AU2020410580A1

AU2020410580A1 - Gyratory crusher and method for detecting bearing failure thereof

Info

Publication number: AU2020410580A1
Application number: AU2020410580A
Authority: AU
Inventors: Akimasa Koga
Original assignee: Earthtechnica Co Ltd
Current assignee: Earthtechnica Co Ltd
Priority date: 2019-12-27
Filing date: 2020-12-25
Publication date: 2022-08-18
Anticipated expiration: 2040-12-25
Also published as: ZA202208338B; JP2021107050A; JP7246835B2; WO2021132702A1; AU2020410580B2

Abstract

This rotary crushing machine is provided with a main shaft, and a revolving member. The main shaft is supported in such a way as to be capable of spinning about an axis. The revolving member rotates, causing the axis of the main shaft to revolve. The rotary crushing machine crushes an object to be crushed by means of the movement of the main shaft resulting from the rotation of the revolving member. The rotary crushing machine is provided with a sensor for detecting the rotational speed of the spinning of the main shaft. The possibility of a bearing abnormality is detected on the basis of the rotational speed of spinning of the main shaft when the revolving member is caused to rotate at a prescribed rotational speed in a no-load condition.

Description

DESCRIPTION TITLE OF INVENTION GYRATORY CRUSHER AND METHOD FOR DETECTING BEARING FAILURE THEREOF TECHNICAL FIELD

[0001] The present invention mainly relates to a gyratory crusher.

BACKGROUND ART

[0002] Conventionally, there are known gyratory crushers that crushes rocks and other materials by the action of a concave and a mantle that is attached to a main shaft and rotates eccentrically with respect to the concave. Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2004-519325 discloses this type of gyratory crusher. The gyratory crusher is equipped with a thrust bearing that supports a load acting in the axial direction (a thrust load) and a radial bearing that supports a load acting in the direction perpendicular to the shaft (a radial load).

[0003] Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2004-519325 discloses the method for monitoring the condition of bearings of a crusher. This monitoring method is for monitoring the condition of bearings of a gyratory crusher in order to reduce damage caused by worn bearings. Specifically, the frictional forces between surfaces of the bearings of the crusher are monitored by sensors, and information obtained from the monitoring of the frictional forces performed by the sensors is used for alerting users or controlling the system of the crusher.

CITATION LIST PATENT LITERATURE

[0004] PTL. 1: Japanese Patent Application Publication No. 2004-519325

SUMMARY OF THE INVENTION TECHNICAL PROBLEM

[0005] The configuration of Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2004-519325 is to mount a sensor on a bearing. However, mounting a sensor on a bearing is difficult due to installation space and other factors, and the structure will be too complex in this method. Even if a sensor is mounted to the bearing, the presence of the sensor may have a bad effect on the ease of rotation of the bearing. In this respect, there was room for improvement.

[0006] The present invention was made in view of the above circumstances, and its purpose is to make it possible to detect possibilities of failures of a radial bearing and a thrust bearing of a gyratory crusher with a simple configuration.

[0007] Problems to be solved by this present invention are as described above. Solutions to the problems and advantageous effects thereof are to be described below.

[0008] A first aspect of the present invention provides a gyratory crusher configured as follows. That is, the gyratory crusher is equipped with a main shaft and a swivel member. The main shaft is supported to be rotatable around an axis. The swivel member swivels the axis of the main shaft by rotating. The gyratory crusher crushes the object to be crushed by workings of the main shaft moved by a rotation of the swivel member. The gyratory crusher is equipped with a sensor to detect a rotation speed of the main shaft. The possibility of a failure of bearings will be detected based on the rotation speed of the main shaft with the swivel member rotating at a predetermined rotation speed under a no-load condition.

[0009] This makes it possible to easily assess a possibility of a failure of bearings with a frequency of the axial rotations of the main shaft that occurs as its axis rotates.

