AU2018325823B2 - Gyratory crusher - Google Patents

Abstract

Lubricating oil is supplied to a gap between an outer peripheral surface of a lower part of a main shaft (5) inserted into a main shaft insertion hole (3) for a main shaft bearing (10), and a surface that forms the main shaft insertion hole (3), thus forming the main shaft bearing (10). Lubricating oil is supplied to a gap between an outer peripheral surface of an eccentric sleeve (4) inserted into an eccentric sleeve insertion hole (27), and a surface that forms the eccentric sleeve insertion hole (27), thus forming an eccentric sleeve bearing (11). The main shaft bearing (10) and/or the eccentric sleeve bearing (11) has an area that is robust in terms of changes in the minimum oil film thickness of the lubricating oil relative to changes in the power of a motor that rotatably drives the main shaft (5). This gyratory crusher can robustly adapt to a wide variety of objects to be crushed, and can also robustly adapt to changes in load conditions.

Description

Technical Field

[0001] The present invention relates to a gyration-type

crusher such as a gyratory crusher or a cone crusher for

crushing rocks and the like.

Background

[0002] A gyration-type crusher such as a gyratory crusher

or a cone crusher may be used as a crusher for crushing

large raw stones (rocks). Of such gyration-type crushers,

a hydraulic cone crusher will be exemplified in order to

describe its summary and crushing principle, referring to

FIG. 1.

[0003] In the gyration-type crusher illustrated in FIG. 1,

a main shaft 5 whose center axis Li is inclined relative to

a center axis L2 of an upper frame 1 is provided in the

center of the internal space formed of the upper frame 1 in

the shape of a truncated inverted substantial conical

tubular body and a lower frame 2 connected thereto. Note

that, the upper frame 1 and the lower frame 2 are

collectively referred to as a frame 31.

[0004] In the main shaft 5, the lower portion has a

cylindrical outer surface, the lower end portion is

rotatably inserted into a main shaft fitting insertion hole

3 formed in an eccentric sleeve 4 supported by the bottom

portion of the lower frame 2 via an eccentric shaft thrust

bearing 23, and the bottom surface is supported by a thrust

bearing 6. Additionally, the eccentric sleeve 4 is rotatably inserted into an eccentric sleeve fitting insertion hole 27 formed in an outer cylinder 7 whose outer peripheral surface is disposed in the lower frame 2.

Additionally, the upper end portion of the main shaft 5 is

rotatably supported by an upper bearing 17, and the upper

bearing 17 is supported by a spider 18 connected to the

upper frame 1. Note that, the spider 18 forms a beam which

passes through the center of the upper frame 1 and

communicates with the upper end portion of the upper frame

1.

[0005] Here, in the gyration-type crusher illustrated in

FIG. 1, a hydraulic chamber 27 is formed above the

eccentric sleeve 4 and the outer cylinder 7 and on the

inner peripheral side of a cylindrical partition plate 24.

Between the outer peripheral surface of the main shaft 5

inserted into the main shaft fitting insertion hole 3 and

the inner peripheral surface of the eccentric sleeve 4, and

between the outer peripheral surface of the eccentric

sleeve 4 and the inner peripheral surface of the outer

cylinder 7, lubricating oil or the like is supplied from

the hydraulic chamber 27 in order to form an oil film for

ensuring smooth sliding and preventing wear on the sliding

surface to function as a radial sliding bearing. Note

that, in order to prevent dust from entering the hydraulic

chamber 27, a dust seal 25 is attached to the bottom

surface of a mantle core 12 using a dust seal cover 26.

[0006] Hereunder, a bearing portion between the outer peripheral surface of the main shaft 5 inserted into the main shaft fitting insertion hole 3 and the inner peripheral surface of the eccentric sleeve 4 is referred to as a main shaft bearing 10, and a bearing portion between the outer peripheral surface of the eccentric sleeve 4 and the inner peripheral surface of the outer cylinder 7 is referred to as an eccentric sleeve bearing 11. Further, the main shaft bearing 10 and the eccentric sleeve bearing

11 may be referred to as a bearing 15 without being

particularly distinguished (with being abstracted).

[0007] On the outer surface of the upper portion of the

main shaft 5, the mantle core 12 whose outer peripheral

surface forms a truncated substantial conical surface is

firmly mounted by shrink fitting. On the outer surface of

the mantle core 12, a mantle 13 which is manufactured from

wear resistant material (for example, high manganese cast

steel) and whose outer peripheral surface forms a truncated

substantial conical surface is mounted.

[0008] Additionally, on the inner surface of the upper

frame 1, a conecave 14 which is manufactured from wear

resistant material (for example, high manganese cast steel)

is provided. A crushing chamber 16 is formed of a space

which is formed by the conecave 14 and the mantle 13 and

has a substantial wedge shape with a narrower lower portion

in a vertical section.

[0009] A center axis Li of the main shaft 5 and a center

axis L2 of the upper frame 1 intersect at an intersection point 0 in the upper space of the crusher, and the main shaft 5 is inclined relative to the upper frame 1 in a plane surface including the center axis Li of the main shaft 5 and the center axis L2 of the upper frame 1.

Additionally, the eccentric sleeve 4 has a center axis L4

substantially the same as the center axis L2 of the upper

frame 1, and is arranged so as to be rotatable around L4.

[0010] With this configuration, when the eccentric sleeve 4

connected to a driven side bevel gear 21 rotates about the

center axis L2 of the upper frame 1 via a power

transmission mechanism such as a pulley 22, a horizontal

shaft, a bevel gear 19 (driving side bevel gear 20 and

driven side bevel gear 21) and the like by means of an

electric motor (not illustrated) provided outside the frame

31, the main shaft 5 performs an eccentric rotary motion, a

so-called precession motion, in the crushing chamber 16

with the intersection point 0 as a fixed point in space.

Note that the behavior is ideal geometric one, while in a

real device, during operation or the like, the intersection

o may slightly fluctuate due to deformation of a bearing

gap in the upper bearing 17, a frame (casing) and the like,

and the geometric motion behavior of the main shaft 5 may

slightly fluctuate accordingly. Thereby, the distance

between the outer surface of the mantle 13 and the inner

surface of the conecave 14 at an arbitrary position in the

circumferential direction in a horizontal section at an

arbitrary position on the center axis L2 of the upper frame

1 in the crushing chamber 16 varies with the same period as

the main shaft 5. That is, when the eccentric sleeve 4 is

rotated and the main shaft 5 is turned in the crushing

chamber 16, for example, the position of the shortest

distance between the outer surface of the mantle 13 and the

inner surface of the conecave 14 at the vertical lowest end

of the crushing chamber 16 varies as the main shaft 5 is

turned, as illustrated in FIG. 2.

[0011] A rock to be crushed (hereunder, referred to as

"object to be crushed") 9 is charged from above the crusher

and falls into the crushing chamber 16. In the crushing

chamber 16, the interval between the conecave 14 and the

mantle 13 is tapered downward, and also the width of the

interval varies periodically according to the turning of

the main shaft 5. Thereby, the object to be crushed 9

progresses in crushing while repeating fall and compression,

and objects crushed into pieces smaller than the narrowest

interval between the conecave 14 and the mantle 13 at the

lower portion of the concave 14 are collected from below as

a crushed product.

[0012] Due to the crushing principle of the gyration-type

crusher, in the mantle 13, along with the crushing

(crushing force W), a reaction force P1 from the crushing

position toward the inner peripheral side of a frame 31

acts on the main shaft 5, and a reaction force P2 from the

crushing position toward the outer peripheral side of the

frame 31 acts on the frame 31. By the reaction force P1 acting on the main shaft 5 toward the inner peripheral side, the main shaft 5 moves toward the inner peripheral surface of the eccentric sleeve 4 (translational motion). Further, due to the displacement, deformation, or the like of the main shaft 5 and the frame 31 due to the two reaction forces, the parallelism between the center axis Li of the main shaft 5 and the center axis L3 of the main shaft fitting and insertion hole 3 is lost, and the center axis

Li of the main shaft 5 is inclined with respect to the

center axis L3 of the main shaft fitting and insertion hole

3 (rotational motion). Thereby, in the main shaft bearing

10, the minimum oil film may become thin on the upper end

side or the lower end side, that is, a so-called one-side

contact state. When such one-sided contact progresses, the

outer peripheral surface of the main shaft 5 and the inner

peripheral surface of the eccentric sleeve 4 shift from a

fluid lubrication state through a fluid film to a mixed

lubrication state with microscopic contact or a state in

which solid surfaces slide while contacting each other,

whereby the main shaft 5 and the eccentric sleeve 4 may

reach so-called seizure.

[0013] Similarly, in the eccentric sleeve bearing 11, due

to the reaction force P1 acting on the eccentric sleeve 4

via the main shaft 5, the eccentric sleeve 4 moves toward

the inner peripheral surface of the outer cylinder 7

opposite to the side on which the reaction force P1 acts.

Furthermore, due to the displacement, deformation, or the like of the eccentric sleeve 4 and the frame 31 or the like due to the reaction force P1 on the inner peripheral side acting on the main shaft 5 or the like and the reaction force P2 on the outer peripheral side acting on the frame

31 or the like, the parallelism between the center axis L4

of the eccentric sleeve 4 and the center axis L5 of the

eccentric sleeve fitting and insertion hole 27 is lost, and

the center axis L4 of the eccentric sleeve 4 is inclined

with respect to the center axis L5 of the eccentric sleeve

fitting and insertion hole 27. Thereby, the minimum oil

film may become thin on the upper end side or the lower end

side, that is, a so-called one-side contact state. When

such one-side contact progresses, the outer peripheral

surface of the eccentric sleeve 4 and the inner peripheral

surface of the outer cylinder 7 shift from a fluid

lubrication state through a fluid film to a mixed

lubrication state with microscopic contact or a state in

which solid surfaces slide while contacting each other,

whereby the main shaft 5 and the eccentric sleeve 4 may

reach so-called seizure.

