GB2074666A

GB2074666A - Speed Change Gearing for Crusher

Info

Publication number: GB2074666A
Application number: GB8113009A
Authority: GB
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 1980-04-30
Filing date: 1981-04-28
Publication date: 1981-11-04
Also published as: AU6985381A; ZA812722B; AU532909B2; JPS56153121A; IN154208B; GB2074666B

Abstract

A speed change gearing 5 of a crusher for crushing coal or other solid material connected to the lower end of a main body of the crusher for transmitting drive force from a motor to the main body of the crusher includes a thrust bearing 11 for bearing all the load applied to the gearing by rotary members of the crusher and the solid material in the main body of the crusher. To avoid wear, a race, 11a, 11b of the thrust bearing 11 or a part 6, 9, 10 positioned against such race is subjected to surface treatment, to increase the wear resistance of its surface. <IMAGE>

Description

SPECIFICATION Speed Change Gearing for Crusher Background of the Invention (1) Field of the Invention This invention relates to speed change gearings, and more particularly it is concerned with a speed change gearing for a vertical type crusher located on the gearing for crushing solid material, such as coal, for transmitting power from a driving machine to a rotating element of the crusher.

(2) Description of the Prior Art This type of speed change gearing has located thereon a crusher for crushing coal or the solid material with rotating balls and all the load applied by the rotary members of the crusher, the force applying member and the solid material is supported by a thrust bearing mounted in the speed change gearing.

During operation for crushing the solid material, this type of speed change gearing must support a varying thrust load on the order of several hundred tons applied thereto, and this varying thrust load is accommodated through the thrust bearing by a gear casing positioned against the thrust bearings. Under these severe operating conditions, the gear casing develops on its surface phenomena of wear including fretting, exfoliation, etc, More specifically, when a large varying load is applied to the thrust bearing, the thrust bearing and the gear casing in contact with the thrust bearing move relative to each other, thereby causing a change to occur in the pressure applied to the interface. This would result in the aforesaid phenomena of wear occurring on the interface, particularly on the surface of the gear casing.With the phenomena of wear further developing, the material of the gear casing would have its fatigue strength reduced and develop cracks, thereby resulting in breaking of the gear casing. Thus there would be the risk that the service life of the gearing is shortened. When grits produced by wear are incorporated in the lubricant, the thrust bearing would be adversely affected. Also, the grits in the lubricant might undergo oxidation and render the lubricant opaque and give rise to the problem that the oil gauge for checking on the volume of the lubricant might be rendered inoperative.

Summary of the Invention A principle object of this invention is to provide a speed change gearing for a crusher capable of avoiding wear that might otherwise be caused on a race of a thrust bearing or a member positioned against the race, to thereby prolong the service life of the gearing.

Another object is to provide a speed change gearing for a crusher which is provided with means for positively supplying lubricant to a surfaces on which wear might be caused, to thereby avoid the phenomena of wear occurring in the gearing.

Still another object is to provide a speed change gearing for a crusher which facilitates replacing of its parts in maintenance.

The outstanding characteristic of the invention that enables the aforesaid objects to be accomplished is that surface treatment is given to a race of a thrust bearing or a member positioned against the race to improve the wear resistance property of the material.

Brief Description of the Drawings Fig. 1 is a schematic view in explanation of the construction of a crusher including a speed change gearing; Fig. 2 is a schematic vertical sectional view of a speed change gearing for a crusher; Fig. 3 is a schematic vertical sectional view of the speed change gearing comprising a first embodiment of the invention, showing its essential portions; Fig. 4 is a schematic vertical sectional view of the speed change gearing comprising a second embodiment, showing its essential portions; Fig. 5 is a schematic vertical sectional view of the speed change gearing comprising a third embodiment, showing its essential portions; Fig. 6 is a view as seen in the direction of arrows VI--VI in Fig. 5; Fig. 7 is a schematic vertical sectional view of the speed change gearing comprising a fourth embodiment, showing its essential portions;; Fig. 8 is a view as seen in the direction of arrowsVlll-Vlll in Fig. 7; Fig. 9 is a schematic vertical sectional view of the speed change gearing comprising a fifth embodiment, showing its essential portions; and Fig. 10 is a schematic vertical sectional view of the speed change gearing comprising a sixth embodiment, showing its essential portions.

