Mechanically improved wear elements for earth moving machines

Abstract

A wear element for an earth moving machine, comprising: a body adapted for coupling with another wear element; at least one surface of the body having compressive residual stresses introduced therein; and the at least one surface being free of weld seams. A method for treating at least one wear element for an earth moving machine, comprising applying a compressive contact treatment to the at least one wear element whereby a tool contacts at least one surface of the at least one wear element for introducing compressive residual stresses therein, wherein each wear element of the at least one wear element comprises a body adapted for coupling with at least another wear element; with the at least one surface being free of weld seams. Also, a wear assembly, an earth moving machine and a method for manufacturing at least one wear element for an earth moving machine.

Description

[0001] MECHANICALLY IMPROVED WEAR ELEMENTS FOR EARTH MOVING MACHINES

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to the field of earth moving machines. More particularly, the present disclosure relates to, but is not limited to, wear elements or ground engaging tools for earth moving machines with superior mechanical properties and methods for mechanically treating wear elements to achieve such superior mechanical properties.

[0004] BACKGROUND

[0005] Earth moving machines such as excavators or loaders or cutterheads, for example, for working in construction sites, mining, dredging, etc., expose the wear elements thereof, also referred to in the present disclosure as ground engaging tools, to forces, abrasion and wear.

[0006] Consequently, the wear elements must be frequently replaced with new wear elements or, sometimes, undergo repairment to put them in working condition again. The latter occurs less frequently because, generally, wear elements are treated as consumable components of an earth moving machine. This means that once the wear elements are too worn or damaged, they are detached (i.e. , decoupled) from the earth moving machine and decommissioned, leaving the free spot to a fresh wear element.

[0007] The repair tasks and new wear elements are costly, not just due to the resource costs thereof, but also due to the non-productivity of the earth moving machine during maintenance. Repairment and replacement of wear elements requires halting operation of the earth moving machine, and also positioning the different components of the machine in a particular way to give access to personnel. Oftentimes, these tasks also require moving the machine to premises where repairment and / or replacement are conducted, thus making the whole process even less efficient.

[0008] Accordingly, there is an interest in improving one or more mechanical properties of wear elements, especially mechanical property(ies) related to strength and durability, so as to lengthen their operating life. Known developments have focused on new alloys for the wear elements that increased, e.g., fatigue strength and, thus, the useful life of the wear elements. Some alternative known developments have focused on premature detection of worsening in the condition of the wear elements to schedule predictive maintenance tasks, which do not avoid halting operation of the machine but either reduce the total halted time or fix the wear elements thereby lengthening their useful life.

[0009] Such developments do not properly solve the aforesaid problems. Therefore, improving one or more mechanical properties of wear elements is still sought. DESCRIPTION

[0010] A first aspect relates to a wear element for an earth moving machine. The wear element (e.g., cast lip, whisler lip, plate lip, adapter, intermediate adapter, tooth bar, shroud, cutterhead, cast corner, etc.) comprises a body adapted for coupling with at least another wear element.

[0011] At least one surface of the body may have compressive residual stresses introduced therein. In this sense, at least a portion of the body that includes the at least one surface may have additional compressive residual stresses than those originally present. The introduction of the compressive residual stresses may be caused, for instance, by the application of compressive contact treatment on the at least one surface with a tool, like, e.g., by conducting a method in accordance with an aspect below, thereby introducing additional compressive residual stresses than those caused by the manufacturing of the body and the wear element. In this sense, introduction of compressive residual stresses in at least one surface is to be understood as providing new compressive residual stresses not present in the at least one surface upon manufacturing (e.g., a casting process, a forging process) the body and the wear element.

[0012] The at least one surface that may have the introduced compressive residual stresses is preferably free of welds, namely, the at least one surface does not comprise weld seams. Accordingly, the at least one surface is continuous as it includes one or more surfaces of a same part (as opposed to including one or more surfaces of different parts welded together).

[0013] The at least one surface may, additionally or alternatively, comprise a change in width of cross-section. The width of the cross-section in the at least one section becomes larger or smaller when moving along a direction thereon, which occurs in regions of the body whose area and / or volume changes owing to the shape thereof for formation of various parts or at interfaces between parts, e.g., interface between main body of a cast lip and nose(s), interface between main body of a cast lip and lateral wall(s), etc. In this sense, the at least one surface may, additionally or alternatively, comprise a curved surface of the body between two portions thereof with different cross-section widths.

[0014] Introduction of compressive residual stresses in regions that are free of weld seams and / or have a variable cross-section width and / or have curved surfaces between portions with variable cross-section width mechanically improves the body because, for example, greater fatigue strength and / or greater stress corrosion cracking may be attained. Some harsh environments in which earth moving machines operate have corrosive characteristics, thus increasing the stress corrosion cracking may also be beneficial. The introduction of these stresses may be achieved by applying a compressive contact treatment, such as, e.g., high-frequency impact treatment, on the at least one surface. By way of example, the body and, particularly, the at least one surface may be subjected to multiple high-frequency mechanical impacts to introduce compressive residual stresses. In such cases, the at least one surface may consequently feature rugosity such that it has a plurality of valleys and / or a plurality of peaks thereon.

[0015] In some embodiments, the body comprises at least one nose.

[0016] Each nose of the at least one nose protrudes from the body along a protruding direction that may go from a rear end towards a front end. The front end is closest to where points or teeth are arranged in digging implements with wear elements coupled therewith; accordingly, the front end is the end closest to the engaged material during operation of the earth moving machine. The rear end is generally closest to digging implements of the earth moving machine.