[0014] Hereunder, the one-side contact at the upper end

side of the bearing 15 (main shaft bearing 10 or eccentric

sleeve bearing 11) is referred to as "upper contact", and

the one-side contact at the lower end side is referred to

as "lower contact". Note that, the bearing 15 may have

both the upper contact and the lower contact due to

fluctuations in the state such as the magnitude of the reaction force during the crushing operation, the oil film thickness of the bearing 15 (size of bearing clearance), the deformation of the main shaft 5 and the eccentric sleeve 4.

[0015] Thus, the gyration-type crusher has a feature that

the bearing is essentially susceptible to the one-side

contact due to the crushing principle.

[0016] Further, when the bearing 15 contacts at one side in

this way, a large surface pressure is locally generated at

the end of the bearing 15, and early replacement may be

necessary due to wear, seizure, or the like under load

conditions which are not problems in normal use.

[0017] Further, a rock, which is the main object to be

crushed by a gyration-type crusher, have a wide variety of

strengths and brittleness, and when crushing a kind of

object to be crushed 9 which is difficult to crush, the

reaction force received by the mantle 13 is very large, and

the bearing 15 is worn or damaged in a short time.

Therefore, it was necessary to check the bearing 15 and the

like by adjustment and testing, and to select or use an

appropriate rotatory crusher according to the kind of

object to be crushed 9, which was very troublesome and the

cost and labor has were heavy burdens.

[0018] Moreover, in the gyration-type crusher, the surfaces

of the mantle 13 and conecave 14 gradually wear and the

thickness decreases as the operation progresses, and the

distance between the outer surface of the mantle 13 and the inner surface of the conecave 14 changes (becomes wider).

Therefore, it is necessary to change (adjust) the position

of the upper frame 1 or the position of the main shaft 5

according to the change. Therefore, even if it is the same

kind of object to be crushed 9, a crushing load or its

reaction force changes, and the load condition and the like

with respect to the bearing 15 change.

[0019] Regarding the gyration-type crusher having such

properties, in order to prevent bearing cracking due to one

side contact in the thrust sliding bearing which supports

the main shaft, the proposal of the structure which adopts

a sliding member is made in Patent Document 1. However, no

disclosure or proposal is made about the radial bearing

including the journal bearing (radial sliding bearings).

[0020] Further, in the journal bearing, in order to prevent

damage to the bearing such as wear and seizure due to local

surface pressure acting on the end portion due to one side

contact, the crowning process (providing a crowning

portion) at the end portion may be used. However, there

was a problem that it requires excessive cost, labor, and

time for processing and the like.

[0020a] It is desired to address or ameliorate one or more

disadvantages or limitations associated with the prior art,

or to at least provide a useful alternative.

Related Art Document

Patent Document

[0021] Patent Document 1: Japanese Patent Application

Laid-open No. 2011-11187 A

Summary

[0022] The present invention, at least in some embodiments,

may provide a gyration-type crusher which can cope with a

wide variety of objects to be crushed robustly and can also

cope with the change of load condition robustly.

[0023] A gyration-type crusher according to a first aspect

of the present invention comprises: a main shaft which is

rotatably arranged inside a conecave and which makes an

eccentric rotary movement with its center axis inclined

with respect to a center axis of the conecave; a mantle

provided on the main shaft; an eccentric sleeve having a

main shaft fitting insertion hole into which a lower end

portion of the main shaft is rotatably inserted; an outer

cylinder having an eccentric sleeve fitting insertion hole

into which the eccentric sleeve is rotatably inserted,

wherein an outer peripheral surface of the lower end

portion of the main shaft which is inserted into the main

shaft fitting insertion hole and a surface which forms the

main shaft fitting insertion hole form a main shaft bearing

with a lubricating oil supplied between them,

wherein an outer peripheral surface of the eccentric

sleeve which is inserted into the outer cylinder and a

surface which forms the eccentric sleeve fitting insertion

hole form an eccentric sleeve bearing with a lubricating oil supplied between them, and wherein at least one of the main shaft bearing and the eccentric sleeve bearing has a robust region in a change of a minimum oil film thickness of the lubricating oil with respect to a change of a motor power which rotationally drives the main shaft.

[0024] A second aspect of the present invention is that, in

the first aspect, a rated value of the motor power exists

at or below an upper limit value of the robust region.

[0025] A third aspect of the present invention is that, in

the first or second aspect, a state where a center axis of

at least one of the main shaft bearing and the eccentric

sleeve bearing is substantially parallel to a center axis

of a lower portion of the main shaft exists at or below

the upper limit value of the robust region.

[0026] A fourth aspect of the present invention is that, in

any one of the first to third aspects, the center axis of

at least one of the main shaft bearing and the eccentric

sleeve bearing is substantially parallel to the center axis

of the lower portion of the main shaft at the rated value

of the motor power.

[0027] A fifth aspect of the present invention is that, in

any one of the first to fourth aspects, in at least one of

the main shaft bearing and the eccentric sleeve bearing,

when the motor power which rotationally drives the main

shaft changes from about 50% to about 160% of the rated

value, the position where the oil film thickness of the lubricating oil is minimum changes from a bearing lower end side toward a bearing upper end side.

[0028] A sixth aspect of the present invention is that, in

the fifth aspect, in at least one of the main shaft bearing

and the eccentric sleeve bearing, when the motor power

which rotationally drives the main shaft changes from about

50% to about 160% of the rated value, the position where

the oil film thickness of the lubricating oil is minimum

changes from the bearing lower end side to entire bearing

vertical direction.

[0029] A seventh aspect of the present invention is that,

in any one of the first to fourth aspects, in at least one

of the main shaft bearing and the eccentric sleeve bearing,

when the motor power which rotationally drives the main

shaft changes from about 50% to a maximum allowable value

of the rated value, the position where the oil film

thickness of the lubricating oil is minimum changes from

the bearing lower end side to the entire bearing vertical

direction.

[0030] An eighth aspect of the present invention is that,

in any one of the first to fourth aspects, in at least one

of the main shaft bearing and the eccentric sleeve bearing,

when the motor power which rotationally drives the main

shaft changes from about 50% to a maximum allowable value

of the rated value, a distribution of an oil film pressure

of the lubricating oil changes from a distribution biased

toward a bearing lower portion to a smooth distribution over the entire bearing vertical direction.

[0031] A ninth aspect of the present invention is that, in

any one of the first to fourth aspects, in at least one of

the main shaft bearing and the eccentric sleeve bearing,

when the motor power which rotationally drives the main

shaft changes from about 50% to about 160% of the rated

value, a distribution of the oil film pressure of the

lubricating oil changes from a distribution biased toward a

bearing lower portion to a smooth distribution over the

entire bearing vertical direction.

[0032] A gyration-type crusher according to a tenth aspect

of the present invention comprises: a main shaft which is

rotatably arranged inside a conecave and which makes an

eccentric rotary movement with its center axis inclined

with respect to a center axis of the conecave; a mantle

provided on the main shaft; an eccentric sleeve having a

main shaft fitting insertion hole into which a lower end

portion of the main shaft is rotatably inserted; and an

outer cylinder having an eccentric sleeve fitting insertion

hole into which the eccentric sleeve is rotatably inserted,

wherein an outer peripheral surface of the lower end

portion of the main shaft which is inserted into the main

shaft fitting insertion hole and a surface which forms the

main shaft fitting insertion hole form a main shaft bearing

with a lubricating oil supplied between them, wherein an

outer peripheral surface of the eccentric sleeve which is

inserted into the outer cylinder and a surface which forms the eccentric sleeve fitting insertion hole form an eccentric sleeve bearing with a lubricating oil supplied between them, and wherein in at least one of the main shaft bearing and the eccentric sleeve bearing, when the motor power which rotationally drives the main shaft changes from about 50% to about 160% of the rated value, the position where the oil film thickness of the lubricating oil is minimum changes from a bearing lower portion toward a bearing upper portion.

[0033] A gyration-type crusher according to an eleventh

aspect of the present invention comprises: a main shaft

which is rotatably arranged inside a conecave and which

makes an eccentric rotary movement with its center axis

inclined with respect to a center axis of the conecave; a

mantle provided on the main shaft; an eccentric sleeve

having a main shaft fitting insertion hole into which a

lower end portion of the main shaft is rotatably inserted;

and an outer cylinder having an eccentric sleeve fitting

insertion hole into which the eccentric sleeve is rotatably

inserted, wherein an outer peripheral surface of a lower

portion of the main shaft which is inserted into the main

shaft fitting insertion hole and a surface which forms the

main shaft fitting insertion hole form a main shaft bearing

with a lubricating oil supplied between them, wherein an

outer peripheral surface of the eccentric sleeve which is

inserted into the outer cylinder and a surface which forms

the eccentric sleeve fitting insertion hole form an eccentric sleeve bearing with a lubricating oil supplied between them, and wherein in at least one of the main shaft bearing and the eccentric sleeve bearing, when the motor power which rotationally drives the main shaft changes from about 50% to about 160% of the rated value, the position where the oil film thickness of the lubricating oil is minimum changes from the bearing lower portion to the entire bearing vertical direction.

[0034] A gyration-type crusher according to a twelfth

aspect of the present invention comprises: a main shaft

which is rotatably arranged inside a conecave and which

makes an eccentric rotary movement with its center axis

inclined with respect to a center axis of the conecave;

mantle provided on the main shaft; an eccentric sleeve

provided to a lower end portion of the main shaft; and an

outer cylinder having an eccentric sleeve fitting insertion

hole into which the eccentric sleeve is rotatably inserted,

wherein an outer peripheral surface of the eccentric sleeve

which is inserted into the outer cylinder and a surface

which forms the eccentric sleeve fitting insertion hole

form an eccentric sleeve bearing with a lubricating oil

supplied between them, and wherein the eccentric sleeve

bearing has a robust region in a change of a minimum oil

film thickness of the lubricating oil with respect to a

change of a motor power which rotationally drives the main

shaft.