[0010] A second aspect of the present invention provides a method for detecting a failure of bearings of a gyratory crusher described as follows. That is, the gyratory crusher is equipped with a main shaft and a swivel member. The main shaft is supported to be rotatable around an axis. The swivel member swivels the axis of the main shaft by rotating. The gyratory crusher crushes the object to be crushed by the working of the main shaft moved by a rotation of the swivel member. In the above-mentioned bearing failure detection method, a possibility of failure of bearings that supports the main shaft in the gyratory crusher is detected. In the baring failure detection method, a sensor detects the rotation speed of the main shaft with the swivel member rotating at a predetermined rotation speed under a no-load condition.

[0011] This makes it possible to easily assess a possibility of a failure of bearings with the frequency of the axial rotations of the main shaft that occurs as its axis rotates.

ADVANTAGEOUS EFFECTS OF THE INVENTION

[0012] The present invention enables the detection of possibilities of failures in a radial bearing and a thrust bearing of a gyratory crusher with a simple configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] [FIG. 1] A side cross-sectional view showing an overall configuration of a gyratory crusher of one embodiment of the present invention.

[FIG. 2] A side cross-sectional view showing a mounting configuration of a rotary encoder above a main shaft.

[FIG. 3] A side cross-sectional view showing an existing gyratory crusher.

DESCRIPTION OF EMBODIMENTS

[0014] Embodiments of the present invention and modifications thereof will be described below with reference to the drawings. FIG. 1 is a schematic side cross-sectional view of a gyratory crusher 100 of one embodiment of the present invention. In FIG. 1, some structures such as the support structure of an upper end of a main shaft 4 are shown in simplified form.

[0015] The gyratory crusher 100 of the embodiment shown in FIG. 1 crushes rocks and other materials to an appropriate grain size. The gyratory crusher 100 has an upper frame 11, a lower frame 13, a spider 14, a main shaft 4, a mantle 5, a concave 6, an eccentric sleeve (swivel member) 7, and a power transmission mechanism 20.

[0016] The upper frame 11 and lower frame 13 are both hollow in shape. The upper frame 11 and lower frame 13 are fixed to each other in the vertical direction. Thus, the cylindrical outer structure is constructed and the main shaft 4 is accommodated in it. The main shaft 4 is able to precess around its upper end.

[0017] The mantle 5 attached to the main shaft 4 and the concave 6 attached to the inner surface of the upper frame 11 constitute a crushing chamber S. As described in detail below, the space between the mantle 5 and the concave 6 increases and decreases with the precession of the main shaft 4. As a result, a compressive force will be exerted on rocks inside the crushing chamber S to crush them.

[0018] The upper frame 11 forms the upper outline of the gyratory crusher 100. An upper end of the upper frame 11 is connected to the lower end of the outer edge of the spider 14. The lower end of the upper frame 11 is connected to the upper end of the lower frame 13. The concave 6 is installed on the inner surface of the upper frame 11.

[0019] The lower frame 13 forms the lower outline of the gyratory crusher 100. The upper end of the lower frame 13 is connected to the lower end of the upper frame 11. In this embodiment, the lower frame 13 is shaped to increase in diameter downwardly. The lower end of the lower frame 13 is open, and the crushed rocks can be collected from this opening.

[0020] The main shaft 4 is configured as a long shaft-like member. The main shaft 4 is accommodated inside the spider 14, the upper frame 11 and the lower frame 13. The main shaft 4 is accommodated in order to be at the center inside these frames, both in planar view and in side view, with its axis generally heading in vertical direction. The upper end of the main shaft 4 is supported on the outer edge of the spider 14 by a spider arm 31. More precisely, the upper end of the main shaft 4 is supported by an upper bearing 50 which is installed at the center of the spider 14 (described below as a spider central section 30). This configuration allows the main shaft 4 to rotate and also to change the direction of its axis (axis of rotation) with its upper end being as a fulcrum.

[0021] The middle part of the main shaft 4 is conical in shape with its diameter increases downwardly. The distance between the outer surface of this conical portion and the inner surface of the upper frame 11 gradually be shortened, downwardly, from the upper end to the lower end of the conical portion.

[0022] The spider 14 supports the upper end of the main shaft 4 among the upper frame 11. The spider 14 consists of a spider central section 30 and a plurality of spider arms 31 (in this embodiment, there are two of them). The spider central section 30 is located in the center of the spider 14 in planar view. The spider arms 31 are configured in the form of arms. Each spider arm 31 connects the spider central portion 30 and the outer edge of the spider 14.