[0017] In some embodiments, the at least one surface comprises a perimeter defining a cavity (e.g., hole) for receiving a locking pin for coupling another wear element to the wear element.

[0018] The contour of the region where the cavity is formed is prone to cracking. An increase of at least one mechanical property at least in such contour increases the expected lifetime of the wear element.

[0019] In some embodiments, the at least one surface comprises an interface of the body from which the at least one nose protrudes.

[0020] The protrusion of each nose may reduce the strength thereof, especially at the interface between the nose and the main body, owing to a reduction in cross-section width. Even if the noses are integrally formed with the body, the shape variations in the geometry due to the noses and the reduction in cross-section width have a toll on the mechanical strength, such as, e.g., fatigue strength. An increase of at least one mechanical property at least at such interface increases the expected lifetime of the wear element.

[0021] In some embodiments, the body comprises a cast lip.

[0022] In some embodiments, the wear element is a cast lip.

[0023] A cast lip for an earth moving machine is not to be replaced very often having regard how costly it is to manufacture and to couple with digging implements. A cast lip is an important wear element for supporting other wear elements. Hence, increasing the expected lifetime of a cast lip is especially beneficial.

[0024] In some embodiments, the at least one surface comprises at least one cavity between a pair, or each pair, of neighboring noses protruding from the body.

[0025] Cavities connecting neighboring noses have surfaces that tend to directly or indirectly receive loads from the engaged material. When no shrouds are arranged covering the cavities, the contact with the material is direct and damages the cavity surfaces more than when indirectly receiving the loads, which is when a shroud is arranged on the cavity to protect it from the direct contact of the material.

[0026] These cavities are, oftentimes, a location where cracks start to appear and propagate through the cast lip. Increased mechanical strength reduces the likelihood of the cast lip breaking, or at least doing so in a shorter period of time.

[0027] In some embodiments, the at least one surface comprises at least one interface between the cavity and a nose of the pair of neighboring noses. In some cases, the at least one interface is on a side opposite a side from which lateral walls protrude from the body. That is to say, the at least one interface is on an underside of the body that is more prone to contacting an engaged material with high friction and loads than an upper side of the body.

[0028] A portion extending from a nose to a cavity that connects said nose with a neighboring nose is also prone to getting damaged and cracking. Sometimes these portions may not be covered with protective devices, or at least not entirely. Therefore, mechanical improvement of the at least one surface is convenient.

[0029] In some embodiments, the at least one surface comprises at least one edge at an end of the cavity along a direction of protrusion of the pair of neighboring noses. Namely, a front end of the cavity, which is the end most exposed to the engaged material, may also be mechanically improved.

[0030] In some embodiments, the at least one surface comprises an interface between at least one lateral wall of the body and a portion of the body from which at least one lateral wall protrudes.

[0031] In some embodiments, the at least one surface comprises a perimeter defining a through hole for receiving a locking pin for coupling another wear element to the wear element.

[0032] In some embodiments, the at least one surface comprises at least one lateral surface of at least one stabilizing nose.

[0033] In some embodiments, the at least one surface comprises at least one surface adapted to contact another wear element. In some embodiments, the at least one surface comprises a surface of at least one contact projection.

[0034] Stabilizing noses and / or contact projections may be part of, for example, a body of a whisler lip.

[0035] In some embodiments, the body comprises a plate lip or an adapter or an intermediate adapter or a tooth bar or a shroud or a cutterhead or a cast corner. In some embodiments, the wear element is a plate lip or an adapter or an intermediate adapter or a tooth bar or a shroud or a cutterhead or a cast corner.

[0036] In some embodiments, the compressive residual stresses of the body are introduced by a compressive contact treatment on the at least one surface.

[0037] The compressive contact treatment may correspond, for example, to a method as described in the fourth aspect. The compressive contact treatment may be conducted with a suitable tool to that end, for instance to conduct, e.g., ultrasonic peening, hammer peening or needle peening.

[0038] In some embodiments, a difference in depth between valleys and peaks of a plurality of valleys and a plurality of peaks on the at least one surface is greater than or equal to 0.10 mm and smaller than or equal to 0.50 mm. In some embodiments, said difference is greater than or equal to 0.15 mm and smaller than or equal to 0.35 mm.

[0039] In some embodiments, the concentration of compressive residual stresses in the at least one surface is such that strength of the compressive residual stresses is greater than or equal to 0.80 times an original elastic limit thereof (i.e. , that of the at least one surface prior to introduction of the compressive residual stresses), namely, the yield strength thereof, and / or greater than or equal to 0.80 times an elastic limit of a portion of the body not including the at least one surface, namely, a portion not having the compressive residual stresses introduced therein (and, thus, just having the compressive residual stresses due to the manufacturing process).

[0040] In some embodiments, the concentration of compressive residual stresses in the at least one surface is such that the strength of the compressive residual stresses is smaller than or equal to 1.50 times the original elastic limit thereof and / or smaller than or equal to 1 .50 times the elastic limit of a portion of the body not including the at least one surface.

[0041] In some embodiments, a hardness of the at least one surface is greater, such as at least 10% greater, than: a hardness of the at least one surface prior to introduction of the compressive residual stresses, and / or a hardness of a portion of the body not including the at least one surface. In some embodiments, said hardness is at least 15% greater. The hardness may correspond to a hardness measurable with Vickers hardness test, namely, microhardness test.

[0042] In some embodiments, the at least one surface comprises a hardness greater than or equal to 300 HV (hardness Vickers). In some embodiments, said hardness is greater than or equal to 400 HV, and in some cases greater than or equal to 450 HV. In some embodiments, said hardness is smaller than or equal to 600 HV. In some embodiments, said hardness is smaller than or equal to 400 HV.