[0035] A gyration-type crusher according to a thirteenth aspect of the present invention comprises: a main shaft which is rotatably arranged inside a conecave and which makes an eccentric rotary movement with its center axis inclined with respect to a center axis of the conecave; a mantle provided on the main shaft; an eccentric sleeve having a main shaft fitting insertion hole into which a lower end portion of the main shaft is rotatably inserted; an outer cylinder having an eccentric sleeve fitting insertion hole into which the eccentric sleeve is rotatably inserted, wherein an outer peripheral surface of the lower end portion of the main shaft which is inserted into the main shaft fitting insertion hole and a surface which forms the main shaft fitting insertion hole form a main shaft bearing with a lubricating oil supplied between them, wherein an outer peripheral surface of the eccentric sleeve which is inserted into the outer cylinder and a surface which forms the eccentric sleeve fitting insertion hole form an eccentric sleeve bearing with a lubricating oil supplied between them, and wherein in at least one of the main shaft bearing and the eccentric sleeve bearing, when the motor power which rotationally drives the main shaft changes from about 50% to about 160% of the rated value, a surface pressure distribution of the lubricating oil changes from a bearing lower portion to a bearing upper portion.

[0036] A gyration-type crusher according to a fourteenth

aspect of the present invention comprises: a main shaft which is rotatably arranged inside a conecave and which makes an eccentric rotary movement with its center axis inclined with respect to a center axis of the conecave; a mantle provided on the main shaft; an eccentric sleeve having a main shaft fitting insertion hole into which a lower end portion of the main shaft is rotatably inserted; and an outer cylinder having an eccentric sleeve fitting insertion hole into which the eccentric sleeve is rotatably inserted, wherein an outer peripheral surface of the lower portion of the main shaft which is inserted into the main shaft fitting insertion hole and a surface which forms the main shaft fitting insertion hole form a main shaft bearing with a lubricating oil supplied between them, wherein an outer peripheral surface of the eccentric sleeve which is inserted into the outer cylinder and a surface which forms the eccentric sleeve fitting insertion hole form an eccentric sleeve bearing with a lubricating oil supplied between them, and wherein in at least one of the main shaft bearing and the eccentric sleeve bearing, when the motor power which rotationally drives the main shaft changes from about 50% to about 160% of the rated value, a surface pressure distribution of the lubricating oil changes from a bearing lower portion to entire bearing vertical direction.

[0037] A fifteenth aspect of the present invention is a

gyration-type crusher further comprising, in any one of the

first to the fourteenth aspects, an upper bearing, wherein

an upper end portion of the main shaft is rotatably supported by the upper bearing.

[0038] A sixteenth aspect of the present invention is that,

in the fifteenth aspect, the gyration-type crusher is a

primary crusher or a secondary crusher including both

primary and secondary.

[0039] A seventeenth aspect of the present invention is

that, in any one of the first to the sixteenth aspects, as

an operation continues, an unique sliding mark which cannot

be generated in a gyration-type crusher without the robust

region is formed on a bearing.

[0040] An eighteenth aspect of the present invention is

that, in the seventeenth aspect, the unique sliding mark is

formed at least in a lower portion of the bearing.

[0041] A nineteenth aspect of the present invention is that,

in the eighteenth aspect, the unique sliding mark is formed

only in a lower portion of the bearing as an operation

continues, and then formed entirely from a lower portion to

an upper portion of the bearing.

[0042] A twentieth aspect of the present invention is that,

in the nineteenth aspect, the unique sliding mark is formed

only in a lower portion of the bearing as an operation

continues, then formed entirely from a lower portion to an

upper portion of the bearing, and then formed only in an

upper portion of the bearing.

[0043] According to at least some aspects or embodiments

of the present invention, it is possible to provide a

gyration-type crusher which can cope with a variety of objects to be crushed robustly and can also cope with changes in load conditions robustly.

Brief Description of Drawings

[0044]

Preferred embodiments of the present invention are

hereinafter described, by way of example only, with

reference to the accompanying drawings, in which:

FIG. 1 is a longitudinal section view illustrating

the whole structure of one example of a gyration-type

crusher.

FIG. 2 is a plan view for explaining the principle of

crushing with a gyration-type crusher.

FIG. 3 schematically illustrates aspects of the

bearing of the gyration-type crusher according to one

embodiment of the present invention, classifying the

relationship between the contact state of the bearing 15

(main shaft bearing 10 or eccentric bearing 11) and the

minimum oil film thickness into three states depending on

the magnitude of the crushing load; (a) illustrates the

lower contact state, (b) illustrates the even contact state,

and (c) illustrates the upper contact state.

FIG. 4 is an enlarged longitudinal section view of

the bearing 15, illustrating the relationship between a

center axis Li of the main shaft 5, a center axis L2 of the

upper frame 1, a center axis L3 of the main shaft insertion

hole 3, a center axis L4 of the eccentric sleeve 4, and a center axis L5 of the eccentric sleeve insertion hole 27.

FIG. 5 is a graph illustrating the change of the

minimum oil film thickness of the bearing with respect to

the change of the crushing load, regarding the bearing 15

of specification A.

FIG. 6 is a graph illustrating the change of the

inclination angle of the axis with respect to the change of

the crushing load, regarding the bearing 15 of

specification A.

FIG. 7 is a graph illustrating the change of the

minimum oil film thickness of the bearing with respect to

the change of the crushing load, regarding the bearing 15

of specification B.

FIG. 8 is a graph illustrating the change of the

inclination angle of the axis with respect to the change of

the crushing load, regarding the bearing 15 of

specification B.

FIG. 9 illustrates the oil film pressure distribution

of the bearing 15 in the upper contact state.

FIG. 10 illustrates the oil film pressure

distribution of the bearing 15 in the even contact state,

regarding the bearing with the same crushing load and

specification as in FIG. 9.

FIG. 11 illustrates summary of comparison of the

change of minimum oil film thickness ((a)) and the change

of inclination angle ((b)) with respect to the change of

crushing load in a bearing with robust characteristic and a bearing without robust characteristic.

FIG. 12 is a graph illustrating the schematic

characteristic curve illustrating the robust characteristic

regarding the bearing 15 of specification A.

FIG. 13 is a graph which approximates the robust

characteristic curve illustrated in FIG. 12 with a

quadratic function.

FIG. 14 is a graph which approximates the robust

characteristic curve illustrated in FIG. 12 with a cubic

function.

FIG. 15 is a graph illustrating the schematic

characteristic curve illustrating the robust characteristic

regarding the bearing 15 of specification B.

FIG. 16 is a graph which approximates the robust

characteristic curve illustrated in FIG. 15 with a

quadratic function.

FIG. 17 is a graph which approximates the robust

characteristic curve illustrated in FIG. 15 with a cubic

function.

Detailed Description

[0045] Hereunder, one embodiment of the gyration-type crusher according to the present invention will be described referring to the drawings.

[0046] The basic configuration of the gyration-type crusher

according to this embodiment has the same configuration as

in FIG. 1. Hereunder, the same configuration will be

described using the same reference numerals and the like as

those of the conventional one, and different portions will

be mainly described. Therefore, the matters not described

are the same as those of the conventional gyration-type

crusher unless there is a particular contradiction.

Moreover, in the embodiment below, a hydraulic cone crusher

will be described as an example in order to correspond to

FIG. 1, while it goes without saying that the gyration-type

crusher according to the present embodiment is not limited

to a cone crusher including the hydraulic cone crusher, and

can be applied to a gyratory crusher and other types.

[0047] In the hydraulic cone crusher according to this

embodiment, the main shaft 5 whose center axis is inclined

relative to the center axis of the crusher is provided in

the center of the internal space formed of the upper frame

1 in the shape of a truncated inverted substantial conical

tubular body and the lower frame 2 connected thereto.

[0048] In the main shaft 5, the lower end portion is

rotatably inserted into the main shaft fitting insertion

hole 3 formed in the eccentric sleeve 4, and the gap

between the outer peripheral surface of the main shaft 5

inserted into the main shaft fitting insertion hole 3 and the inner peripheral surface of the eccentric sleeve 4 configures a radial slide bearing (main shaft bearing 10) holding a predetermined gap to which lubricating oil is supplied and an oil film is formed.

[0049] Further, the eccentric sleeve 4 is rotatably

inserted into the outer cylinder 7 disposed in the lower

frame 2, and the gap between the outer peripheral surface

of the eccentric sleeve 4 and the inner peripheral surface

of the outer cylinder 7 configures a journal bearing

(radial slide bearing) (eccentric sleeve bearing 11)

holding a predetermined gap to which lubricating oil is

supplied and an oil film is formed. Note that, hereunder,

for convenience of explanation, the main shaft bearing 10

and the eccentric sleeve bearing 11 may be referred to as

the bearing 15 by abstraction without particularly

distinguishing them.

[0050] Hereunder, the configuration of the bearing 15 in

the embodiment of the present invention will be described

in detail.

[0051] The state of the bearing 15 changes as the main

shaft 5, the frame 31, and the like are displaced and

deformed due to the change of crushing load and thereby

reaction force by changing the type and properties

(material, size, moisture content, and the like) of the

object to be crushed and operating conditions (rotation

speed, input amount of object to be crushed, and the like).

[0052] That is, the bearing 15 may be roughly divided into three states illustrated in FIG. 3 due to the change of crushing load caused by the change of the type and properties of the object to be crushed.

[0053] FIG. 3 is a diagram schematically illustrating the

relationship between the one side contact and the minimum

oil film thickness T, classified into three states

depending on the magnitude of the bearing load F, which

changes according to the magnitude of the crushing load W,

in order to extract and explain the operation and behavior

of the bearing 15: (a) illustrates the lower contact state

in which the center axis La of the shaft 41 is inclined to

the left (in the page) with respect to the center axis Lb

of the inner peripheral surface of the bearing 15, (b)

illustrates an almost even contact state in which the

center axis La of the shaft 41 and the center axis Lb of

the inner peripheral surface of the bearing 15, and (c)

illustrates the upper contact state in which the center

axis La of the shaft 41 is inclined to the right (in the

page) with respect to the center axis Lb of the inner

peripheral surface of the bearing 15. Note that the

bearing load F increases and decreases according to the

increase and decrease of the crushing load W. Note that

the minimum oil film thicknesses in the lower contact state,

even contact state, and upper contact state are Ti, T2, and

T3, respectively.