[0023] The mantle 5 is configured as a member that is hollow and generally conical. The mantle 5 is attached to the outer surface of the conical shaped portion of the main shaft 4 described above.

[0024] The concave 6 is configured by a plurality of generally plate-shaped members installed onto the inner surface of the upper frame 11 next to each other. As shown in FIG. 1, the distance between the tip (tooth tip) of the concave 6 and the tip (tooth tip) of the mantle 5 gradually be shorten downwardly. The concave 6 may be configured as a single hollow member instead of as an assemblage of multiple members.

[0025] The mantle 5 and the concave 6 are formed of hard, abrasion-resistant material such as high manganese steel for they are the parts that act on rocks to be crushed. The mantle 5 and the concave 6 are also formed as removable so that they can be replaced when worn to a certain degree.

[0026] The lower part of the main shaft 4 is inserted into an eccentric sleeve 7 and supported by a lower bearing 8. The lower bearing 8 consists of a thrust bearing 8a and a radial bearing 8b. The thrust bearing 8a supports the lower end of the main shaft 4. The thrust bearing 8a is supported by a piston 10 of a main shaft lifting hydraulic cylinder 9 which is installed at the lower end of a boss section 13a of the lower frame 13. The radial bearing 8b is configured as a cylindrical bush installed between the main shaft 4 and the eccentric sleeve 7.

[0027] The eccentric sleeve 7 is rotationally driven by the power transmission mechanism 20 described below, with the lower end of the main shaft 4 inserted in a through hole portion thereof. The said through hole of the eccentric sleeve 7 is circularly configured and eccentrically positioned with respect to the axis of rotation of the eccentric sleeve 7. A bush, not shown in the drawings, is installed between the main shaft 4 and the inner surface of the through hole of the eccentric sleeve 7. With this bush, the main shaft 4 is inserted into the eccentric sleeve 7 in a state that it can rotate relatively with respect to the said through hole.

[0028] The power transmission mechanism 20 transmits power for rotating the eccentric sleeve 7 to the eccentric sleeve 7. The power transmission mechanism 20 has a transverse shaft 21, a bevel pinion 22, and a bevel gear 23.

[0029] The transverse shaft 21 is a shaft-shaped member. With its axis of rotation heading in a horizontal (transverse) direction, the transverse shaft 21 is supported into the lower frame 13 by the bearing 15. A bevel pinion 22 is fixed to one of the ends of the transverse shaft 21 which is closer to the main shaft 4. The transverse shaft 21 rotates when power is transmitted from a drive source (e.g., an electric motor) via such as a V-belt and a V-pulley, which leads to the bevel pinions 22 also rotating.

[0030] The bevel gear 23 is fixed to the lower end of the eccentric sleeve 7. The bevel gear 23 meshes with the bevel pinion 22. As a result, the power transmitted to the transverse shaft 21 will be transmitted to the bevel gear 23, leading to the eccentric sleeve 7 rotating.

[0031] As described above, the power from the drive source is transmitted to the transverse shaft 21 and further to the eccentric sleeve 7 via the bevel pinion 22 and the bevel gear 23. As a result, the lower end of the main shaft 4 inserted into the said through hole of the eccentric sleeve 7 rotates in the virtual horizontal plane. That is, the main shaft 4 swivels its lower end around the portion supported by the upper bearing 50, which is a radial bearing, while sequentially changing the direction of its axis of rotation, thereby performs a so-called precession.

[0032] The precession of the main shaft 4 makes the position of the mantle 5 in planer view change periodically, so that the distance between the lower edge of the concave 6 and the lower edge of the mantle 5 repeatedly increases and decreases.

[0033] The rocks are crushed in the crushing chamber S which is the space inside the upper frame 11 where the mantle 5 and the concave 6 are accommodated. That is, the rocks fed from above the upper frame 11 are crushed by workings of the mantle 5 and the concave 6.

[0034] The gap between the mantle 5 and the concave 6 gradually increases as the rocks and other materials have been crushed there over a long period of time and they get worn. In this regard, the gyratory crusher 100 can raise the main shaft 4 by driving the main shaft lifting hydraulic cylinder 9. As a result, the proper size of the gap can be maintained even when the mantle 5 and the concave 6 are worn out.