[0043] In some embodiments, the at least one surface prior to introduction of the compressive residual stresses and / or a portion of the body not including the at least one surface comprise / s a hardness greater than or equal to 250 HV. In some embodiments, said hardness is greater than or equal to 300 HV, and in some cases greater than or equal to 400 HV. In some embodiments, said hardness is smaller than or equal to 450 HV. In some embodiments, said hardness is smaller than or equal to 325 HV.

[0044] In some embodiments, an elastic limit, i.e., yield strength, of the at least one surface is at least 10% greater than: an elastic limit of the at least one surface prior to introduction of the compressive residual stresses, and / or an elastic limit of a portion of the body not including the at least one surface. In some embodiments, said elastic limit is at least 15% greater and / or 20% greater.

[0045] In some embodiments, the body is or comprises a cast steel. In some embodiments, the cast steel is a NiCrMo cast steel. In some embodiments, the NiCrMo cast steel is a low or a medium carbon low-alloyed NiCrMo cast steel.

[0046] A second aspect relates to a wear assembly. The wear assembly comprises at least one wear element (e.g., a wear element, two wear elements, three wear elements, or even more than three wear elements) as described in the first aspect.

[0047] In some embodiments, the wear assembly is or comprises digging implements.

[0048] Each wear element is directly or indirectly coupled with the digging implements, namely with a body thereof. Therefore, the wear elements may be coupled with the digging implements by attaching them thereto, or be coupled with the digging implements by means of other wear elements in turn coupled with the digging implements. For example, the at least one wear element comprises an intermediate adapter that is coupled with another wear element such as, e.g., a plate lip, the latter being coupled with the digging implements.

[0049] The coupling or attachment of the wear elements is any suitable in the field of earth moving machines, for example, with one or more of: weld seams, engagement, fixing pins, and wedges.

[0050] A third aspect relates to an earth moving machine. The earth moving machine comprises at least one wear element (e.g., a wear element, two wear elements, three wear elements, or even more than three wear elements) as described in the first aspect. Additionally or alternatively, the earth moving machine comprises at least one wear assembly (e.g., a wear assembly, two wear assemblies, three wear assemblies, or even more than three wear assemblies) as described in the second aspect.

[0051] A fourth aspect relates to a method for treating at least one wear element (e.g., a wear element, two wear elements, three wear elements, or even more than three wear elements) for an earth moving machine. The method comprises applying a compressive contact treatment to the at least one wear element whereby a tool contacts at least one surface of the at least one wear element for introducing compressive residual stresses therein.

[0052] In some embodiments, the method comprises providing each wear element of the at least one wear element prior to applying the compressive contact treatment.

[0053] A fifth aspect relates to a method for manufacturing at least one wear element (e.g., a wear element, two wear elements, three wear elements, or even more than three wear elements) for an earth moving machine. The method comprises manufacturing the at least one wear element. The method comprises applying a compressive contact treatment to the at least one manufactured wear element whereby a tool contacts at least one surface of the at least one wear element for introducing compressive residual stresses therein.

[0054] In each of the fourth and fifth aspects, the compressive contact treatment is conducted with a suitable tool known in the art, e.g., a tool for ultrasonic peening, a tool for hammer peening or a tool for needle peening. As a result of the treatment, the at least one surface is at least plastically deformed. In some embodiments, the plastic deformation is between 5% and 25%.

[0055] Also, in each of the fourth and fifth aspects, each wear element of the at least one wear element comprises a body adapted for coupling with at least another wear element. And the at least one surface may be as described with reference to the wear element of the first aspect. That is to say, the at least one surface may be free of weld seams or transitions, and / or comprise a change in width of cross-section and / or comprise a curved surface of the body between two portions thereof with different cross-section widths.

[0056] In some embodiments, the manufacturing comprising casting or forging.

[0057] In some embodiments of the fourth and fifth aspects, each wear element of the at least one wear element is a wear element as described in the first aspect. In some embodiments, each wear element of the at least one wear element is part of a wear assembly as described in the second aspect and / or is part of an earth moving machine as described in the third aspect.

[0058] In some embodiments of the fourth and fifth aspects, applying the compressive contact treatment comprises: a first application of the compressive contact treatment whereby the tool has a first peening intensity; and a second application of the compressive contact treatment whereby the tool has a second peening intensity.

[0059] Up to two applications of the compressive contact treatment increase mechanical properties such as fatigue strength and stress corrosion cracking on the treated surfaces. Further, a reduced number of applications also reduces the treating and manufacturing times of the wear elements, thereby increasing the productivity of the associated methods.

[0060] In some embodiments of the fourth and fifth aspects, the second application is posterior to the first application, and the first peening intensity is greater than the second peening intensity.

[0061] In some embodiments of the fourth and fifth aspects, the first peening intensity is between three (3) and five (5) times greater than the second peening intensity.

[0062] A less intense (in comparison with the first peening application) second peening application further improves the mechanical properties of the at least one surface.

[0063] The effect of this improvement generally becomes greater when the difference in intensities is between 3 and 5 times, both values being also included in the range.

[0064] In some embodiments of the fourth and fifth aspects, the method comprises deburring the at least one surface. The deburring is posterior to the applying of the compressive contact treatment.

[0065] The compressive contact treatment may produce burr at edges of application of the treatment, which in some occasions has a negative impact on the mechanical performance of the at least one wear element due to worse mechanical properties. Deburring such burr removes material from the at least one wear element, which although may not be convenient because of material loss, it leaves a mechanically superior surface exposed so that it is this one contacting the engaged material.