[0054] Here, the main shaft bearing 10 and the eccentric

sleeve bearing 11 will be individually described as follows.

[00551 In FIG. 3, when the bearing 15 is the main shaft

bearing 10, the shaft 41 is the main shaft 5 (refer to FIG.

4), and based on the state where the center axis Li of the

main shaft 5 is substantially parallel to the center axis

L3 of the main shaft fitting insertion hole 3, and

approaches the right inner surface side (in the page) of

the main shaft fitting insertion hole 3, and an oil film

with a substantially even thickness is formed over the

entire axial direction (even contact state) (FIG. 3 (b)),

when the bearing load F is smaller than the bearing load Fo

in the even contact state, the displacement and deformation

of the main shaft 5 and the like are small, and therefore

the center axis Li of the main shaft 5 is inclined to the

left (in the page) with respect to the center axis L3 of

the main shaft fitting insertion hole 3 to be in the lower

contact state (FIG. 3(a)). In contrast, when the bearing

load F is larger than the bearing load Fo in the even

contact state, the displacement and deformation of the main

shaft 5 and the like are large, and therefore the center

axis Li of the main shaft 5 is inclined to the right (in

the page) with respect to the center axis L3 of the main

shaft fitting insertion hole 3 to be in the upper contact

state (FIG. 3(c)).

[0056] Here, since the main shaft 5 is pressed by the

bearing load F toward the inner peripheral direction of the

frame 31 (right direction of the page in FIG. 3), and moves

due to displacement and deformation, the region where the minimum oil film thickness occurs is generally on the inner peripheral side of the frame 31 in the main shaft bearing

10. Thereby, as illustrated in FIG. 3, the positions where

the minimum oil film thickness occurs in the main shaft

bearing 10 in the lower contact state, the even contact

state, and the upper contact state are the lower end

portion, the entire axis direction (substantially even),

and the upper end portion, respectively on the side

opposite to the side on which the bearing load F acts, and

the size of the minimum oil film thickness T decreases in

the order of the lower contact state, the even contact

state, and the upper contact state.

[0057] Further, in FIG. 3, when the bearing 15 is the

eccentric sleeve bearing 11, the shaft 41 is the eccentric

sleeve 4 (refer to FIG. 4), as with the main shaft bearing

10, when the bearing load F is small, the center axis L4 of

the eccentric sleeve 4 is inclined to the left (in the

page) with respect to the center axis L5 of the eccentric

sleeve fitting insertion hole 27 to be in the lower contact

state (FIG. 3(a)). In contrast, when the bearing load F is

large, the center axis L4 of the eccentric sleeve 4 is

inclined to the right (in the page) with respect to the

center axis L5 of the main shaft fitting insertion hole 3

to be in the upper contact state (FIG. 3(c)). When the

magnitude of the bearing load F is in the middle between in

the lower contact state and the upper contact state, the

center axis L4 of the eccentric sleeve 4 is substantially parallel to the center axis L5 of the main shaft fitting insertion hole 3, and approaches the right inner surface side (in the page) of the main shaft fitting insertion hole

3, and an oil film with a substantially even thickness is

formed (even contact state) (FIG. 3 (b)).

[0058] Here, in the eccentric sleeve bearing 11, the

positions where the minimum oil film thickness occurs in

the lower contact state, the even contact state, and the

upper contact state and the size of the minimum oil film

thickness T are the same as in the main shaft bearing 10.

[0059] Note that, in the FIG. 3 and FIG. 4, for ease of

understanding, the gap between the outer peripheral surface

of the main shaft 5 and the inner peripheral surface of the

eccentric sleeve 4 and the gap between outer peripheral

surface of the eccentric sleeve 4 and the inner peripheral

surface of the outer cylinder 7 are exaggerated and drawn

large.

[0060] Table 1 summarizes the above three states of the

bearing 15 according to the difference in the magnitude of

the crushing load.

[0061] [Table 1]

Crushing load small medium large

Bearing load F small medium large

Inclination angle of La <0 .0 >0

with respect to Lb

Contact state lower substantially upper

contact even contact

Minimum oil film large medium small

thickness T

[0062] Regarding the design range for the bearing 15 as

shown in FIG. 3 in the gyration-type crusher, in general,

when the L/ D is in the range of about 0.5 to 2, the order

of the Sommerfeld number S, which is an evaluation index

representing the oil film characteristic of the fluid

lubricated bearing, is about 0.0001 to 0.1, and the minimum

oil film thickness is about several pm to several hundred

pm. Here, L and D are the bearing length and the shaft

diameter, respectively. The Sommerfeld number S is a

dimensionless quantity for evaluating the lubrication state

of the sliding bearing and the shaft lubricated with oil or

the like (fluid lubrication), and is calculated by the

following equation (1).

[0063] S=(7)n/P) (r/c) 2

[0064] Here, ) is viscosity coefficient of lubricating oil

[P=10-'Pa-s], n is shaft rotation speed [s-1], P is bearing

surface pressure [Pa], r is shaft diameter [m], c (= R-r,

R: bearing radius, r: shaft radius) is bearing clearance

[m].

[0065] Based on the above, the relationship between the

minimum oil film thickness and the inclination angle for

the crushing load obtained by analysis will be described

for the case where the bearing 15 is specification A (L/D =

about 1.4, Sommerfeld number S = about 0.001) and

specification B (L/D = about 0.8, Sommerfeld number S = about 0.01).

[00661 FIG. 5 is a graph illustrating the change of the

minimum oil film thickness of the bearing 15 with respect

to the change of the crushing load, in which deformation

and displacement of structures such as the main shaft 5 and

the frame 31 (upper frame 1 and lower frame 2) are obtained

by structural analysis such as FEM (finite element method)

and BEM (boundary element method), and further using these

values, the oil film thickness of the bearing 15 of

specification A is obtained by oil film analysis using the

Reynolds equation based on the fluid lubrication theory and

then arranged. FIG. 6 is a graph illustrating the change

of the inclination angle of the bearing 15 of specification

A with respect to the change of the crushing load. Further,

FIG. 7 is a graph illustrating the change of the minimum

oil film thickness of the bearing 15 of specification B

with respect to the change of the crushing load, in which

deformation and displacement of structures such as the main

shaft 5 and the frame 31 are obtained by structural

analysis such as FEM, and further using these values, the

oil film thickness of the bearing 15 of specification B is

obtained by oil film analysis using the Reynolds equation

based on the fluid lubrication theory and then arranged.

FIG. 8 is a graph illustrating the relationship between the

crushing load and the inclination angle of the bearing 15

of specification B.

[0067] Here, for the structural analysis and the oil film analysis, it is desirable to apply a method which is validated in comparison with the bearing state (sliding marks, and the like) in the experimental machine and the achievement machine, respectively. Note that, in the oil film analysis, an analysis method considering the deformation and inclination of the shaft and the bearing is used. In addition, ideally, a bi-directional coupled analysis method is desired for the structural analysis and oil film analysis, while in general, so-called unidirectional coupled analysis in which the oil analysis is performed using the result of the structural analysis as described above is practical.

[0068] In the validity evaluation of the above analysis

method, a method of comparing the one side contact state

(contact surface pressure distribution), the minimum oil

film thickness, and the like obtained from the analysis

with the sliding marks obtained by operating the actual

machine is effective.

[0069] Note that, in FIG. 5 to FIG. 8, the crushing load

on the horizontal axis is normalized where the rated load

is 100%.

[0070] Here, regarding the rated load, in the gyration-type

crusher which can be operated at the rated output of the

electric motor which drives the gyration-type crusher, the

crushing load which can be generated by the gyration-type

crusher with the input material (for example rocks) being

crushed at the rated output is regarded as the rated output, or in the gyration-type crusher in which the crushing load which can occur when crushing at the rated output of the electric motor exceeds the upper limit of the load that the main body of the gyration-type crusher or a part of the component device can withstand continuously, the maximum output which can safely continue the crushing process is regarded as the rated output, and the crushing load corresponding to the output is called the rated load.

[0071] Note that the cone crusher is generally designed

assuming the state where continuous crushing continues,

while the gyratory crusher used in a primary crusher or the

like may regularly perform single particle crushing or

discontinuous crushing of a large raw material (such as

stone, specifically) in addition to the state where

continuous crushing continues. However, even in a

gyration-type crusher operated like the gyratory crusher,

the rated load is as defined above.

[0072] Further, the minimum oil film thickness on the

vertical axis in FIG. 5 and FIG. 7 is normalized where the

minimum oil film thickness of the bearing 15 is 1 when the

crushing load is 100%.

[0073] Further, the inclination angle of the vertical axis

in FIG. 6 and FIG. 8 is normalized where the direction that

the shaft 41 is inclined to the right (in the page) with

respect to the center axis L2 of the bearing 15 (direction

toward upper contact) is the positive direction, and the

absolute value of the inclination angle when the crushing load is 50% is 1. As for the positive / negative sign related to the normalized inclination angle, negative (-) indicates the lower contact state and positive indicates the upper contact state.

[0074] Regarding the bearing 15, the inclination angle

generally increases monotonously with a substantially

linear or gentle curve with respect to the increase in

crushing load, as illustrated in FIG. 6 and FIG. 8. In

contrast, regarding the bearing 15, the minimum oil film

thickness generally decreases almost monotonically overall

with respect to the increase in crushing load, as

illustrated in FIG. 5 and FIG. 7. While, in a certain

range of the crushing load, a decrease (change) rate with

respect to the increase in crushing load is smaller than in

a range other than the certain range. Specifically, in the

bearing 15 of specification A. Specifically, in the

bearing 15 of specification A illustrated in FIG. 5, the

minimum oil film thickness decreases as the crushing load

increases from 50%, but as the crushing load increases, the

rate of change (generally a decrease) in the minimum oil

film thickness continuously becomes gentle. The tendency

continues until the rate of decrease in minimum oil film

thickness with respect to the increase in crush load

increases rapidly at the crush load of about 105%. In the

bearing 15 of specification B illustrated in FIG. 7, the

minimum oil film thickness decreases as the crushing load

increases from 50%, but as the crushing load increases, the rate of change (generally a decrease, described later in detail) in the minimum oil film thickness continuously becomes gentle. The tendency continues until the rate of change of minimum oil film thickness with respect to the increase in crush load increases rapidly at the crush load of about 145%.