Description of the Preferred Embodiments Preferred embodiments of the invention will now be described by referring to the accompanying drawings. Fig. 1 schematically shows a crusher of the ball type. The main body 1 comprises a rotary member 2 connected to a speed change gearing 5 through a coupling 4 and a pressure applying cylinder 3. The rotary member 2 comprises an upper ring 2a, a lower ring 2b and a plurality of balls 2c interposed between the upper and lower rings 2a and 2b, and the pressure applying cylinder 5 applies pressure to the balls 2c through the upper and lower rings 2a and 2b.

Fig. 2 shows the speed change gearing 5 in detail, wherein the numeral 6 designates a gear meshing with a pinion, not shown, and the numeral 7 designates an output shaft having the gear 6 secured thereto and supported at upper and lower ends by upper and lower gear casing members 9 and 10 respectively through radial bearings 8. Mounted between the gear 6 and the lower gear casing member 10 is a thrust bearing 11 for bearing a thrust load applied to the gearing by the main body 1 of the crusher including an inner race 1 a positioned against the gear 6 and an outer race 1 b positioned against the lower gear casing member 10. The inner race 1 a and outer race 1 b are formed as of bearing steel.

Fig. 3 shows a first embodiment wherein a metal layer 1 2 of high wear resistance is provided to the surface of the lower gear casing member 10 in contact with the outer race 11 b of the thrust bearing 1 The metal layer 12 may be formed as by sulfonitriding treatment. More specifically, the metal layer 12 is a low alloy steel (0.2-0.4% C) containing 0.53.0% Cr and 0.15-0.50% Mo, either singly or in combination, which is subjected to sulfonitriding treatment, so that the metal layer 12 has initial adaptation characteristics and high surface hardness.

Alternatively, the metal layer 12 may be formed by subjecting a low alloy steel including Cr, mo and Al either singly or in combination, to nitriding treatment, or by subjecting a spheroidal graphite cast iron to surface hardening treatment relying or high frequency hardening or fiame hardening.

Either of these processes can impart similar characteristics to the metal layer 12. The radial bearings 8 and the thrust bearing 11 receive a supply of lubricant from a charge of lubricant 13 in the lower gear casing member 10.

In the speed change gearing 5 of the crusher constructed as aforesaid, drive force from a motor, not shown, is transmitted through the gear 6 meshing with the pinion, not shown, to the output shaft 7 which rotates the rotary member 2 of the main body 1 of the drusher through the coupling 4. A charge of coal or other solid material inserted from outside between the upper and lower rings 2a and 2b is crushed by the balls 2c of the rotary member 2 as the latter rotates. At this time, pressure is applied to the rotary section by the pressure applying cylinder 3 so that the balls 2c rotate while pressure is applied thereto.

Thus a thrust load is applied to the thrust bearing 11 by the rotary member 2 of the main body 1 of the crusher through the output shaft 7. The gearing is usually constructed such that the thrust load is borne by the lower gear casing member 10. However, when crusing of coal or other solid material is carried out in the main body 1 of the crusher under severe conditions, the thrust load applied to the thrust bearing 11 would be increased in magnitude and wear would be caused on the lower gear casing 10 positioned against the thrust bearing 11.

Application of a high thrust load to the thrust bearing 11 would cause the thrust bearing 11 and lower gear casing member 10 to move radially a small distance relative to each other and cause a change to occur in the pressure applied to the inte:4ace. This might cause exfoliation and other phenomena of wear on the interface, particularly on the surface of the lower gear casing member 10. To avoid this phenomenon, the invention provides the metal layer 12 2 of high wear resistance to the surface of the lower gear casing member 10.It has been ascertained in actual practice that the provision of the surface of the lower gear casing member 10 with the metal layer 1 2 by sulfonitriding treatment has the effect of reducing the amount of wear to 1/20 the wear caused on the surface of the lower gear casing member 10 receiving no surface treatment.

Fig. 4 shows a second embodiment in which an annular spacer 14 is detachably supported on the lower gear casing member 10 as through bolts so that the spacer 14 is positioned against the outer race 1 b of the thrust bearing 11. The spacer 14 is formed on its surface with a metal layer 1 5 of high wear resistance by sulfonitriding treatment given in the same manner as described by referring to the first embodiment.Like the first embodiment, this embodiment is capable of avoiding the occurrence of wear on the surface of the lower gear casing member 10, and also offers the advantage that replacements of parts in maintenance can be facilitated. when the annular space 14 is divided radially into a plurality of pieces which are each supported by the lower gear casing member 10, replacements of the parts can be further facilitated.

Figs. 5 and 6 show a third embodiment in which a plurality of oil grooves 16 are formed on the surface of the lower gear casing member 10 on which the metal layer 12 is also formed.