[0066] In some embodiments of the fourth and fifth aspects, the deburring is conducted with a milling machine with a milling diameter greater than a diameter of the tool of the compressive contact treatment.

[0067] In some embodiments of all the aspects above, the tool for applying the compressive contact treatment applies ultrasonic impact peening and a head of the tool comprises multiple tool heads.

[0068] In some embodiments of all the aspects above, one or more tool heads of the tool for applying the compressive contact treatment has a radius between 1.5 mm and 7.5 mm.

[0069] In some embodiments of all the aspects above, only a portion of the at least one surface of the body has compressive residual stresses introduced therein.

[0070] Mechanical improvement of just part of the at least one surface may be sufficient for substantially increasing the lifetime of the wear element as the mechanical improvement is made just at the portion that is subjected to loads that may cause fatigue or cracking. The compressive residual stresses increase the resistance to fatigue and corrosion cracking.

[0071] By limiting the introduction of the compressive residual stresses in the portion, the manufacturing and / or treatment of the wear element is more cost-effective as no compressive residual stresses are introduced in other parts of the body and the at least one surface less likely to cause failure when subjected to loads during operation of the earth moving machine. In some embodiments of all the aspects above, the portion of the at least one surface is free of weld seams and / or has a variable cross-section width and / or has curved surfaces.

[0072] A portion free of weld seams, and / or with variable cross-section width, and / or with curved surfaces may be more prone to fatigue or cracking, thereby benefiting from the introduction of compressive residual stresses.

[0073] In some embodiments of all the aspects above, the at least one surface comprises at least one edge and / or at least one interface, such as, e.g., at least one interface between two portions of the at least one surface with different geometries that provide the interface(s) with, e.g., a variable cross-section width and / or a curved surface.

[0074] In some embodiments of all the aspects above, the body is adapted to engage ground or material during operation of the earth moving machine.

[0075] The body is a body that the earth moving machine uses, at least partially, for ground engaging operations. Therefore, the body is subjected to loads and wear of greater intensity than other bodies as the body contacts the ground or material that is dug during operation of the earth moving machine. To this end, in some embodiments of all the aspects above, the wear element is adapted to engage the ground or the material during operation of the earth moving machine.

[0076] Such a body is a body that is typically replaced over time as it gets damaged, and even though it is exposed to the contact with the ground surface, increasing its lifetime as much as possible is beneficial for making replacement of the body less frequent.

[0077] In some embodiments of all the aspects above, the at least one surface is not a wear surface.

[0078] Among the surfaces that the body may have, wear surfaces, if any, are those that are adapted to contact the ground or material during operation of the earth moving machine. Other surface or surfaces that the body may have are not wear surfaces in the sense that they are not designed to come into contact with the ground or material. A surface not being a wear surface has the compressive residual stresses introduced therein as the mechanical improvement of such surface increases the lifetime of the wear element. Moreover, as such surface does not engage the ground or material, the compressive residual stresses are not lost or affected soon as no such engagement takes place.

[0079] BRIEF DESCRIPTION OF THE DRAWINGS

[0080] To complete the description and in order to provide for a better understanding of the disclosure, a set of drawings is provided. Said drawings form an integral part of the description and illustrate embodiments of the disclosure, which should not be interpreted as restricting the scope of the disclosure, but just as examples of how the disclosure can be carried out. The drawings comprise the following figures:

[0081] Figure 1 shows a cast lip assembled on digging implements in accordance with some embodiments.

[0082] Figure 2A shows a cast lip mechanically improved in accordance with some embodiments.

[0083] Figure 2B partially shows a detail of the cast lip of Figure 2A, mechanically improved in accordance with some embodiments.

[0084] Figures 3A shows another perspective view of the cast lip of Figure 2A, mechanically improved in accordance with some embodiments.

[0085] Figure 3B partially shows a detail of the cast lip of Figure 3A mechanically improved in accordance with some embodiments.

[0086] Figure 4 shows a detail of a cast lip mechanically improved in accordance with some embodiments.

[0087] Figure 5 shows a wear assembly comprising a plurality of wear elements, wherein at least one surface of one or more wear elements has been mechanically improved in accordance with some embodiments.

[0088] Figures 6A and 6B show different view perspectives of an intermediate wear element mechanically improved in accordance with some embodiments.

[0089] Figure 7 shows another example of a wear assembly comprised by a wear element and a plate lip adapter mechanically improved in accordance with some embodiments.

[0090] Figure 8 shows a detail of another example of a wear assembly comprised by a wear element and a whisler lip mechanically improved in accordance with some embodiments

[0091] Figure 9 shows a detail of a section view of the example of Figure 8.

[0092] DETAILED DESCRIPTION

[0093] For the sake of clarity only, all illustrated axes X, Y, Z are shown with same orientation in space with respect to the illustrated components. Such axes are example axes; it will be noted that any one arrangement of axes is possible without departing from the scope of the present disclosure.

[0094] Figure 1 shows an example of a cast lip 10 assembled on digging implements 60, such as, e.g., a bucket, in accordance with some embodiments.

[0095] The cast lip 10, which is a ground engaging tool, is arranged on a front end of the digging implements to protect the surface thereof from the wearing occurring during earth moving operations.

[0096] The cast lip 10 has a main body 13, a plurality of lateral walls 14 protruding from the main body 13, and a plurality of noses 15 protruding from the main body 13 too. The cast lip 10 includes a plurality of cavities 20 on the main body 13.