[0075] As above, a specific range in which the decrease

(change) rate of the minimum oil film thickness with

respect to an increase in crushing load is smaller than the

other ranges and before the rate of change of the minimum

oil film thickness increases rapidly is referred to as a

"robust region", in this description. Additionally, the

property of the bearing 15 having the robust region is

referred to as "robust characteristic". Generally, the

change of the minimum oil film thickness with respect to

the crushing load gradually shifts from when the crushing

load is small up to the upper limit value of the robust

region, as illustrated in FIG. 5 and FIG. 7. Therefore, in

many cases, the lower boundary (lower limit value) of the

robust region cannot be clearly specified. In contrast, as

described above, the upper boundary (upper limit value) of

the robust region is specified by the feature that the

ratio of the decrease in the minimum oil film thickness

with respect to the increase in the crushing load, which

has been moderate until then, rapidly increases.

Specifically, for example, about 105% of the crushing load

in the bearing 15 of specification A and about 145% in the specification B are the upper limit values of the respective robust regions. Note that, a mathematical method for specifying the upper limit value will be described later.

[0076] The inclination angle of the bearing 15 changes from

negative to positive at about 100% of the crushing load in

the specification A according to FIG. 6, and at about 145%

of the crushing load in the specification B according to

FIG. 8. Accordingly, in the specification A, when the

crushing load is about 105%, the substantially even contact

state is obtained, and when the crushing load is less than

about 105%, the lower contact state is obtained, and when

it is greater than about 105%, the upper contact state is

obtained. In the specification B, when the crushing load

is about 145%, the substantially even contact state is

obtained, and when the crushing load is less than about

145%, the lower contact state is obtained, and when it is

greater than about 145%, the upper contact state is

obtained.

[0077] As described above for the inclination angle in the

bearing 15, the reason why the bearing 15 of the gyration

type crusher according to this embodiment has the

characteristic that it goes to the upper contact state as

the crushing load increases and it goes to the lower

contact state as the crushing load decreases is that,

mainly, the main shaft 5 is deformed (elastically) by the

bearing load F acting on the middle portion of the bearing

15 which is the lower bearing and the upper bearing 17 as

supporting points, whereby the local contact position of

the shaft 41 with respect to the bearing 15 shifts from the

lower end portion of the bearing 15 to the upper end

portion.

[0078] The elastic deformation and displacement of the main

shaft 5 strongly depend on the bending rigidity of the main

shaft determined from the distance between the bearing

centers of the upper bearing 17 and the bearing 15 (main

shaft bearing 10 or eccentric sleeve bearing 11), the

diameter of the main shaft 5, and the like. Here, for the

same crushing load, for example, when the distance between

the bearing centers of the upper bearing 17 and the lower

bearing (bearing 15) increases, the deformation and

displacement of the main shaft 5 increase. Further, for

example, when the diameter of the main shaft 5 of the

portion inserted into the main shaft fitting insertion hole

3 or the diameter of the bottom surface of the mantle 13

increases, the deformation and displacement of the main

shaft 5 decrease.

[0079] Therefore, in the gyration-type crusher, in general,

the lower bearing 15 structurally tends to be in the upper

contact state. Therefore, when seizure occurs in the lower

bearing 15, it is generally in the upper contact state. In

particular, in a gyration-type crusher used as a primary

crusher or a secondary crusher, the distance between the

bearing centers with respect to the diameter of the main shaft is structurally long, and the bearing 15 tends to be in the strong upper contact state as the crushing load increases.

[0080] In contrast, as the crushing load (reaction force)

increases and the displacement and deformation of the main

shaft 5, the frame 31, and the like increase, it shifts to

the upper contact state through the even contact state, and

the minimum oil film thickness decreases (refer to Table 2).

As a result, in the upper contact state, the oil film

pressure of the bearing 15 has a distribution having a peak

at the upper end portion, as illustrated in FIG. 9.

[0081] As above, when the bearing 15 which is the lower

bearing shifts from the lower contact state to the upper

contact state, in the bearing 15 which is the lower bearing,

the support point (reaction point) which receives the

reaction force of the crushing load acting on (the middle

part of) the main shaft 5 changes from the lower end

portion to the upper end portion of the bearing 15, and

therefore the distance between the action point of the main

shaft 15 where the reaction force of the crushing load acts

and the support point of the bearing 15 is shortened. As

a result, in the upper contact state, the bearing load

acting on the bearing 15 tends to be larger than in the

bottom contact state and the substantially even contact

state, even if the reaction force of the crushing load

acting on the main shaft 5 is the same, and this is a

severe condition for the bearing.

[0082] Here, for comparison, the oil film pressure

distributions in the one side contact state and the even

contact state are analyzed using bearings having the same

bearing load and specification, and the results are

illustrated in FIG. 9 and FIG. 10, respectively. Note that

the inclination angles of the shaft 41 in FIG. 9 and FIG.

are 0.015 degrees and 0 degrees, respectively, and the

scale of pressure distribution is the same.

[0083] From FIG. 9 and FIG. 10, the pressure distribution

in the even contact state does not have a prominent peak in

the axis direction, and has a low and gentle distribution

as a whole.

[0084] In at least one of the bearing 15, that is, the main

shaft bearing 10 and the eccentric sleeve bearing 11, the

contact state of the bearing changes from the lower contact

state to the substantially even contact state when the

power of the motor which rotationally drives the main shaft

5 increases and the crushing load changes from the lower

limit value to the upper limit value of the robust region.

Therefore, the position at which the oil film thickness of

the lubricating oil is minimum changes from the lower end

side of the bearing to the entire bearing vertical

direction. At this time, the oil film pressure

distribution of the bearing changes from a state biased

toward the lower end side of the bearing so as to approach

the smoothness as a whole over the vertical direction of

the bearing along with the change from the lower contact state to the substantially even contact state.

[0085] When the crushing load further increases and the

crushing load exceeds the upper limit value of the robust

region, the contact state between the shaft 15 and the

bearing 41 changes to the upper contact state. As a result,

the position where the oil film thickness is minimum moves

to the upper end side of the bearing 15. Further, the oil

film pressure distribution changes from a smooth

distribution over the vertical direction of the bearing to

a steep pressure distribution biased toward the upper end

portion of the bearing along with the change from the

substantially even contact state to the upper contact state.

[0086] Note that the minimum oil film thickness in the one

side contact state of FIG. 9 is reduced to about 13% of the

minimum oil film thickness in the even contact state of FIG.

10. Thus, under the same load condition and specification,

from the viewpoint of the minimum oil film thickness,

generally the substantially even contact state is

advantageous in oil film formation. On the contrary, since

the minimum oil film thickness becomes small in the one

side contact state, particularly in the upper contact state,

it is a severe condition for the bearing.

[0087] However, in the process in which the bearing 15

gradually changes from the slight lower contact state to

the substantially even contact state along with the

increase in crushing load, the bearing 15 has a feature

that it has a robust region, and the change of the minimum oil film thickness with respect to the change of the crushing load is secured in a less sensitive state compared to out of the robust region, so that the minimum oil film thickness is easily secured.

[0088] Hereunder, the feature of the bearing having robust

characteristic will be described in detail.

[0089] FIG. 11 illustrates a comparison of the change of

minimum oil film thickness ((a)) and the change of

inclination angle ((b)) with respect to the change of

crushing load in a bearing without robust characteristic

and a bearing with robust characteristic. Here, in FIG. 11,

the crushing load is normalized where the rated load is

100%, the minimum oil film thickness is normalized where

the minimum oil film thickness when the crushing load is

100% of the rated load is 1, and the inclination angle is

normalized where the absolute value of the inclination

angle when the crushing load is 20% of the rated load is 1.

Additionally, for ease of explanation and understanding,

the minimum oil film thickness and the inclination angle

are expressed in a simplified manner. Note that, for the

range of the robust region in a bearing with robust

characteristic, the upper limit value of the robust region

of the bearing with robust characteristic is set to 120% of

the crushing load, for ease of understanding of the

difference between with and without robust characteristic,

and the like.

[0090] In the gyration-type crusher, for example, when crushing operation is performed with the crushing load set to the rated load, the magnitude of the crushing load during operation varies due to variations in the charge amount, shape / size, property, and the like of the raw material charged into the crushing chamber 16. Therefore, for example, if the crushing load increases by 5% with respect to the rated load, the inclination angle of both the bearing without robust characteristic and the bearing with robust characteristic increases accordingly, and they shift to the one side contact (upper contact) state (FIG.

11 (b)). As for the inclination angle, the bearing without

robust characteristic is in the upper contact state when

the crushing load is 50% or more. On the other hand, the

bearing with robust characteristic is in the lower contact

state when the crushing load is 50%, and shifts to a

completely even contact state when the crushing load is

120%, and in the upper contact state when the crushing load

exceeds that.

[0091] The minimum oil film thickness of both the bearing

without robust characteristic and the bearing with robust

characteristic generally decreases almost monotonically

along with the increase in crushing load. The bearing

without robust characteristic is already in the upper

contact state when the crushing load is 50%, and the

inclination angle increases when the crushing load exceeds

that, and the minimum oil film thickness decreases

monotonically along with the shift to the strong upper contact state. In contrast, the bearing with robust characteristic exhibits a so-called robust characteristic in which the minimum oil film thickness decreases as the crushing load increases from 50%, but as the crushing load increases, the rate of change (generally decrease)in the minimum oil film thickness continuously becomes gradual, and the tendency continues until the rate of decrease in minimum oil film thickness with respect to the increase in crushing load increases rapidly at the crushing load of about 105%. In the example of FIG. 11, particularly when the crushing load is in the range of about 80% to 120%, the decrease (change) rate with respect to the increase

(change) in crushing load is smaller compared to the range

other than the range, which exhibits typical robust

characteristic. Rewording that associating the change of

crushing load with the state of one side contact state of

the bearing, in a range from the slight lower contact state

to the substantially even contact state, the robust

characteristic is exhibited for the minimum oil film

thickness.