[0035] Next, the spider central section 30 and a rotary encoder attached thereto will be described in detail below. FIG. 2 is a side cross-sectional view showing the mounting configuration of the rotary encoder 33 above the main shaft 4.

[0036] The spider central section 30 is a generally short cylindrical member with its axis heading in a vertical direction. In the center of the spider central section 30 in planar view, an axial hole in the vertical direction is formed in a through shape (this through hole may hereinafter be referred to as the central through hole). In other words, the said central through hole is formed in a generally cylindrical shape in the center of the spider central section 30.

[0037] At the lower part of the central through hole, the spider central section 30 has a circular flange portion 30a in planar view protruding inwardly in the inner radial direction. (As a result, the bottom of the central through hole is formed a stepped shape.) Outside of the flange portion 30a, a cylinder wall portion 30b is formed around the entire circumference. The cylinder wall portion 30b extends upwardly from the periphery of the flange portion 30a.

[0038] Above the flange portion 30a of the spider central section 30, a bearing mount portion 12 is installed.

[0039] The upper bearing 50 is installed being mounted on top of the bearing mount portion 12 of the spider central section 30. The upper bearing 50 is a known spherical bearing composed chiefly of an outer ring 51 and an inner ring 52.

[0040] A shaft hole is formed in the inner ring 52 of the upper bearing 50 (spherical bearing). The upper end of the main shaft 4 is inserted into this shaft hole, so that the upper end of the main shaft 4 is supported by the upper bearing 50.

[0041] As a result, the upper end of the main shaft 4 is able to rotate in the circumferential direction relatively with respect to the inner ring 52 and to move in the direction along the axis of the shaft hole of the inner ring 52. Since the inner ring 52 is able to rotate about any axis relative to the outer ring 51, the upper end of the main shaft 4 inserted into the shaft hole of the inner ring 52 can change the direction of its axis of rotation.

[0042] The upper bearing 50 (spherical bearing) is assembled inside the spider central section 30 being mounted on top of the bearing mount portion 12.

[0043] A fixing member (a first hollow member) 71 is provided at the top of the spider central section 30. This fixing member 71 can fix the upper bearing 50 (spherical bearing) to the spider central section 30 by holding down the outer ring 51 from an upper side.

[0044] The fixing member 71 has a cylindrical portion 71a and two flange portions 71b, 71c. An interior space of the cylindrical portion 71a can accommodate the upper end of the main shaft 4. One flange portion 71b extends radially outward from the upper end of the cylindrical portion 71a. Another flange portion 71c extends radially outward from the lower end of the cylindrical portion 71a.

[0045] In this configuration, the fixing member 71 is attached to the spider central section 30 from an upper side, with the upper bearing 50 mounted on top of the bearing mount portion 12 that belongs to the spider central section 30. When the fixing member 71 is installed, the lower end of the cylindrical portion 71a is inserted into the said central through hole of the spider central section 30 and gets in contact with the outer ring 51 of the upper bearing 50. This allows the upper bearing 50 to be fixed in order not to move in the vertical direction. To attach the fixing member 71 to the spider central section 30, bearing fixing bolts 72 are used.

[0046] In this embodiment, an extension cylinder (an extension member, a second hollow member) 32 is provided on top of the fixing member 71. Like the fixing member 71, the extension cylinder 32 has a cylindrical portion. The extension cylinder 32 isfixed to an upper side of the fixing member 71 so that an interior space of the fixing member 71 is connected to an interior space of the extension cylinder 32. In other words, the interior space of the fixing member 71 is extended substantially upward. Inside the extension cylinder 32, the rotary encoder 33 is provided as a sensor to detect the rotation speed of the main shaft 4.

[0047] The extension cylinder 32 is provided for the purpose of creating a space in the upper part of the fixing member 71 to accommodate the rotary encoder 33. The upper part of the extension cylinder 32 is covered by a lid member 34. In FIG. 2, it is shown that this lid member 34 is attached to the extension tube 32, however, it may also be attached directly to the fixing member. In addition, the gyratory crusher 100 in this embodiment is a modification of an existing gyratory crusher (shown in FIG.3) which does not have the extension cylinder 32 and the lid member 34 thereof is directly attached to the fixing member 71 in its configuration. Thus, the extension cylinder 32 substantively functions as a vertical spacer.

