FRETTING WEAR REDUCTION IN INTERFERENCE FIT OF CONE CRUSHER HEAD

Abstract

A system, cone crusher and its main shaft that includes an interference fit section for supporting a crusher head. The interference fit section has a nominal interference fit diameter D.sub.if; a bottom shaft section extending between a bottom end of the main shaft and the interference fit section, and having a bottom part and a neck part. The bottom part has a bottom part length L.sub.bp and a bottom part diameter D.sub.bp that is constant below the neck part on at least 50% of the bottom part length L.sub.bp. The neck part has a neck part diameter growing towards the interference fit section. The main shaft has a main shaft length L.sub.ms. L.sub.ms.sup.1.3/D.sub.if is at most 40 mm.sup.1.3. D.sub.bp.sup.1.421/D.sub.if is at most 9.0 mm.sup.0.421.

Claims

1-15. (canceled)

16. A main shaft of a cone crusher, comprising: an interference fit section for supporting a crusher head, the interference fit section having a nominal interference fit diameter D.sub.if; a bottom shaft section extending between a bottom end of the main shaft and the interference fit section; the bottom shaft section comprising a bottom part and a neck part; wherein the bottom part has a bottom part length L.sub.bp and a bottom part diameter D.sub.bp that is constant below the neck part on at least 50% of the bottom part length L.sub.bp; the neck part has a neck part diameter that is growing towards the interference fit section; the main shaft has a main shaft length L.sub.ms; wherein for reducing fretting wear in the interference fit section, L.sub.ms.sup.1.3/D.sub.if is at most 40 mm.sup.0.3; and D.sub.bp.sup.1.421/D.sub.if is at most 9.0 mm.sup.0.421.

17. The main shaft of claim 16, wherein the main shaft length L.sub.ms is at least 1200 mm.

18. The main shaft of claim 16, wherein D.sub.bp.sup.1.421/D.sub.if is at most 8.0 mm.sup.0.421.

19. The main shaft of claim 17, wherein D.sub.bp.sup.1.421/D.sub.if is at most 8.0 mm.sup.0.421.

20. The main shaft of claim 16, wherein D.sub.bp.sup.1.421/D.sub.if is at least 6.4 mm.sup.0.421.

21. The main shaft of claim 17, wherein D.sub.bp.sup.1.421/D.sub.if is at least 6.4 mm.sup.0.421.

22. The main shaft of claim 16, wherein L.sub.ms.sup.1.3/D.sub.if is at least 30 mm.sup.0.3.

23. The main shaft of claim 17, wherein L.sub.ms.sup.1.3/D.sub.if is at least 30 mm.sup.0.3.

24. The main shaft of claim 16, wherein the interference fit section is longitudinally continuous.

25. The main shaft of claim 16, wherein the main shaft is configured to laterally support the crusher head only by the interference fit section.

26. The main shaft of claim 16, wherein at maximum the neck part diameter meets the interference fit section diameter.

27. The main shaft of claim 16, wherein the neck part is progressively curving for reducing stress concentration.

28. A system comprising: a main shaft comprising: an interference fit section for supporting a crusher head, the interference fit section having a nominal interference fit diameter D.sub.if; a bottom shaft section extending between a bottom end of the main shaft and the interference fit section; the bottom shaft section comprising a bottom part and a neck part; wherein the bottom part has a bottom part length L.sub.bp and a bottom part diameter D.sub.bp that is constant below the neck part on at least 50% of the bottom part length L.sub.bp; the neck part has a neck part diameter that is growing towards the interference fit section; the main shaft has a main shaft length L.sub.ms; wherein for reducing fretting wear in the interference fit section, L.sub.ms.sup.1.3/D.sub.if is at most 40 mm.sup.0.3; and D.sub.bp.sup.1.421/D.sub.if is at most 9.0 mm.sup.0.421; and a cone crusher head configured for interference fit attaching to the main shaft interference fit section.

29. The system of claim 28, wherein the cone crusher head has a cone sector of at least 45 degrees.

30. The system of claim 28, wherein the cone crusher head has a cone sector of at least 55 degrees.

31. The system of claim 28, wherein an interference fit section diameter D.sub.if is least 40% of a cone crusher head diameter D.sub.ch.

32. The system of claim 29, wherein an interference fit section diameter D.sub.if is least 40% of a cone crusher head diameter D.sub.ch.

33. The system of claim 30, wherein an interference fit section diameter D.sub.if is least 40% of a cone crusher head diameter D.sub.ch.

34. The system of claim 28, wherein the cone crusher head is attached to the main shaft.

35. A cone crusher comprising: a main shaft comprising: an interference fit section for supporting a crusher head, the interference fit section having a nominal interference fit diameter D.sub.if; a bottom shaft section extending between a bottom end of the main shaft and the interference fit section; the bottom shaft section comprising a bottom part and a neck part; wherein the bottom part has a bottom part length L.sub.bp and a bottom part diameter D.sub.bp that is constant below the neck part on at least 50% of the bottom part length L.sub.bp; the neck part has a neck part diameter that is growing towards the interference fit section; the main shaft has a main shaft length L.sub.ms; wherein for reducing fretting wear in the interference fit section, L.sub.ms.sup.1.3/D.sub.if is at most 40 mm.sup.0.3; and D.sub.bp.sup.1.421/D.sub.if is at most 9.0 mm.sup.0.421; and a cone crusher head configured for interference fit attaching to the main shaft interference fit section.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0041] Some example embodiments will be described with reference to the accompanying Figures, in which:

[0042] FIG. 1 schematically shows a main shaft of an example embodiment;

[0043] FIG. 2 schematically shows a system of main shaft and a cone crusher head of an example embodiment; and

[0044] FIG. 3 schematically shows a cone crusher comprising the system of FIG. 2.