[0092] Therefore, it can be seen that the gyration-type

crusher can have the robust characteristic by adjusting the

one side contact state and the transition point of the one

side contact state, and in the robust region, the bearing

can secure the stability of the oil film characteristic

with respect to the fluctuation of the crushing load, which

can be very effective from the viewpoint of appropriately securing an oil film.

[0093] Note that, as described above, the robust region is

formed in a range from the slight lower contact state to

the substantially even contact state. In the case of

without robust region in FIG. 11, the bearing which always

has only the upper contact state as a range is exemplified.

However, even a bearing which does not include the slight

lower contact state and has the relatively strong lower

contact state as a range does not have the robust region as

well.

[0094] Note that, in the bearing which has the robust

characteristic, the ratio of the change of minimum oil film

thickness with respect to the change of crushing load is

the most insensitive (smallest) at the upper limit value of

the robust region or a crushing load slightly smaller than

the upper limit value. Although, in general, the change of

the minimum oil film thickness with respect to the crushing

load is monotonous decrease, the rate of change may be 0

(zero) at a crushing load slightly smaller than the upper

limit value of the robust region. In such cases, the

minimum oil film thickness increases slightly along with

increase in crushing load between the load and the upper

limit value of the robust region, and when the crushing

load exceeds the upper limit value, the minimum oil film

thickness may start to decrease again along with increase

in crushing load. However, since this behavior is small

and may occur only under limited conditions, there is no problem considering that the minimum oil film thickness change with respect to the crushing load generally decreases monotonously.

[0095] Due to the difference in the minimum oil film

thickness depending on the presence or absence of the

robust characteristic as described above, a difference in

sliding mark occurs between the bearing with the robust

characteristic and the bearing without the robust

characteristic. Hereunder, the difference in the sliding

marks between the two will be described.

[0096] In a general gyration-type crusher, if the shaft,

bearing and lubricant are sound, there occurs no immediate

seizure due to sliding with slight contact thanks to the

effects of the material properties of the bearing, the

extreme pressure additive in the lubricating oil, and the

like. However, when the bearing experiences slight contact,

a desirable crowning is formed naturally in the vicinity of

the bearing end, or unevenness of the surface is smoothed

on the bearing surface, whereby the bearing is modified so

that it functions soundly even with a stronger one side

contact and a thinner oil film than in a new state. This

is a phenomenon generally called "break-in" or "run-in". In

the process, some kind of sliding marks are formed on the

surfaces of the shaft and the bearing. However, even when

a sound bearing oil film is formed, if foreign matter of a

size or amount that is not negligible with respect to the

oil film thickness is mixed into the lubricating oil, sliding marks such as a linear mark and a polishing mark, and a foreign matter biting mark are formed.

[0097] As described above, the bearing 15 has the robust

characteristic related to the minimum oil film thickness in

a range from the slight lower contact state to the

substantially even contact state when focusing on its one

side contact state and transition point.

[0098] Therefore, in the range of the robust region, a

relatively wide and smooth sliding mark is formed instead

of a local and strong sliding mark. Further, when the

sliding mark formed in the robust region is due to delicate

foreign matter in the lubricating oil, the foreign matter

acts like an abrasive, and the sliding mark (polishing

mark) is formed in a relatively wide range.

[0099] In the case when such a sliding mark is formed, when

the bearing is in the slight lower contact state, the

minimum oil film is formed at the lower end portion of the

bearing and the oil film thickness gradually changes

(generally decreases) as it goes upward, and therefore the

sliding mark is likely to be formed in a wide range

extending from the position of about one fifth to one third

of the axis length to the lower region with the lower end

of the bearing 15 as a reference. Further, when the

bearing is in the substantially even contact state, the

inclination angle fluctuates around the even contact state

with respect to the fluctuation in crushing load, and

therefore the sliding mark is formed around the center portion in the axis direction. Accordingly, the continuous sliding mark is formed over a wide range between the position of about one fifth to one third of the axis length with the lower end of the bearing 15 as a reference and the position of about one fifth to one third of the axis length with the upper end of the bearing 15 as a reference.

Further, when the bearing 15 shifts from the substantially

even contact state to the upper contact state, the bearing

15 exceeds the upper limit of the robust region and the

robust characteristic is lost. When the bearing shifts to

the upper contact state as above, contrarily, the minimum

oil film is formed at the upper end portion of the bearing

and the oil film becomes thick as it goes downward. As a

result, the sliding mark in the upper contact state is

formed in a wide range extending from the position of about

one fifth to one third of the axis length to the upper

region with the upper end of the bearing 15 as a reference.

[0100] Therefore, when the bearing 15 has the robust region

and it exceeds the upper limit value and shifts to the

upper contact state, there are formed the sliding mark in

the upper contact state in a range above the position of

about one fifth to one third of the axis length with the

upper end of the bearing 15 as a reference, and the sliding

mark continuous over a wide range between the position of

about one fifth to one third of the axis length with the

lower end of the bearing 15 as a reference and the position

of about one fifth to one third of the axis length with the upper end of the bearing 15 as a reference.

[0101] From the above, in the bearing with the robust

characteristic, due to the fluctuation in crushing load and

the like, seizure due to a loss of oil film or the like

hardly occurs, and the smooth sliding mark tends to be

formed in a relatively wide range in the axis length

direction. Note that, when the bearing having the upper

limit value and the lower limit value of the robust

characteristic changes in the one side contact state

according to the crushing load, the minimum oil film

thickness T2 in the substantially even contact state and

the minimum oil film thickness Ti in the lower contact

state is larger than the minimum oil film thickness T3 in

the upper contact state. As a result, compared with the

upper contact state, the oil film state is improved, and

the sliding mark itself is hardly formed in the slight

lower contact state and the substantially even contact

state. Therefore, even with the robust region, the sliding

mark at the position of about one fifth to one third of the

axis length with the lower end of the bearing 15 as a

reference described above may be relatively slight or not

formed.

[0102] In contrast, outside the range of the robust region,

the bearing is in the lower contact state or upper contact

state with a relatively strong inclination. In the lower

contact state which is outside the robust region, a local

sliding mark is formed near the lower end portion of the bearing. In the upper contact state, the sliding mark is formed above the position of about one fifth to one third of the axis length with the upper end of the bearing as a reference. Note that, in the bearing in the upper contact state outside the robust region, when the crushing load is further increased, the minimum oil film thickness decreases rapidly as the upper contact progresses. As a result, a strong sliding mark is likely to be formed locally, and further, in addition to the sliding mark, seizure may occur due to an oil film defect and the like.

[0103] The bearing without the robust characteristic is a

bearing having a range of the upper contact state, or a

bearing having a range of the lower contact state with a

relatively strong inclination. In other words, it is a

bearing not having a range of the slight lower contact

state and the substantially even contact state. Therefore,

such a bearing has only one of the features of the sliding

mark outside the range of the robust region above, and does

not form a specific sliding mark when it has the robust

region.

[0104] When the oil film thickness is sufficiently thick,

or foreign matters having a size or amount which cannot be

ignored with respect to the oil film thickness do not enter

the lubricating oil, generally, the sliding mark is not

formed. Therefore, in such a bearing, the presence or

absence of the robust region cannot be judged from the

sliding mark. While, when the sliding mark resulting from the robust region above is observed, it can be determined that there is the robust region.

[0105] Note that, in FIG. 11 (a), the minimum oil film

thickness is normalized and therefore the normalized

minimum oil film thickness is the same for the bearing with

the robust characteristic and the bearing without robust

characteristic. However, considering the change rate of

the minimum oil film thickness with respect to the change

of crushing load in the bearing without robust

characteristic, the actual minimum oil film thickness at

the rated load is larger in the bearing without robust

characteristic.

[0106] A method for specifying the upper limit value of the

robust region in the bearing with robust characteristic

will be described.

[0107] As explained for FIG. 5 and FIG. 7 above, in the

bearing with robust characteristic, the change of the

minimum oil film thickness with respect to the crushing

load clearly changes before and after the upper limit value

of the robust region. The black circles (*) in FIG. 5 and

FIG. 7 indicate the values obtained by the oil film

analysis, and the solid line is obtained by connecting the

black circles with straight lines. Regarding the bearing

with robust characteristic, it is easy to specify the upper

limit value of the robust region if the minimum oil film

thickness is analyzed at many crushing load points as

illustrated in FIG. 5 and FIG. 7. In FIG. 5, about 105% can be determined as the upper limit value, and in FIG. 7, about 145% can be determined as the upper limit value.

[0108] Using mathematical methods, the robust

characteristic can be approximated by two approximate

curves, specifically, curves of a quadratic or cubic

function, for example. Further, the upper limit value of

the robust region can be identified from the intersection

of these two approximate curves. FIG. 13 and FIG. 14

illustrate cases where the robust characteristic of the

bearing specification A (FIG. 5) illustrated in FIG. 12 is

approximated by curves of quadratic and cubic functions,

respectively. By obtaining the intersection of the

respective approximate curves, the upper limit value of the

robust characteristic is specified as 104.7% in the

approximation of FIG. 13 and 105.1% in the approximation of

FIG. 14. Similarly, FIG. 16 and FIG. 17 illustrate cases

where the bearing specification B (FIG. 7) illustrated in

FIG. 15 is approximated by curves of quadratic and cubic

functions, respectively. The upper limit value of the

robust characteristic is specified as 144.1% in FIG. 16 and

145.4% in FIG. 17.