Lubricant is fed to the oil grooves 1 6 from the charge of lubricant 13 in the lower gear casing member 10. The provision of the oil grooves 6 on the surface of the lower gear casing member 10 enables the lubricant to be smoothly fed to the surface of the lower gear casing member 10 in enough quantity to avoid seizure and wear, even if no enough gap is formed between the outer race 1 b of the thrust bearing 11 and the surface of the lower gear casing member 10.

Figs. 7 and 8 show a fourth embodiment in which the spacer 14 formed on its surface with the metal layer 1 5 is also formed with a plurality of oil grooves 1 7 thereon for receiving a supply of lubricant from the charge of lubricant 13 in the lower gear casing member 10. The provision of the oil grooves 1 7 on the surface of the spacer 14 is conductive to prevention of the occurrence of seizure between the thrust bearing 1 1 and the spacer 14.

A fifth embodiment shown in Fig. 9 is constructed such that the thrust bearing 11 is mounted between the coupling 4 and the upper gear casing member 9. The metal layer 12 of high wear resistance is formed on the surface of the upper gear casing 9 positioned against the outer race 1 b of the thrust bearing 11.

Fig. 10 shows a sixth embodiment in which the thrust bearing 11 is mounted such that the inner race 1 a thereof is positioned against the lower gear casing member 10 and the outer race 1 b thereof is positioned against the gear 6, the metal layer 12 is formed on the lower gear casing 10 positioned against the inner race 1 a of the thrust bearing 1 The spacer 14 formed with the oil grooves 1 6 or the spacer divided into a plurality of pieces may be mounted between the inner race 1 a of the thrust bearing 11 and the lower gear casing member 10.

From the foregoing description, it will be appreciated that the phenomena of wear, such as exfoliation, fretting, etc., occurring between a thrust bearing and a member positioned thereagainst can be avoided, thereby enabling a speed change gearing of a prolonged service life to be obtained.

Claims

1. A speed change gearing of a crusher connected to the lower end of a main body of the crusher for crusing solid material, wherein one of a race of a thrust bearing or a part positioned against the race of the thrust bearing is subjected to surface treatment to increase the wear resistance of its surface.

2. A speed change gearing as claimed in claim 1, wherein said surface treatment is sulfonitriding.

3. A speed change gearing as claimed in claim 1, wherein said surface treatment is nitriding.

4. A speed change gearing as claimed in claim 1, wherein said thrust bearing is interposed between a gear and a lower gear casing member.

5. A speed change gearing as claimed in claim 1, wherein said thrust bearing is interposed between a coupling and an upper gear casing member.

6. A speed change gearing as claimed in claim 1, wherein said race of the thrust bearing is an outer race, and said part positioned against the race of the thrust bearing is a lower gear casing member.

7. A speed change gearing as claimed in claim 1, wherein said race of the thrust bearing is an outer race, and said part positioned against the race of the thrust bearing is a spacer.

8. A speed change gearing as claimed in claim 7, wherein said spacer is radially divided into a plurality of pieces.

9. A speed change gearing as claimed in claim 6, wherein said lower gear casing member is formed on its surface with oil grooves.

10. A speed change gearing as claimed in claim 7, wherein said spacer is formed on its surface with oil grooves.

11. A speed change gearing as claimed in claim 8, wherein each of the pieces of the divided spacer is formed on its surface with oil grooves.

12. A speed change gearing as claimed in claim 1, wherein said race of the thrust bearing is an inner race, and said part positioned against the race of the thrust bearing is a lower gear casing member.

1 3. A speed change gearing as claimed in claim 1, wherein said race of the thrust bearing is an inner race, and said part positioned against the race of the thrust bearing is a spacer.

14. A speed change gearing as claimed in claim 13, wherein said spacer is radially divided into a plurality of pieces.

1 5. A speed change gearing as claimed in claim 12, wherein said lower gear casing member is formed on its surface with oil grooves.

1 6. A speed change gearing as claimed in claim 13, wherein said spacer is formed on its surface with oil grooves.

1 7. A speed change gearing as claimed in claim 14, wherein each of the pieces of the radially divided spacer is formed on its surface with oil grooves.

1 8. A speed change gearing as claimed in claim 1, wherein said race of the thrust bearing is an outer race, and said part positioned against the race of the thrust bearing is an upper gear casing member.

19. A speed change gearing as claimed in claim 1, wherein said race of the thrust bearing is an inner race, and said part positioned against the race of the thrust bearing is an upper gear casing member.

20. A speed change gearing substantially as hereinbefore described with reference to and as shown by Figures 3 to 10 of the accompanying drawings.