[0097] One or more surfaces of the cast lip 10 are mechanically improved in accordance with the present disclosure. The improvement of such one or more surfaces will be described in relation to the following Figures that depict cast lips 10 in accordance with some embodiments.

[0098] Figures 2A and 2B show a cast lip 10 mechanically improved in one or more surfaces thereof in accordance with some embodiments.

[0099] The cast lip 10 is coupled with digging implements of an earth moving machine at a rear end 11 of the cast lip 10. The cast lip 10 is adapted to have one or more wear elements coupled therewith at a front end 12. Particularly, wear elements may be coupled with noses 15 of the cast lip 10, which protrude from a main body 13 (illustrated in Figure 1 B with a dashed contour for the sake of clarity only) of the cast lip 10 along a protruding direction (according to illustrated axis X).

[0100] The cast lip 10 also has, on an upper side, which is that illustrated in Figures 1 , 2A and 2B, two lateral walls 14 protruding from the main body 13 along a protruding direction (according to illustrated axis Z). Further, the cast lip 10 has a plurality of cavities 20 each connecting a pair of neighboring noses 15. The cavities 20 receive, in some embodiments, wear elements in the form of shrouds for protection of the surface of the cavities 20.

[0101] Each nose 15 has one or more cavities 17 (e.g., one or more holes) for receiving at least one fixing device, such as a fixing pin, for reliably coupling a wear element attached thereto.

[0102] One or more interfaces between a nose 15 and the main body 13 may have the surface 16 thereof subjected to a compressive contact treatment whereby a tool introduces compressive residual stresses in the surface 16 of said one or more interfaces. The tool plastically deforms part of the treated surface for introducing the compressive residual stresses and increases a hardness thereof. Said surface 16 is free of weld transitions and has a change in cross-section width as the cross-section of the nose 15, adjacent to the interface, has a width smaller than a width of the cross-section of the region of the main body 13 adjacent to the interface.

[0103] The treated surfaces 16 may be one, some or all around the perimeter of the respective nose 15, for example in the four corner areas of the perimeter next to the interfaces. Sometimes, also the interface between a central rib of the nose 15 and the main body 13 has the surface 16 thereof treated, however such surface is generally sturdier than that outside a projection of the rib.

[0104] A surface 18 adjacent to where cavities 17 for fixing devices are formed may additionally or alternatively be treated for introduction of compressive residual stresses. The surface 18 is free of weld seams.

[0105] One or more interfaces between a lateral wall 14 and the main body 13 may also, additionally or alternatively, have the surface 19a, 19b thereof treated for introduction of compressive residual stresses. Said surfaces 19a, 19b of the one or more interfaces include lateral surfaces 19a, i.e. , at interfaces that extend mostly along a direction extending from the rear end 11 to a front end 12 (in a direction parallel to illustrated axis X), and / or frontal surfaces 19b, i.e., at interfaces that extend mostly along a direction extending from one side of the main body 13 to the other side of the main body 13 (that is to say, from one lateral wall 14 to the other, thus in a direction parallel to illustrated axis Y). The lateral surfaces 19a may be inner surfaces, i.e., the surfaces closest to the opposite lateral wall 14, and / or outer surfaces, i.e., the surfaces farthest away from the opposite lateral wall 14. The surfaces 19a, 19b at these interfaces are also free of weld seams as the lateral walls 14 are integrally formed with the main body 13. Additionally, there is a change in width of crosssections between the lateral wall 14 and the portion of the main body 13 adjacent to the interfaces, and which also has a curved surface therebetween.

[0106] One or more surfaces 23, 24 on the cavities 20 between noses 15 may, additionally or alternatively, be treated and, thus, have compressive residual stresses introduced therein. Particularly, the one or more surfaces may include surfaces 23 between a front end 22 of the cavities 20 and a side of a nose 15 that, apart from being free of welds, are curved between portions of the main body 13 and the nose 15 that have a changing width in crosssections thereof.

[0107] Another additional or alternative set of surfaces 24 that may be treated is at the front end 22 of the cavities 20. An edge surface 24 at the front-most part of the cavities 20 may have compressive residual stresses introduced therein, regardless of whether a shroud is to be arranged on the cavity 20 afterwards or not.

[0108] Figures 3A and 3B partially show a cast lip 10 mechanically improved in one or more surfaces thereof in accordance with some embodiments. The cast lip 10 illustrated may be the same of Figures 2A and 2B or a different cast lip 10. The cast lip 10 of Figures 3A and 3B is illustrated from an underside thereof, i.e., from a side opposite to that shown in Figures 2A and 2B.

[0109] One or more surfaces 25 that may be subjected to introduction of compressive residual stresses are in the cavities 20, particularly one or more curved surfaces 25 thereof defining an interface between the cavities 20 and the regions where the cavities 20 are formed. Such surfaces 25 may not be covered by a shroud when the latter is arranged, thus improving mechanical properties of these surfaces 25 is convenient.

[0110] Figure 4 partially shows a cast lip mechanically improved in one or more surfaces thereof in accordance with some embodiments.

[0111] The part of the cast lip illustrated is that of a nose 15, part of a lateral wall 14 and part of a cavity 20. Figure 4 shows a zoomed-in version of surfaces 16, 19a, 19b, 23, 24; one, some or all of these surfaces may be treated with a compressive contact treatment in different embodiments, for one, several or all noses 15, cavities 20 and lateral walls 14.

[0112] In some embodiments, all such surfaces 16, 19a, 19b, 23, 24 are treated and, optionally, surfaces 25 as shown with reference to Figures 3A and 3B are also treated. It will be noted that different combinations of these surfaces may be treated in different embodiments and they all fall within the scope of the present disclosure.