[0048] In this embodiment, simply by attaching the extension cylinder 32 between the fixing member 71 and the lid member 34, a space to accommodate the rotary encoder 33 and a flexible shaft 35 can be formed above the main shaft 4. Therefore, it is easy to apply this configuration to an existing gyratory crusher 100.

[0049] The extension cylinder 32 is fixed to the fixing member 71 using fixing bolts 38. The lid member 34 is fixed to the extension cylinder 32 using fixing bolts 41. In this embodiment, the fixing member 71, the extension cylinder 32 and the lid member 34 belong to the spider 14.

[0050] The rotary encoder 33 can detect the rotation of a detecting shaft which is not shown in drawings. The rotary encoder 33 is attached to the inner wall of the extension cylinder 32. For example, a known configuration in which an optical sensor or any other device detects the rotation of a disc may be adopted as the rotary encoder 33.

[0051] The detecting shaft of the rotary encoder 33 is provided to be generally vertical to the axis of the main shaft 4. This detecting shaft is connected to the top of the main shaft 4 via a flexible shaft 35. The flexible shaft 35 is a member that transmits rotational power to a remote position. Couplings 36a and 36b are provided at both ends of the flexible shaft as connecting members.

[0052] The coupling 36a provided at one end of the flexible shaft 35 is connected to the main shaft 4. The coupling 36b provided at the other end of the flexible shaft 35 is connected to the detecting shaft of the rotary encoder 33. The rotation of the main shaft 4 is transmitted to the rotary shaft of the rotary encoder 33 via the flexible shaft 35, and the rotary encoder 33 detects the rotation speed of the main shaft 4. The rotation detecting signal generated by the rotary encoder 33 is output via a signal line (wire) which is not shown in drawings. This signal line may be configured to be fixed to the spider arm 31, for example.

[0053] Pulling the signal line connected to the rotary encoder 33 out of the gyratory crusher 100 allows the operator or other person to monitor failures of bearings without coming close to the gyratory crusher 100. Thus, the cost of monitoring can be significantly reduced.

[0054] The power transmission mechanism 20 described above rotates the eccentric sleeve 7, and the main shaft 4 is able to rotate relatively with respect to the eccentric sleeve 7. In other words, in the gyratory crusher 100, power is used to swivel the axis of the main shaft 4, but not to rotate the main shaft 4 about its axis. In the following description, the rotation of the axis of the main shaft 4 may be referred to as "orbital rotation", and the rotation of the main shaft 4 about its axis may be referred to as "axial rotation".

[0055] In the configuration of the present embodiment, it is not possible to acquire the frequency of axial rotations of the main shaft 4 by using a rotation sensor provided with respect to an appropriate transmission shaft of the power transmission mechanism 20. However, as in the present embodiment, using the rotary encoder 33 and the flexible shaft provides a simple mechanism enables the detection of the frequency of axial rotations of the main shaft 4.

[0056] The frequency of the axial rotations of the main shaft 4 with the eccentric sleeve 7 rotating at a predetermined rotation speed is a good indicator here, to determine whether the lower bearing 8 (specifically, any of the thrust bearing 8a and the radial bearing 8b) has been damaged or has other failures.

[0057] That is, when both of the trust bearing 8a and the radial bearing 8b are functioning properly, the relative rotation of the members allowed by the lower bearing 8 is smooth. Therefore, when the eccentric sleeve 7 rotates (when the main shaft 4 orbitally rotates), the main shaft 4 will axially rotates slightly due to the viscosity of the lubricating oil or some other materials like that, but the frequency of the axial rotations will not be very high. On the other hand, if at least one of the trust bearing 8a and the radial bearing 8b is damaged for some reason, the relative rotation of the members provided by the lower bearing 8 would not be so smooth. Therefore, as the main shaft 4 rotates orbitally, a large force that makes the main shaft 4 axially rotate will be generated.