DETAILED DESCRIPTION

[0045] In the following description, like reference signs denote like elements or steps.

[0046] FIG. 1 schematically shows a main shaft 100 of an example embodiment. FIG. 1 shows some portions and dimensions of the main shaft (mms), such as a thread 110 for attaching a wear part (not shown) by a nut (not shown); an interference fit section 120; a bottom shaft section 130 that comprises a bottom part 134 and a neck part 132 between the bottom part 134 and the interference fit section (120).

[0047] FIG. 1 shows some dimensions such L stands for length, D stands for diameter, and a subscript indicates the object in question.

[0048] In FIG. 1, the bottom part has a constant diameter over its entire length, notwithstanding some possible rounding at the very bottom end. In some other embodiments, the bottom part may have some portions of greater or smaller diameter, but the diameter of the bottom part is present on at least 50% of the length of the bottom part. It is also possible that this at least 50% is formed of two or more portions.

[0049] The interference fit section has a nominal diameter D.sub.if that is configured to fit for cone crusher heads of a shaft opening having the nominal diameter D.sub.if. In an embodiment, one or both ends of the interference fit section have slightly greater nominal diameter, e.g., in the range of tens or hundreds of parts per million in comparison to the nominal diameter D.sub.if.

[0050] As in FIG. 1, the main shaft comprises in an example embodiment only one interference fit section for attaching the crusher head. Preferably, the interference fit section is longitudinally continuous.

[0051] As shown in FIG. 1, the neck part has a neck part diameter that is growing towards the interference fit section. In FIG. 1 embodiment, the neck part grows to the nominal diameter, or in other words, the surface of the main shaft deviates from a perpendicular plane formed with relation to an axial direction of the main shaft, all the way from the centre of the interference fit section 120 over the neck part.

[0052] As also shown in FIGS. 1 and 2, the main shaft 100 can be configured to laterally support or at least to laterally engage with the crusher head only by the interference fit section.

[0053] In the main shaft 100 of FIG. 1, fretting wear is reduced in the interference fit section by forming the interference section and the bottom part such that ratio L.sub.ms.sup.1.3/D.sub.if is at most 40 mm.sup.0.3; while the dimensions of the interference fit section 120 and of the bottom part are such that D.sub.bp.sup.1.421/D.sub.if is at most 9.0 mm.sup.0.421.

[0054] It is appreciated that the main shaft 100 and a cone crusher head will form a system. The greater the diameter is at the interference fit section, the wider an opening is required in the crusher head and thus the thinner the structures will be there. It would appear intuitive to assume that since the shaft is squeezed on all sides by the interference fit attached crusher head, the system will become more prone to deformations when the diameter is increased. Surprisingly, though, it was found that in two different commercially available cone crushers, the sliding distance under different loads and fretting wear were reduced in the range of tens percent or even more. While the entire force system is not fully understood, it is believed that the fretting wear can be reduced ratio L.sub.ms.sup.1.3/D.sub.if being at most 40 mm.sup.0.3. In an example embodiment, the ratio L.sub.ms.sup.1.3/D.sub.if is at most 37.5 mm.sup.0.3. In an example embodiment, the ratio L.sub.ms.sup.1.3/D.sub.if is at least 30 mm.sup.0.3. In another example embodiment, the ratio L.sub.ms.sup.1.3/D.sub.if is at least 32.5 mm.sup.0.3. The second condition, D.sub.bp.sup.1.421/D.sub.if, is expected to operate through dynamics over the bottom part of the main shaft that extend over the interference fit section 120. In an example embodiment, this ratio is at most 8.0 mm.sup.0.421. In an example embodiment, this ratio is at most 7.7 mm.sup.0.421. In an example embodiment, this ratio is at least 6.4 mm.sup.0.421 or at least 6.9 mm.sup.0.421.

[0055] FIG. 2 shows a system 200 of the main shaft 100 and a cone crusher head 210 of an example embodiment. FIG. 2 also shows an inner wear part 220 attached to the cone crusher head 210 by a nut 230. FIG. 2 also illustrates by dashed extensions a cone sector of the cone crusher head 210. Moreover, FIG. 2 shows a cone crusher head diameter D.sub.ch and a cone crusher head length L.sub.ch that is the longitudinal length or height of the cone crusher head 210.

[0056] FIG. 3 schematically shows a cone crusher 300 comprising the system of FIG. 2, comprising the main shaft 100, the cone crusher head 210, an outer wear part 210 and a crushing chamber 320 between the inner and outer wear parts 210, 310.

[0057] Various embodiments have been presented. It should be appreciated that in this document, words comprise; include; and contain are each used as open-ended expressions with no intended exclusivity.

[0058] The foregoing description has provided by way of non-limiting examples of particular implementations and embodiments a full and informative description of the best mode presently contemplated by the inventors for carrying out the invention. It is however clear to a person skilled in the art that the invention is not restricted to details of the embodiments presented in the foregoing, but that it can be implemented in other embodiments using equivalent means or in different combinations of embodiments without deviating from the characteristics of the invention.

[0059] Furthermore, some of the features of the afore-disclosed example embodiments may be used to advantage without the corresponding use of other features. As such, the foregoing description shall be considered as merely illustrative of the principles of the present invention, and not in limitation thereof. Hence, the scope of the invention is only restricted by the appended patent claims.