[0113] Although the wear elements illustrated in Figures 2A-2B, 3A-3B and 4 are cast lips 10, it will be noted that other wear elements, such as a plate lip, a shroud, an adapter, an intermediate adapter, a whisler lip, etc., may also have one or more surfaces thereof improved according to the present disclosure, and such wear elements also fall within the scope of the present disclosure. Such other wear elements may, like the cast lips 10, be adapted for engaging ground or material during operation of the earth moving machine, and / or have a body adapted to that end.

[0114] The aforementioned surfaces 16, 19a, 19b, 23-25, which are portions of the entire surface of the cast lip 10, are part of a ground engaging tool that generally comes into contact with ground or material during operation of the earth moving machine. Some or all of these surfaces 16, 19a, 19b, 23-25 are not wear surfaces as they generally do not contact the ground or material when the wear element contacts the ground or material, in fact, some or all of these surfaces 16, 19a, 19b, 23-25 are protected and, thus, precluded from contacting the dug material, and as such the surfaces are not sacrificial. Even if some or all of these surfaces 16, 19a, 19b, 23-25 are not sacrificial, as explained, they have compressive residual stresses introduced for increasing a service life of the ground engaging tool.

[0115] Figure 5 shows a wear assembly 100 comprising a wear element 40, an intermediate wear element 30 and a nose 15 of, e.g., another wear element, wherein at least one surface has been mechanically improved in accordance with some embodiments.

[0116] Each of the wear elements 40, 30 illustrated has a body adapted for coupling with at least one other wear element 30, 40. In this sense, a tooth wear element 40 is couplable with the intermediate wear element 30, e.g., an intermediate adapter, and the intermediate wear element 30 is couplable with the tooth wear element 40 and a nose 15 that, in some cases, is part of another wear element such as, e.g., a cast lip.

[0117] The intermediate wear element 30 includes a nose 31 protruding from a main body of the wear element 30 and a cavity (not seen) at a rear end 33 thereof. The nose 31 is adapted for engaging a cavity (not seen) of the tooth wear element 40 at a rear end 42 thereof. The intermediate wear element 30 also includes one or more cavities 32 for receiving a fixing device (e.g., a fixing pin) that secures the attachment of the intermediate wear element 30 to the tooth wear element 40. The cavity at the rear end 33 is adapted for engaging the nose 15. The intermediate wear element may also include one or more holes 34 for receiving a fixing device (e.g., a fixing pin) that secures the attachment of the intermediate wear element 30 to the nose 15.

[0118] One or more surfaces 16 at an interface between the main body and the nose 31 of the intermediate wear element 30 may be mechanically improved as described in the present disclosure. Additionally or alternatively, a surface 18 and / or a surface 35 on a perimeter of the one or more holes 32, 34 respectively is a surface that may be mechanically improved as described in the present disclosure. These surfaces 16, 18, 35 are not wear surfaces.

[0119] A surface 35 adjacent to where cavities 34, 43 for fixing devices are formed may additionally or alternatively be treated for introduction of compressive residual stresses. The surface 35 is free of weld seams.

[0120] The tooth wear element 40 has a main body with a tapered geometry. A ground engaging end 41 at the front of the main body is narrower to ease penetration of the wear element 40 into the engaged material. The main body may include one or more holes 43 for receiving a fixing device (e.g., a fixing pin) in each respective hole to reliably keep attach the two wear elements 30, 40 when engaged. Additionally or alternatively, a surface 35 of a perimeter of the one or more holes 43 respectively is a surface that may be mechanically improved as described in the present disclosure.

[0121] One or more surfaces (not seen) at a rear end 42 of the main body of the tooth wear element 40 may be mechanically improved as described in the present disclosure as these surfaces are exposed to mechanical hits with surfaces on the intermediate wear element 30 during operation of the earth moving machine. Accordingly, such surfaces are subject to large wearing and may suffer the initial formation of cracks.

[0122] The nose 15 may have one or more surfaces 16, 18 mechanically improved as described, for example, with reference to the cast lip 10 of Figures 2A-2B, 3A-3B and 4.

[0123] Figures 6A and 6B show different view perspectives of an intermediate wear element 30 mechanically improved in accordance with some embodiments. Figure 6A shows the intermediate wear element 30 from a top perspective, and Figure 6B shows the intermediate wear element 30 from a bottom perspective.

[0124] The intermediate wear element 30 is similar to that illustrated in the wear assembly of Figure 5. In this example, the nose 31 of the wear element 30 further includes a central rib that alters the interface surface 16 between the protruding nose 31 and the main body of the wear element 30. The treated surface 16 may be at one or both lateral sides, and / or at the top (as best seen in Figure 6A), or the bottom (as best seen in Figure 6B), or both top and bottom sides, like in the embodiments of Figures 6A and 6B.

[0125] Figure 7 shows another example of a wear assembly 110 comprising a wear element 40 and a plate lip adapter 50 mechanically improved in accordance with some embodiments.

[0126] The wear element 40 is, for example, like the wear element 40 described with reference to the wear assembly 100 of Figure 5.

[0127] The plate lip adapter 50a comprises a main body 53a that is C-shaped so as to surround a portion of a blade of digging implements, thereby protecting surfaces of the blade. A nose 51a protrudes from the main body according to a protruding direction. The nose 51a is adapted for engaging the tooth wear element 40 by insertion of the nose 51a into a cavity of the wear element 40.