[0058] Therefore, in this embodiment, the eccentric sleeve 7 is driven at a predetermined rotation speed (criterial rotation speed) with no rock or other material fed into the crushing chamber S (that is to say, a no-load condition), and then the axial rotation speed of the main shaft 4 is measured. As the result of this measurement, if the axial rotation speed of the main shaft 4 turns out to increase by a predetermined degree compared to before, it can be estimated that the lower bearing 8 has been damaged.

[0059] For example, given that the gyratory crusher 100 is driven so as to have a rate of 360 orbital rotations per minute under a no-load condition in the first operation of the gyratory crusher 100 after its installation, and the main shaft 4 turns out to axially rotate 20 times per minute as the result of the measurement. It is preferable to store this initial axial rotation speed in the computer's memory for automatic checking. After this initial measurement, the gyratory crusher 100 is put into operation. Thereafter, the axial rotation frequency is periodically or irregularly checked, with the same rotation speed of gyratory crusher 100 as described above under a no-load condition. A system can be configured to prompt the operator to inspect the lower bearing 8 if the frequency of axial rotations becomes, for example, over three times higher than the initial frequency, namely, more than rotations per minute.

[0060] The check of the axial rotation speed can be configured, for example, to be performed at the direction of the operator during periodic maintenance with confirmation that the crusher is under a no-load condition. Note, however, that whether or not the gyratory crusher is under a no-load condition cat be automatically determined by a hydraulic pressure sensor that detects the hydraulic pressure of the lower cylinder 9. It is also possible to automatically determine whether or not the gyratory crusher 100 is under a no-load condition by a sensor installed on the feed conveyor that feeds rocks and other materials into the gyratory crusher 100. Therefore, the check of the axial rotation speed described above can be configured to be performed automatically when a no-load condition is detected during the process of operation of the gyratory crusher 100.

[0061] If the rotation speed increases significantly and the bearings are suspected to have been damaged, the operator can be alerted by working of an alerting member (e.g., lighting of a lamp). This allows for an early handling. In addition, the gyratory crusher 100 may be automatically controlled to be substantially limited in the operation. Methods for controlling the limit operation include, but are not limited to, reducing the amount of rocks loaded into the crusher by decreasing the speed of feed conveyor and widening the space of the crushing chamber S by lowering the main shaft 4 by the piston 10. Lightening the load on the bearings through the limited operation enables the prevention of a serious failure that could lead to a prolonged shutdown of the operation.

[0062] The configuration in which the axial rotation of the main shaft 4 itself is detected, as the present embodiment, is advantageous in terms of the fact that it makes it easier to detect failures than the conventional configuration in which the frictional force between the surfaces of bearings is detected. The detection structure of the present embodiment is also superior in terms of the fact that it does not affect the ease of rotation of the main shaft 4, since a top surface 4a of the main shaft 4 is not supported by a bearing.

[0063] As described above, the vertical position of the main shaft 4 is changed by the operation of the main shaft lifting hydraulic cylinder 9. In the present embodiment, however, the top surface 4a of the main shaft 4 and the rotary encoder 33 are connected by the flexible shaft 35. Therefore, even if the positional relationship between the rotary encoder 33 and the main shaft 4 changes, the axial rotation of the main shaft can be steadily detected.

[0064] As described above, the gyratory crusher 100 of the present embodiment has the main shaft 4 and the eccentric sleeve 7. The main shaft 4 is supported to be rotatable around its axis. The eccentric sleeve 7 rotates to swivel the axis of the main shaft 4. The gyratory crusher 100 crushes the object to be crushed by workings of the main shaft 4 moved by the rotation of the eccentric sleeve 7. The gyratory crusher 100 is equipped with the rotary encoder 33 that detects the axial rotation speed of the main shaft 4. Possibilities of failures of the bearings (especially, that of the bearing 8) is detected based on the axial rotation speed of the main shaft 4 when the eccentric sleeve 7 is rotating at a predetermined rotation speed under a no-load condition.

[0065] This makes it possible to easily assess a possibility of a failure of bearings (especially, hat of the lower bearing 8) with the frequency of the axial rotations of the main shaft 4 that occurs as its axis rotates.

