion 54a. By turning the nut 56, the diameter-expanded portion 44 can be moved in the axial direction, and the elastic force of the coil spring 50 added to the stud 42 can be adjusted.

  A cushion 68 is interposed between the coil spring 50 and the end surface of the cylinder 62, and a cushion 70 is interposed between the other end surface of the cylinder 62 and the end plate 48. Other configurations are the same as those of the first embodiment, and the same members or the same devices are denoted by the same reference numerals as those of the first embodiment.

  The damping mechanism of the present embodiment is configured with a shock absorber 60. The reaction force of the coal c applied to the roller 22 is transmitted to the piston rod 64 via the stud 42. The vibration load applied to the piston rod 64 is reduced by the flow resistance of the oil o flowing through the through hole 66a.

  According to the present embodiment, in addition to the operational effects obtained in the first embodiment, the damping effect can be further improved by providing the shock absorber 60. Moreover, since the position of the enlarged diameter part 44 of the stud 42 can be moved by adjusting the nut 56, the elastic force of the coil spring 50 applied to the stud 42 can be easily adjusted.

(Embodiment 3)
Next, a third embodiment of the present invention will be described with reference to FIG. In the spring-type support mechanism 32 </ b> C of this embodiment, the end portion of the piston rod 64 on the stud 42 side is constituted by a friction plate 72. The engagement state between the friction plate 72 and the stud 42 is the same as that in the first embodiment. That is, the end surface of the stud 42 is provided with a concave portion 52 having a planar inner surface having an equally spaced dimension in the axial direction, and one end of the friction plate 72 is inserted into the concave portion 52. The friction plate 54 is in sliding contact with the inner surface of the recess 52. Therefore, a frictional resistance is generated between the recess 52 and the friction plate 72, and a damping force is generated by this frictional resistance. Other configurations are the same as those of the second embodiment.

According to this embodiment, in addition to the operational effects obtained in the second embodiment, the damping effect is a synergistic effect of the damping effect caused by the frictional resistance generated between the recess 52 and the friction plate 72 and the damping effect caused by the shock absorber 60. The effect can be dramatically improved.
Further, as in the first embodiment, the clearance t between the recess 52 and the friction plate 54, the area of the sliding surface between the recess 52 and the friction plate 54, the surface roughness, the hardness of the friction plate 54, and the like are adjusted. This makes it easy to adjust the damping function. Further, by adjusting the nut 56, the sliding area between the recess 52 and the friction plate 54 can be adjusted, and this also facilitates the adjustment of the damping function.

  ADVANTAGE OF THE INVENTION According to this invention, the coal mill which can attenuate the excessive vibration produced at the time of coal pulverization as a support mechanism of a roller is realizable.

DESCRIPTION OF SYMBOLS 10 Vertical coal mill 12 Housing 14 Mill drive motor 16 Coupling 18 Reducer 20 Grinding table 22 Roller 22a Rotating shaft 24 Supply pipe 26 Hot air supply pipe 28 Classifier 30 Discharge pipe 32A, 32B, 32C Spring type support mechanism 34 Arm 34a Engagement seat part 35 Arm shaft 36 Base 38, 40 Sleeve 38a Flange 40a Support part 42 Stud 42a Small diameter part 44 Wide diameter part 46 Hollow cylindrical body 46a, 46b Flange 48 End plate 48a Hole 50 Coil spring 52 Concave part 54, 72 Friction Plate 54a Male thread part 56 Nut 57, 68, 70 Cushion 58 Adjustment bolt 60 Shock absorber 62 Cylinder 64 Piston rod 66 Piston 66a Through hole S Threshold c Coal o Oil t Clearance

Claims (7)

A crushing table attached to the shaft and rotating;
In a coal mill equipped with a plurality of rollers that bite into the coal that has fallen on the crushing table and roll itself to crush the coal,
A spring-type support mechanism that elastically supports the roller via a spring member against a reaction force applied to the roller from the coal;
A coal mill comprising: a damping mechanism for damping a vibration load generated in the spring-type support mechanism. The spring-type support mechanism is
A stud to which the reaction force applied to the roller is transmitted in the axial direction;
A spring member that elastically supports the stud,
2. The coal mill according to claim 1, wherein the damping mechanism includes a friction member that is in sliding contact with the stud and attenuates the movement of the stud by a frictional resistance. The spring member is arranged so as to surround the outer peripheral surface of the stud, and is configured by a coil spring in which one end abuts on the enlarged diameter portion formed integrally with the outer peripheral surface of the stud and the other end abuts on the fixing member. ,
The friction member is configured by a friction plate having an end portion inserted into a recess formed in the axial direction on the end surface of the stud, slidingly contacting the inner surface of the recess, and the other end fixed to the fixing member. The coal mill according to claim 2. The spring-type support mechanism is
A stud to which the reaction force applied to the roller is transmitted in the axial direction;
A spring member that elastically supports the stud,
The damping mechanism is
A cylinder fixed to the housing and filled with a compressible liquid;
A piston rod passing through the inside of the cylinder;
The piston rod is formed integrally with the piston rod and bisects the internal space of the cylinder, and includes a piston having a through hole through which the compressible liquid flows.
The coal mill according to claim 1, wherein the stud and the piston rod are coupled in the same axial direction.   The said spring member is comprised by the coil spring by which one end contact | abutted to the enlarged diameter part integrally formed in the outer peripheral surface of the said stud, and the other end contact | abutted to the end surface of the said cylinder. 4. The coal mill according to 4. The fixing member is a cylinder fixed to a housing and filled with a compressible liquid inside.
The friction plate is coupled in the same axial direction as a piston rod penetrating the inside of the cylinder,
4. The coal mill according to claim 3, wherein the piston rod has a piston that is slidably disposed inside the cylinder and has a through-hole through which the compressible liquid flows.   7. The coal mill according to claim 3, wherein the friction plate can be adjusted in a forward / backward direction relative to the concave portion with respect to the concave portion.

Images