[0128] The nose 51a includes one or more holes for insertion of a respective fixing device (e.g., a fixing pin). The surface 16 at a top interface and / or a bottom interface between the nose 51a and the main body may be mechanically improved as described in the present disclosure. Additionally or alternatively, a surface 18 of a perimeter of the one or more holes 52a is a surface that may be mechanically improved as described in the present disclosure.

[0129] Figure 8 shows another example of a wear assembly 120 comprising a wear element 50b and a whisler lip 70 mechanically improved in accordance with some embodiments.

[0130] The whisler lip 70 is coupled with digging implements of an earth moving machine at a rear end 76 of the whisler lip 70. The whisler lip 70 is adapted to have one or more wear elements coupled therewith at a front end 75. The whisler lip 70 has a main body, a plurality of contact projections 73 and a plurality of noses 71 protruding from the contact projections 73 and which, owing to the stabilizing capabilities thereof, especially for lateral stabilization, may also be referred to as stabilizing noses 71. The wear element (adapter) 50b is adapted for engaging the whisler lip 70 by insertion of a cavity (not shown) into the stabilizing noses 71.

[0131] One or more lateral surfaces 72 on the stabilizing noses 71 may be mechanically improved. Additionally or alternatively, another radial surfaces 74 of the one or more contact projections 73 of the whisler lip 70 are surfaces that may be mechanically improved as described in the present disclosure.

[0132] Figure 9 shows a section of the wear element 50b (e.g., adapter) assembled on a whisler lip 70. The cavity 54b of the wear element 50b is coupled with the nose 71 of the whisler lip 70. There is some gap 90 between the cavity 54b of the adapter 50b and the stabilizing nose 71 of the whisler lip 70 while there is contact between the contact projections 73 of the whisler lip 70 and the cavity 54b of the adapter 50b.

[0133] It will be noted that shadowed surfaces, such as surfaces 16, 18, 19a, 19b, 23, 24, 25, 35, 72, 74, corresponding to some surfaces that may be improved according to the present disclosure, do not necessarily have to cover entirely the shadowed areas as shown in the Figures or may cover further areas as those shown in the Figures. Different areas on such surfaces are also possible within the scope of the present disclosure, including larges surfaces, smaller surfaces, and differently shaped surfaces, including non-continuous surfaces (namely, there is a non-treated surface between two treated surfaces falling in the same region). Also, and as it can be observed from the shadowed surfaces 16, 18, 19a, 19b, 23, 24, 25, 35, 72, 74 illustrated in the Figures, in the context of the present disclosure, the terms “perimeter” and “interface” do not mean just a line or curve that define the perimeter of, e.g., a hole, or an interface between two different surfaces, but rather these terms are to be understood as encompassing the line or curve and an area adjacent thereto, such as, for example but without limitation, an area at least extending 5 cm or less on one or both sides of the respective perimeter or interface.

[0134] Examples

[0135] Improvement attained by devices, machines and methods according to some examples of the present disclosure has been tested and checked by performing a fatigue resistance test according to EN 6072:2010 Annex D. A set of reference specimens (Reference Specimens 1 to 3) with no introduction of compressive residual stresses with a compressive contact treatment has been used for comparison with a set of treated specimens (Treated Specimens 1 to 3) that have had compressive residual stresses introduced with a compressive contact treatment.

[0136] The following tables show the number of cycles that each specimen has been capable of withstanding in the test prior to breaking.

[0137] The smallest improvement attained corresponding to the ratio of the Treated Specimen with the least number of cycles divided by the Reference Specimen with the greatest number of cycles is over 34%, whereas the greatest improvement attained corresponding to the ratio of the Treated Specimen with the greatest number of cycles divided by the Reference Specimen with the least number of cycles is over 155%.

[0138] Also, further tests for determining how devices, machines and methods, according to some examples of the present disclosure, are improved have been conducted according to LINE-EN ISO 6507-1 :2018. A set of reference specimens (Reference Specimens 4 and 5) with no introduction of compressive residual stresses with a compressive contact treatment has been used for comparison with a set of treated specimens (Treated Specimens 4 and 5) that have had compressive residual stresses introduced with a compressive contact treatment.

[0139] The following tables show an average value of hardness Vickers, i.e., microhardness, for a set of hardness values measured at different depths of the surface from 0.5 mm to 5.0 mm.

[0140] The smallest improvement attained corresponding to the ratio of the Treated Specimen with the lowest average hardness divided by the Reference Specimen with the greatest average hardness is over 12%, whereas the greatest improvement attained corresponding to the ratio of the Treated Specimen with the greatest average hardness divided by the Reference Specimen with the lowest average hardness is over 19%.

[0141] In the context of the present disclosure, all ranges disclosed also include the endpoints thereof.

[0142] In this text, the term “includes”, “comprises” and derivations thereof (such as “including”, “comprising”, etc.) should not be understood in an excluding sense, that is, these terms should not be interpreted as excluding the possibility that what is described and defined may include further elements, steps, etc.

[0143] On the other hand, the disclosure is obviously not limited to the specific embodiment(s) described herein, but also encompasses any variations that may be considered by any person skilled in the art (for example, as regards the choice of materials, dimensions, components, configuration, etc.), within the general scope of the invention as defined in the claims.

Claims

CLAIMS1 . A wear element (10, 30, 40, 50a, 50b, 70) for an earth moving machine, comprising a body (1 , 13, 53) adapted for coupling with at least another wear element; wherein only a portion of at least one surface (2, 16, 18, 19a, 19b, 23, 24, 25, 35, 72, 74) of the body has compressive residual stresses introduced therein; wherein the at least one surface is free of weld seams.