[0066] Within the gyratory crusher 100 of the present embodiment, the rotary encoder 33 detects the frequency of the axial rotations of the main shaft 4 by detecting the rotations of the top surface 4a of the main shaft 4.

[0067] This makes it possible to detect a possibility of a failure of the bearings not affecting the operation of the bearing 50 supporting the main shaft 4.

[0068] The gyratory crusher 100 of the present embodiment is also equipped with the flexible shaft 35. The speed of axial rotation of the main shaft 4 is detected by the rotary encoder 33. The flexible shaft 35 connects the top surface 4a of the main shaft 4 and the detecting shaft of the rotary encoder 33.

[0069] This makes it possible to assess the frequency of the axial rotations of the main shaft 4 with a simple and inexpensive configuration.

[0070] The gyratory crusher 100 of the present embodiment is also equipped with the fixing member 71 and the extension cylinder 32. The fixing member 71 can accommodate the upper end of the main shaft 4 inside. The extension cylinder 32 is fixed to the upper side of the fixing member 71. The interior space of the fixing member 71 is connected to the interior space of the extension cylinder 32.

[0071] By additionally installing the extension cylinder 32 to the existing gyratory crusher, a space to install the rotary encoder 33 and other members easily formed above the main shaft 4.

[0072] Within the gyratory crusher 100 of the present embodiment, the rotary encoder 33 is installed inside the extension cylinder 32.

[0073] In this manner, the space for the rotary encoder 33 is provided.

[0074] The gyratory crusher 100 is also equipped with the spider 14 that supports the upper end of the main shaft 4 keeps it rotatable. The rotary encoder 33 is installed on the spider 14.

[0075] Therefore, electrical signals output by the rotary encoder 33 can be transmitted through wires installed to the spider arms 31 to the outside of the gyratory crusher 100. In this manner, an electrical signal path for remote detection of failures can be easily formed.

[0076] In addition, in the gyratory crusher 100 of the present embodiment, a possibility of a failure of the bearings will be detected by the rotary encoder 33 detecting the frequency of the axial rotations of the main shaft 4 when the eccentric sleeve 7 is rotating at a predetermined rotation speed under a no-load condition.

[0077] In this manner, it is possible to easily assess a possibility of a failure of the bearings (especially, that of the lower bearing 8) by using the frequency of the axial rotations of the main shaft 4 that occurs as its axis rotates.

[0078] Also, in the gyratory crusher 100 of the present embodiment, the frequency of the axial rotations of the main shaft 4 with the eccentric sleeve 7 rotating at a predetermined criterial rotation speed under a no-load condition (that is to say, the measured axial rotation frequency) is obtained by the rotary encoder 3. In this gyratory crusher 100, furthermore, the frequency of the axial rotations of the main shaft 4 with the eccentric sleeve 7 rotating at the said criterial rotation speed under a no-load condition and also under a proper condition is obtained by the rotary encoder 33 in addition. Then, based on the rotation speed obtained, the threshold rotation frequency (e.g., three times higher than the frequency of the axial rotations obtained) is determined. If the measured axial rotation frequency is higher than the threshold rotation frequency, a possibility of a failure of the lower bearing 8 is determined.

[0079] In this manner, a possibility of a failure of the bearings (especially, the lower bearing 8) is determined with a clear criterion.

[0080] Although the preferred embodiments of the present invention has been described above, the configurations described above may be modified as follows, for example.

[0081] The rotation speed of the eccentric sleeve 7 (that is to say, the criterial rotation speed) in checking the axial rotation speed may be equal to or different from its rotation speed during normal operation.

[0082] As a configuration for detecting the rotation of the top surface 4a of the main shaft4, various sensors such as a camera, an optical sensor, and a magnetic sensor may be adopted instead of the rotary encoder 33. When a camera is adopted, a possible configuration is to detect the rotation of a mark put on the top surface 4a of the main shaft 4 by image processing. Since the detection of the rotation by an optical sensor and a magnetic sensor can be achieved by known configurations, the description thereof are omitted here. In cases of adopting a camera, an optical sensor, or a magnetic sensor, the rotation can be flexibly detected even if main shaft 4 moves in the vertical direction because the rotation is detected in a non-contact manner.