[0109] The above example is a case where the robust

characteristic is relatively clear. When the difference

between the change rate of the minimum oil film thickness

with respect to the change of crushing load in the robust

region and the change rate outside the range of the robust

region is small, the robust region is unclear. However, even in such a case, when the characteristic curve can be approximated by two curves of quadratic or cubic functions and the upper limit value of the robust region can be specified from the intersection of them, the bearing is considered to have the robust characteristic.

[0110] When the upper limit value of the robust area of the

bearing is in an extremely high load zone, or when the load

capacity of the bearing is extremely small, the oil film

thickness may fall below the allowable oil film thickness

without the upper limit value of the robust region

appearing. In such a case, even if, for the bearing, the

change of minimum oil film thickness with respect to the

crushing load is extremely small in a specific range, it is

not considered to have robust characteristic.

[0111] The magnitude of the crushing load which generates

the robust region and the extent or size of the range of

the robust region generally vary depending on the rigidity

or the balance of the frame, the shaft, the bearing support

portion, and the like. Therefore, the rigidity of each

part is an important parameter in the robust region design

along with the crushing load.

[0112] Further, in addition to the above, the amount of

wear of the upper bearing is also an important parameter in

the robust region design. In a general upper bearing of a

gyration-type crusher of the type in which the main shaft

is supported by the upper bearing 17 and the lower bearing

15, a bearing metal wears over time. Since the contact state of the lower bearing changes to an upper contact tendency as the upper bearing wears, the robust region changes from the initial design or from a new state.

Specifically, for example, when the upper bearing is worn,

the robust region changes to a lower load side compared to

when it was new with no wear. In the examples of FIG. 5

and FIG. 7, when the upper bearing is worn, the respective

characteristic curves move to the left in the page.

[0113] In the gyration-type crusher, in the crushing

chamber 16 formed by the mantle 13 and the conecave 14, if

trying to continue operation in a state where the crushing

process and the discharging process are delayed for some

reason, the raw material staying in the crushing chamber 16

may hinder the rotational movement of the crusher, and an

event may occur in which the load greatly exceeds the

rating instantaneously.

[0114] When such an event occurs, resulting from the torque

characteristic of the motor, a torque exceeding the rated

output of the motor, specifically, for example in a three

phase induction motor, generally the maximum torque of 160%

or more of the rated load state, is generated, and a

bearing load corresponding to the torque may be applied to

the bearing (as a result, a crushing load of 160% or more

is generated). However, from the viewpoint of preventing

mechanical damage to the main body of the gyration-type

crusher, generally some kind of safety device is provided,

and the upper limit value is preferably 200% or less of the rated load of the gyration-type crusher at most. Further, if an excessive crushing load larger than the rated load is generated, an overload acts on the motor. Therefore, the crushing load is more preferably 160% or less.

[0115] When such an event occurs, by setting the robust

region on the load side where the crushing load is larger

than the rated load, reliability can be secured for an

emergency. At this time, an example in which the crushing

load is lower than the normal load (crushing load normally

used depending on the type and properties of raw materials)

or the rated load is lower than the lower limit value of

the robust region can be considered. However, although

when the crushing load is small, the lower contact state

tends to be obtained as described above, since the crushing

load W (bearing load F) is small, a sufficient minimum oil

film thickness Ti is likely to be secured in the first

place as illustrated in FIG. 5 and FIG. 7.

[0116] In contrast, in a plant which crushes relatively

soft raw materials, the gyration-type crusher is often

operated under the condition that the crushing load is

equivalent or less than the rated load, for example, the

crushing load is about 50%. In such operation, the

reliability of the bearing during operation can be improved

by setting the robust region to a region (range) where the

crushing load is low.

[0117] By using a gyration-type crusher using the bearing

15 having the above characteristics, when the crushing load differs due to modifications or changes in the type of the object to be crushed and operating conditions (also including changes in crushing load due to friction of the mantle 13 and the conecave 14), there is no need to confirm the bearing 15 by adjustment/testing again, or select or use an appropriate rotatory crusher, and the operation of the crushing plant can be performed without causing one side contact, whereby improvement in labor, cost, operation rate, and the like can be achieved.

[0118] Note that, since the crushing load is almost

proportional to the motor power, and in actual operation of

the gyration-type crusher, the motor power is easier to

measure and manage directly than the crushing load, it is

more convenient to organize and grasp by the relationship

between the motor power and the minimum oil film thickness

than the relationship between the crushing load and the

minimum oil film thickness. There, in the above result,

the crushing load is normalized with the rated load (rated

value), and therefore the crushing load can be applied to

(replaced with) the motor power as it is.

[0119] Additionally, in FIG. 1 illustrating an example of

the structure of a hydraulic cone crusher which is a

conventional rotatory crusher, the upper bearing 17 is also

provided in the upper portion in addition to the bearing 15

provided in the lower portion. While, the bearing 15

according to this embodiment has the same characteristics

as described above for the gyration-type crusher which does not have the upper bearing 17.

[0120] The gyration-type crusher according to the

embodiment described above can cope with a wide variety of

objects to be crushed robustly and can also cope with the

change of load condition robustly.

[0121] Further, the gyration-type crusher according to the

embodiment described above can avoid the extreme upper

contact state and the extreme lower contact state in the

bearing 15.

[0122] However, a slight upper contact state and a slight

lower contact state are allowed in this technical field,

and rather, it is effective that both the slight upper

contact state and the slight lower contact state occur

during the operation period of the gyration-type crusher

for avoiding the extreme upper contact state and the

extreme lower contact state.

[0123] In that sense, in the bearing 15, when the sliding

mark due to one side contact is generated in both the upper

portion and the lower portion of the inner peripheral

surface, it can be said that an ideal operation state is

secured as in the above-described embodiment.

[0124] In the robust region in the above-described

embodiment, the upper limit value is preferably about 70%

or more, about 80% or more, or about 100% or more of the

rated value of the power of the motor.

[0125] Further, in the robust region in the above-described

embodiment, the upper limit value is preferably about 200% or less, about 160% or less, or about 110% or less of the rated value of the power of the motor.

[0126] Note that the present invention is particularly

effective in a large rotatory crusher. Specifically, it is

particularly effective in a gyration-type crusher having an

inlet dimension of 200 mm or more. Here, the inlet

dimension is the distance between the inner surface of the

conecave 14 and the upper end of the mantle 13 and defines

the maximum dimension of the raw material which can be

supplied to the gyration-type crusher.

[0127] Hereunder, the matters to be considered in the

robust region design of the gyration-type crusher according

to this embodiment will be described.

[0128] As described above, the magnitude of the crushing

load which generates the robust region and the range or

size of the robust region generally change depending on the

rigidity of the frame (casing), the shaft, the bearing

support, and the like, and the balance. Therefore, the

rigidity of each portion is an important parameter in the

robust region design along with the crushing load.

[0129] Specifically, the generation aspect of the one side

state can be adjusted by changing the rigidity of parts

such as the frame 31, the spider 18, the main shaft 5, and

the like which influence the generation aspect of the one

side contact state in the lower bearing 15. At this time,

deformation and displacement of structures such as the main

shaft 5 and the frame 31 are obtained by structural analysis such as FEM (finite element method) and BEM

(boundary element method), and further, using these values,

the oil film thickness of the bearing 15 is obtained by oil

film analysis using the Reynolds equation based on the

fluid lubrication theory (refer to FIG. 5 and the like).

[0130] For example, in a gyration-type crusher where the

lower bearing 15 tends to be in the upper contact state

(upper contact tendency) in a load region where the robust

characteristic is desired, by changing the shapes of the

frame 31, the spider 18, and the main shaft 5 so that the

bending rigidity of the frame 31, the bending rigidity the

torsional rigidity of the spider 18, the bending rigidity

of the main shaft 5 and the like are increased, the

generation aspect of the one side contact state of the

lower bearing 15 in the load region is adjusted from the

upper contact tendency to the lower contact tendency. By

properly designing the lower contact amount, the robust

characteristic in the load region can be obtained.

[0130a] Throughout this specification and the claims which

follow, unless the context requires otherwise, the word

"comprise", and variations such as "comprises" and

"comprising", will be understood to imply the inclusion of

a stated integer or step or group of integers or steps but

not the exclusion of any other integer or step or group of

integers or steps.

[0130b] The reference in this specification to any prior

publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Description of Reference Numerals

[0131]

1 ... upper frame

2 ... lower frame

3 ... main shaft fitting insertion hole

4 ... eccentric sleeve

5 ... main shaft

6 ... thrust bearing

7 ... outer cylinder

9 ... object to be crushed

10 ... main shaft bearing

11 ... eccentric sleeve bearing

12 ... mantle core

13 ... mantle

14 ... conecave

15 ... bearing

16 ... crushing chamber

17 ... upper bearing

18 ... spider

19 ... bevel gear

20 ... driving side bevel gear

21 ... driven side bevel gear

22 ... pulley

23 ... main shaft thrust bearing

24 ... partition plate

25 ... dust seal ring

26 ... dust seal ring cover

27 ... eccentric sleeve fitting insertion hole

31... frame

41 ... shaft

51 ... frame connection portion

Li ... center axis of main shaft 5

L2 ... center axis of upper frame 1

L3 ... center axis of main shaft fitting insertion hole 3

L4 ... center axis of eccentric sleeve 4

L5 ... center axis of eccentric sleeve fitting insertion

hole 27

La ... center axis of shaft 41

Lb ... center axis of inner peripheral surface of bearing 42

o ... intersection of center axis Li of main shaft 5 and

center axis L2 of upper frame 1

F ... crushing load

T ... minimum oil film thickness

Ti ... minimum oil film thickness in lower contact state

T2 ... minimum oil film thickness in even contact state

T3 ... minimum oil film thickness in upper contact state

Claims (20)

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A gyration-type crusher comprising:

a main shaft which is rotatably arranged inside a

conecave and makes an eccentric rotary movement with its

center axis inclined with respect to a center axis of the

conecave;

a mantle provided on the main shaft;

an eccentric sleeve having a main shaft fitting

insertion hole into which a lower end portion of the main

shaft is rotatably inserted;

an outer cylinder having an eccentric sleeve fitting

insertion hole into which the eccentric sleeve is rotatably

inserted,

wherein an outer peripheral surface of the lower end

portion of the main shaft which is inserted into the main

shaft fitting insertion hole and a surface which forms the

main shaft fitting insertion hole form a main shaft bearing

with a lubricating oil supplied between them,

wherein an outer peripheral surface of the eccentric

sleeve which is inserted into the outer cylinder and a

surface which forms the eccentric sleeve fitting insertion

hole form an eccentric sleeve bearing with a lubricating

oil supplied between them, and

wherein at least one of the main shaft bearing and

the eccentric sleeve bearing has a robust region in a

change of a minimum oil film thickness of the lubricating

oil with respect to a change of a motor power which rotationally drives the main shaft.