2. The wear element (10, 30, 40, 50a, 50b, 70) of claim 1 , wherein the body (1 , 13, 53) comprises at least one nose (15).

3. The wear element (10, 30, 40, 50a, 50b, 70) of claim 2, wherein the at least one surface (2, 16, 18, 19a, 19b, 23, 24, 25, 35, 72, 74) comprises: a perimeter (18) defining a cavity (17) for receiving a locking pin for coupling another wear element to the wear element; and / or an interface (16) of the body (1 , 13, 53) from which the at least one nose (15) protrudes.

4. The wear element (10, 30, 40, 50a, 50b, 70) of any one of the preceding claims, wherein the body (1 , 13, 53) comprises a cast lip (10).

5. The wear element (10, 30, 40, 50a, 50b, 70) of claim 4, wherein the at least one surface (2, 16, 18, 19a, 19b, 23, 24, 25, 35, 72, 74) comprises at least one cavity (20) between a pair of neighboring noses (15) protruding from the body (1 , 13), the at least one surface optionally comprising: at least one interface (23) between the cavity and a nose of the pair of neighboring noses; and / or at least one edge (24) at an end of the cavity along a direction of protrusion of the pair of neighboring noses.

6. The wear element (10, 30, 40, 50a, 50b, 70) of any one of claims 4-5, wherein the at least one surface (2, 16, 18, 19a, 19b, 23, 24, 25, 35, 72, 74) comprises an interface (19a, 19b) between at least one lateral wall (14) of the body (1) and a portion of the body (1 , 13) from which at least one lateral wall protrudes.

7. The wear element (10, 30, 40, 50a, 50b, 70) of claim 1 , wherein the body (1) comprisesa plate lip (50a), an adapter, an intermediate adapter (40), a tooth bar, a shroud, a cutterhead or a cast corner.

8. The wear element (10, 30, 40, 50a, 50b, 70) of any one of the preceding claims, wherein the compressive residual stresses of the body (1 , 13, 53) are introduced by a compressive contact treatment on the at least one surface (2, 16, 18, 19a, 19b, 23, 24, 25, 35, 72, 74).

9. The wear element (10, 30, 40, 50a, 50b, 70) of any one of the preceding claims, wherein a strength of the compressive residual stresses in the at least one surface (2, 16, 18, 19a, 19b, 23, 24, 25, 35, 72, 74) is greater than or equal to 0.80 times: a yield strength of the at least one surface prior to introduction of the compressive residual stresses therein; and / or a yield strength of a portion of the body not including the at least one surface.

10. The wear element (10, 30, 40, 50a, 50b, 70) of any one of the preceding claims, wherein a hardness of the at least one surface (2, 16, 18, 19a, 19b, 23, 24, 25, 35, 72, 74) is at least 10% greater than: a hardness of the at least one surface prior to introduction of the compressive residual stresses therein; and / or a hardness of a portion of the body not including the at least one surface.11 . The wear element (10, 30, 40, 50a, 50b, 70) of any one of the preceding claims, wherein the body (1 , 13, 53) is adapted to engage ground or material during operation of the earth moving machine.

12. The wear element (10, 30, 40, 50a, 50b, 70) of any one of the preceding claims, wherein at least one surface (2, 16, 18, 19a, 19b, 23, 24, 25, 35, 72, 74) is not a wear surface.

13. The wear element (10, 30, 40, 50a, 50b, 70) of any one of the preceding claims, wherein the at least one surface comprises at least one edge and / or at least one interface.

14. A wear assembly comprising at least one wear element (10, 30, 40, 50a, 50b, 70) according to any one of preceding claims, wherein the wear assembly preferably is or comprises digging implements.

15. A method for treating at least one wear element (10, 30, 40, 50a, 50b, 70) for an earthmoving machine, comprising applying a compressive contact treatment to the at least one wear element whereby a tool contacts only a portion of at least one surface (2, 16, 18, 19a, 19b, 23, 24, 25, 35, 72, 74) of the at least one wear element for introducing compressive residual stresses therein, wherein each wear element of the at least one wear element comprises a body (1 , 13, 53) adapted for coupling with at least another wear element; and wherein the at least one surface is free of weld seams.

16. A method for manufacturing at least one wear element (10, 30, 40, 50a, 50b, 70) for an earth moving machine, comprising: manufacturing the at least one wear element, the manufacturing optionally comprising casting or forging; and applying a compressive contact treatment to the at least one manufactured wear element whereby a tool contacts only a portion of at least one surface (2, 16, 18, 19a, 19b, 23, 24, 25, 35, 72, 74) of the at least one wear element for introducing compressive residual stresses therein, wherein each wear element of the at least one wear element comprises a body (1 , 13, 53) adapted for coupling with at least another wear element; wherein the at least one surface is free of weld seams.

17. The method of any one of claims 15-16, wherein applying the compressive contact treatment comprises: a first application of the compressive contact treatment whereby the tool has a first peening intensity; and a second application of the compressive contact treatment whereby the tool has a second peening intensity; wherein the second application is posterior to the first application, and wherein the first peening intensity is greater than the second peening intensity.

18. The method of claim 17, wherein the first peening intensity is between 3 and 5 times greater than the second peening intensity.

19. The method of any one of claims 15-18, wherein the body (1 , 13, 53) is adapted to engage ground or material during operation of the earth moving machine.

20. The method of any one of claims 15-19, wherein at least one surface (2, 16, 18, 19a, 19b, 23, 24, 25, 35, 72, 74) is not a wear surface.

21. The method of any one of claims 15-20, wherein the at least one surface comprises at least one edge and / or at least one interface.

Images