AU2018325823A1

AU2018325823A1 - Gyratory crusher

Info

Publication number: AU2018325823A1
Application number: AU2018325823A
Authority: AU
Inventors: Takashi Kijima; Akimasa Koga; Atsushi Oyama; Yoshichika Sato; Takakazu SHIRACHI
Original assignee: Earthtechnica Co Ltd
Current assignee: Earthtechnica Co Ltd
Priority date: 2017-08-31
Filing date: 2018-08-31
Publication date: 2020-04-23
Anticipated expiration: 2038-08-31
Also published as: AU2018325823B2; JPWO2019045042A1; WO2019045042A1; JP7145864B2

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

GYRATION-TYPE CRUSHER

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 Art [0002] Conventionally, a gyration-type crusher such as a gyratory crusher or a cone crusher has been used as a crusher for crushing large raw stones (rocks) . Of conventional 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 conventional gyration-type crusher illustrated in FIG. 1, a main shaft 5 whose center axis Ll 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 Ll 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 Pl 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 Pl 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 Pl 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 Pl 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 Pl 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 is generally known. However, there was a problem that it requires excessive cost, labor, and time for processing and the like.

Related Art Document

Patent Document [0021] Patent Document 1: Japanese Patent Application Laid-open No. 2011-11187 A

Summary of the Invention

Problem to be solved by the Invention [0022] The present invention was made for solving the above-mentioned problem of the related art, and its object is to 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.

Means for solving the problem [0023] In order to solve the above-mentioned problem, 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] In order to solve the above-mentioned problem, 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] In order to solve the above-mentioned problem, 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] In order to solve the above-mentioned problem, 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] In order to solve the above-mentioned problem, 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] In order to solve the above-mentioned problem, 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] An 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.

Advantageous Effect of the Invention [0043] According to 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]

FIG. 1 is a longitudinal section view illustrating the whole structure of one example of a conventional 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 Ll 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 .

Embodiment of the Invention [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 Tl, T2, and T3, respectively.

[0054] Here, the main shaft bearing 10 and the eccentric sleeve bearing 11 will be individually described as follows.

[0055] 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 with respect to Lb	<0	%0	>0
Contact state	lower	substantially	upper
	contact	even	contact

Minimum oil film thickness T

large

medium

small

[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= ( ηn/P) (r/c)² [0064] Here, η is viscosity coefficient of lubricating oil [P=10^_1Pa ·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) .

[0066] 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 gyrationtype 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 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. 10 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 T1 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 threephase 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 T1 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.

Description of Reference Numerals [0131]

... upper frame

... lower frame

... main shaft fitting insertion hole

... eccentric sleeve

... main shaft

... thrust bearing

... outer cylinder

... object to be crushed

... mam shaft bearing

... eccentric sleeve bearing

... mantle core

... mantle

... conecave

... bearing

... crushing chamber

... upper bearing

... spider

... bevel gear

... driving side bevel gear

... driven side bevel gear

... pulley

... main shaft thrust bearing

... partition plate

... dust seal ring

... dust seal ring cover

... eccentric sleeve fitting insertion hole

... frame

... shaft

... frame connection portion

center axis	of main shaft 5
center axis	of upper frame 1
center axis	of main shaft fitting insertion hole 3
center axis	of eccentric sleeve 4 57

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

... 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

T1 ..	. 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

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 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 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 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 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 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.