2. The gyration-type crusher according to claim 1,

wherein a rated value of the motor power exists at or below

an upper limit value of the robust region.

3. The gyration-type crusher according to claim 1 or 2,

wherein a state where a center axis of at least one of the

main shaft bearing and the eccentric sleeve bearing is

substantially parallel to a center axis of a lower portion

of the main shaft exists at or below the upper limit value

of the robust region.

4. The gyration-type crusher according to any one of

claims 1 to 3, wherein the center axis of at least one of

the main shaft bearing and the eccentric sleeve bearing is

substantially parallel to the center axis of a lower

portion of the main shaft at a rated value of the motor

power.

5. The gyration-type crusher according to any one of

claims 1 to 4, wherein in at least one of the main shaft

bearing and the eccentric sleeve bearing, when the motor

power which rotationally drives the main shaft changes from

about 50% to about 160% of its rated value, a position

where an oil film thickness of the lubricating oil is

minimum changes from a bearing lower end side toward a

bearing upper end side.

6. The gyration-type crusher according to claim 5,

wherein in at least one of the main shaft bearing and the

eccentric sleeve bearing, when the motor power which rotationally drives the main shaft changes from about 50% to about 160% of the rated value, the position where the oil film thickness of the lubricating oil is minimum changes from the bearing lower end side to an entire region in a bearing vertical direction.

7. The gyration-type crusher according to any one of

claims 1 to 4, wherein in at least one of the main shaft

bearing and the eccentric sleeve bearing, when the motor

power which rotationally drives the main shaft changes from

about 50% to a maximum allowable value of its rated value,

a position where an oil film thickness of the lubricating

oil is minimum changes from the bearing lower end side to

an entire region in a bearing vertical direction.

8. The gyration-type crusher according to any one of

claims 1 to 4, wherein in at least one of the main shaft

bearing and the eccentric sleeve bearing, when the motor

power which rotationally drives the main shaft changes from

about 50% to a maximum allowable value of its rated value,

a distribution of an oil film pressure of the lubricating

oil changes from a distribution biased toward a bearing

lower portion to a smooth distribution over an entire

region in a bearing vertical direction.

9. The gyration-type crusher according to any one of

claims 1 to 4, wherein in at least one of the main shaft

bearing and the eccentric sleeve bearing, when the motor

power which rotationally drives the main shaft changes from

about 50% to about 160% of its rated value, a distribution of the oil film pressure of the lubricating oil changes from a distribution biased toward a bearing lower portion to a smooth distribution over an entire region in a bearing vertical direction.

10. A gyration-type crusher comprising:

a main shaft which is rotatably arranged inside a

conecave and makes an eccentric rotary movement with its

center axis inclined with respect to a center axis of the

conecave;

a mantle provided on the main shaft;

an eccentric sleeve having a main shaft fitting

insertion hole into which a lower end portion of the main

shaft is rotatably inserted; and

an outer cylinder having an eccentric sleeve fitting

insertion hole into which the eccentric sleeve is rotatably

inserted,

wherein an outer peripheral surface of the lower end

portion of the main shaft which is inserted into the main

shaft fitting insertion hole and a surface which forms the

main shaft fitting insertion hole form a main shaft bearing

with a lubricating oil supplied between them,

wherein an outer peripheral surface of the eccentric

sleeve which is inserted into the outer cylinder and a

surface which forms the eccentric sleeve fitting insertion

hole form an eccentric sleeve bearing with a lubricating

oil supplied between them, and

wherein in at least one of the main shaft bearing and the eccentric sleeve bearing, when a motor power which rotationally drives the main shaft changes from about 50% to about 160% of its rated value, a position where an oil film thickness of the lubricating oil is minimum changes from a bearing lower portion toward a bearing upper portion.

11. A gyration-type crusher comprising:

a main shaft which is rotatably arranged inside a

conecave and makes an eccentric rotary movement with its

center axis inclined with respect to a center axis of the

conecave;

a mantle provided on the main shaft;

an eccentric sleeve having a main shaft fitting

insertion hole into which a lower end portion of the main

shaft is rotatably inserted; and

an outer cylinder having an eccentric sleeve fitting

insertion hole into which the eccentric sleeve is rotatably

inserted,

wherein an outer peripheral surface of the lower

portion of the main shaft which is inserted into the main

shaft fitting insertion hole and a surface which forms the

main shaft fitting insertion hole form a main shaft bearing

with a lubricating oil supplied between them,

wherein an outer peripheral surface of the eccentric

sleeve which is inserted into the outer cylinder and a

surface which forms the eccentric sleeve fitting insertion

hole form an eccentric sleeve bearing with a lubricating

oil supplied between them, and wherein in at least one of the main shaft bearing and the eccentric sleeve bearing, when a motor power which rotationally drives the main shaft changes from about 50% to about 160% of its rated value, a position where an oil film thickness of the lubricating oil is minimum changes from the bearing lower portion to an entire region in a bearing vertical direction.

12. A gyration-type crusher comprising:

a main shaft which is rotatably arranged inside a

conecave and makes an eccentric rotary movement with its

center axis inclined with respect to a center axis of the

conecave;

a mantle provided on the main shaft;

an eccentric sleeve provided to a lower end portion

of the main shaft; and

an outer cylinder having an eccentric sleeve fitting

insertion hole into which the eccentric sleeve is rotatably

inserted,

wherein an outer peripheral surface of the eccentric

sleeve which is inserted into the outer cylinder and a

surface which forms the eccentric sleeve fitting insertion

hole form an eccentric sleeve bearing with a lubricating

oil supplied between them, and

wherein the eccentric sleeve bearing has a robust

region in a change of a minimum oil film thickness of the

lubricating oil with respect to a change of a motor power

which rotationally drives the main shaft.

13. A gyration-type crusher comprising:

a main shaft which is rotatably arranged inside a

conecave and makes an eccentric rotary movement with its

center axis inclined with respect to a center axis of the

conecave;

a mantle provided on the main shaft;

an eccentric sleeve having a main shaft fitting

insertion hole into which a lower end portion of the main

shaft is rotatably inserted; and

an outer cylinder having an eccentric sleeve fitting

insertion hole into which the eccentric sleeve is rotatably

inserted,

wherein an outer peripheral surface of the lower end

portion of the main shaft which is inserted into the main

shaft fitting insertion hole and a surface which forms the

main shaft fitting insertion hole form a main shaft bearing

with a lubricating oil supplied between them,

wherein an outer peripheral surface of the eccentric

sleeve which is inserted into the outer cylinder and a

surface which forms the eccentric sleeve fitting insertion

hole form an eccentric sleeve bearing with a lubricating

oil supplied between them, and

wherein in at least one of the main shaft bearing and

the eccentric sleeve bearing, when a motor power which

rotationally drives the main shaft changes from about 50%

to about 160% of its rated value, a surface pressure

distribution of the lubricating oil changes from a bearing lower portion to a bearing upper portion.

14. A gyration-type crusher comprising:

a main shaft which is rotatably arranged inside a

conecave and makes an eccentric rotary movement with its

center axis inclined with respect to a center axis of the

conecave;

a mantle provided on the main shaft;

an eccentric sleeve having a main shaft fitting

insertion hole into which a lower end portion of the main

shaft is rotatably inserted; and

an outer cylinder having an eccentric sleeve fitting

insertion hole into which the eccentric sleeve is rotatably

inserted,

wherein an outer peripheral surface of the lower

portion of the main shaft which is inserted into the main

shaft fitting insertion hole and a surface which forms the

main shaft fitting insertion hole form a main shaft bearing

with a lubricating oil supplied between them,

wherein an outer peripheral surface of the eccentric

sleeve which is inserted into the outer cylinder and a

surface which forms the eccentric sleeve fitting insertion

hole form an eccentric sleeve bearing with a lubricating

oil supplied between them, and

wherein in at least one of the main shaft bearing and

the eccentric sleeve bearing, when a motor power which

rotationally drives the main shaft changes from about 50%

to about 160% of its rated value, a surface pressure distribution of the lubricating oil changes from a bearing lower portion to an entire region in a bearing vertical direction.

15. The gyration-type crusher according to any one of

claims 1 to 14, further comprising an upper bearing,

wherein an upper end portion of the main shaft is

rotatably supported by the upper bearing.

16. The gyration-type crusher according to claim 15,

wherein the gyration-type crusher is a primary crusher or a

secondary crusher, the secondary crusher being able to be

used as both primary and secondary crushing.

17. The gyration-type crusher according to any one of

claims 1 to 16,

wherein as an operation continues, a unique sliding

mark which cannot be generated in a gyration-type crusher

without the robust region is formed on a bearing.

18. The gyration-type crusher according to claim 17,

wherein the unique sliding mark is formed at least in

a lower portion of the bearing.

19. The gyration-type crusher according to claim 18,

wherein the unique sliding mark is formed only in the

lower portion of the bearing as the operation continues,

and then formed entirely from the lower portion to an upper

portion of the bearing.

20. The gyration-type crusher according to claim 19,

wherein the unique sliding mark is formed only in the

lower portion of the bearing as the operation continues, then formed entirely from the lower portion to the upper portion of the bearing, and then formed only in the upper portion of the bearing.