[0083] The axial rotation of the main shaft 4 may be detected by optical sensors or magnetic sensors placed facing to the outer surface of the main shaft 4 and detecting the rotation of the outer surface of the main shaft 4.

[0084] Instead of by attaching the extension cylinder 32 to the fixing member 71, a space above the main shaft 4 for the rotary encoder 33 and the flexible shaft 35 may be provided by removing the fixing member 71 and replacing it with another longer fixing member. In this case, it goes without saying that the rotary encoder 33 is installed to the said fixing member adopted instead of the fixing member 71 and the extension cylinder 32.

[0085] Instead of fixed to the inner wall of the extension cylinder 32, the rotary encoder 33 may be fixed to, for example, the bottom surface of the lid member 34.

[0086] The configuration of the gyratory crusher 100 is not limited to that in which the main shaft 4 is raised and lowered by the main shaft lifting hydraulic cylinder 9 to adjust the space between the mantle 5 and the concave 6, it may be changed to a known mechanical configuration, etc. In one example of a mechanical configuration, a concave is supported via a screw mechanism and installed inside the upper frame. The space between a mantle and the concave can be adjusted by raising and lowering the concave with the screw mechanism.

DESCRIPTION OF THE REFERENCE NUMERALS

[0087] 4 main shaft 7 eccentric sleeve (swivel member) 11 frame 14 spider 15 bearing 33 rotary encoder (sensor) 35 flexible shaft 100 gyratory crusher S crushing chamber

Claims

1. A gyratory crusher, comprising:

a main shaft supported to be rotatable around its axis; and

a swivel member that rotates to swivel the axis of the main shaft,

wherein the gyratory crusher crushes objects to be crushed by workings of the

main shaft moved by a rotation of the swivel member,

the gyratory crusher is equipped with a sensor to detect a frequency of axial

rotations of the main shaft, and

a possibility of a failure of bearings is detected based on a frequency of axial

rotations of the main shaft with the swivel member rotating at a predetermined rotation

speed.

2. The gyratory crusher according to claim 1, wherein

the sensor detects a frequency of axial rotations of the main shaft by detecting

rotations of a top surface of the main shaft.

3. The gyratory crusher according to claim 2, wherein

the gyratory crusher comprises a flexible shaft,

the sensor is a rotary encoder, and

the flexible shaft connects the top surface of the main shaft and a detecting shaft of the

rotary encoder.

4. The gyratory crusher according to any one of claims 1 to 3, wherein

the gyratory crusher comprises a first hollow member capable of accommodating

an upper end of the main shaft inside, and the sensor is installed on the first hollow member.

5. The gyratory crusher according to any one of claims 1 to 3, wherein

the gyratory crusher comprises;

a first hollow member capable of accommodating an upper end of the main

shaft inside, and

a second hollow member fixed to an upper side of the first hollow member,

and

an interior space of the first hollow member is connected to an interior space of

the second hollow member.

6. The gyratory crusher according to claim 5, wherein

the sensor is installed on the second hollow member.

7. The gyratory crusher according to any one of claims 1 to 6, wherein

the gyratory crusher comprises a spider supporting the upper end of the main shaft

to be rotatable, and

the sensor is installed to the spider.

8. A method for detecting a bearing failure with regard to a gyratory crusher

comprising:

a main shaft supported to be rotatable around its axis; and

a swivel member that rotates to swivel the axis of the main shaft,

wherein the gyratory crusher crushes objects to be crushed by workings of

the main shaft moved by a rotation of the swivel member, wherein the method is for detecting a possibility of a failure of bearings supporting the main shaft, and a sensor detects a frequency of axial rotations of the main shaft with the swivel member rotating at a predetermined rotation speed under a no-load condition.

9. The method for detecting a bearing failure with regard to the gyratory crusher

according to claim 8, wherein

the possibility of a failure of the bearings is determined when a frequency of axial

rotations of the main shaft obtained by the sensor with the swivel member rotating at a

predetermined criterial rotation speed under a no-load condition is higher than a threshold

rotation frequency determined based on a frequency of axial rotations of the main shaft

obtained by the sensor in advance with the swivel member rotating at the criterial rotation

speed under a no-load and proper condition.