US20150129265A1

US20150129265A1 - Wear assembly

Info

Publication number: US20150129265A1
Application number: US14/596,243
Authority: US
Inventors: Bruce R. Vahling
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2015-01-14
Filing date: 2015-01-14
Publication date: 2015-05-14

Abstract

A wear assembly positioned between contacting surfaces a moldboard assembly and at least one of a mounting bracket or a work implement of a work machine. The wear assembly includes a plurality of wear strips having a first surface and a second surface defining a thickness of the wear strip therebetween. The first surface of the wear strip is positioned in a contacting relationship with one of the contacting surfaces, and the second surface of the wear strip is positioned in a contacting relationship with an other of the contacting surfaces. At least one of the first or second surfaces of each of the plurality of wear strips includes a number of recesses infused with a lubricant, such that the number of recesses is formed on a surface area of the wear strip in frictional contact with at least one of the contacting surfaces.

Description

TECHNICAL FIELD

The present disclosure relates to a wear assembly, and more particularly towards the wear assembly associated with contacting surfaces of a work implement of a machine.

BACKGROUND

Machines, for example motor graders, are commonly used in earth leveling applications, such as, road maintenance or surface contouring. Motor graders typically have a steerable front frame and a driven rear frame connected to the front frame by an articulation joint. The front frame supports a movable drawbar-circle-moldboard (DCM) that holds a work implement used to perform the leveling operations. The DCM is suspended from a main beam of the front frame and has a yoke extending forward and pivotally connected to the front frame. Movement of the DCM relative to the front frame results in a corresponding movement of the work implement.
The work implement, typically a blade, is connected to a circle member of the DCM. The circle member is positioned relative to the yoke by way of shoes that allow relative rotation between the circle member and the yoke, but inhibit relative translation. During operation, the blade is exposed to significant forces and vibrations. In order to reduce wear of the circle member and the yoke caused by operation, wear inserts made of a relatively softer sacrificial material may be placed between the shoes and the circle member and between the circle member and the yoke. However, such wear inserts may have limited life of operation in view of their limited capacity of providing a frictionless operation among the contacting surfaces that rub against each other during operation.
U.S. Pat. No. 7,673,699, hereinafter referred to as '699 patent, relates to sway restrictor bracket for a draft link of a three point hitch. A plurality of wear pads is disposed on a plurality of contacting surfaces of components of a machine. Suitable materials of construction of wear pads can include, but are not limited to, well known, commercially available glass filled plastics, lubricant impregnated metallic materials, and sintered materials. The adjustability of the wear pads allows compensating for wear as it occurs during operation of the machine. However, '699 patent does not does not disclose any functional or structural solution for extending the life of the wear pads against frictional forces as described in the present disclosure.

SUMMARY OF THE DISCLOSURE

In one aspect of the present disclosure, a wear assembly for a work machine is disclosed. The wear assembly positioned between contacting surfaces a moldboard assembly and at least one of a mounting bracket or a work implement of the work machine. The wear assembly includes a plurality of wear strips having a first surface and a second surface defining a thickness of the wear strip therebetween. The first surface of the wear strip is positioned in a contacting relationship with one of the contacting surfaces, and the second surface of the wear strip is positioned in a contacting relationship with an other of the contacting surfaces. At least one of the first or second surfaces of each of the plurality of wear strips includes a number of recesses infused with a lubricant, such that the number of recesses is formed on a surface area of the wear strip in frictional contact with at least one of the contacting surfaces.
Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an exemplary machine, according to one embodiment of the present disclosure;

FIG. 2 is an exploded perspective view of a drawbar-circle-moldboard (DCM) assembly associated with the machine of FIG. 1, according to one embodiment of the present disclosure;

FIG. 3 is a perspective view of an exemplary wear strip used in association with the DCM assembly of FIG. 2, according to one embodiment of the present disclosure;

FIG. 4 is a top perspective view of a yoke plate of the DCM assembly of FIG. 2 and an enlarged perspective view of a portion of the upper yoke surface showing the wear assemblies, according to one embodiment of the present disclosure;

FIG. 5 is a perspective view of another wear strip used in the yoke plate of FIG. 4, according to one embodiment of the present disclosure;

FIG. 6 is a bottom perspective view of a portion of the drawbar-circle-moldboard (DCM) assembly of FIG. 2, according to one embodiment of the present disclosure; and

FIG. 7 is a perspective view of a circle shoe of the drawbar-circle-moldboard (DCM) assembly of FIG. 6 with yet another wear strip, according to one embodiment of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to specific aspects or features, examples of which are illustrated in the accompanying drawings. Wherever possible, corresponding or similar reference numbers will be used throughout the drawings to refer to the same or corresponding parts.
FIG. 1 shows a side view of a motor grader, hereinafter work machine 100, according to an aspect of the current disclosure. The work machine 100 is used to level a surface of the ground. The work machine 100 includes a frame. The frame includes a front frame 102 and a rear frame 104 coupled with the front frame 102. The front frame 102 is pivotally coupled with the rear frame 104 such that the front frame 102 can rotate relative to the rear frame 104. In another aspect of the current disclosure, the work machine 100 may include a single frame. The front frame 102 and the rear frame 104 are supported on ground engaging members 107. The front frame 102 includes a beam 105 having a front end 111 coupled with the ground engaging members 107 and a rear end 109 pivotally coupled with the rear frame 104. In another aspect of the current disclosure, the ground engaging members 107 coupled with the front frame 102 may include an axle having both ends rotatably coupled with wheels. Similarly, the ground engaging members 107 coupled with the rear frame 104 may include one or more axles having both ends rotatably coupled with wheels. Alternatively, the ground engaging members 107 may be tracks.
The work machine 100 further includes an implement 106 for performing various earth moving operations, such as ground levelling. The implement 106 is disposed in the front frame 102. Specifically, the implement 106 is supported on the beam 105. The implement 106 includes a blade 108 arranged to be in contact with a surface of the ground. The work machine 100 further includes a power source (not shown) to supply power to various components including, but not limited to, the ground engaging members 107 and the implement 106. In another aspect of the current disclosure, the power source may be an engine. The engine is disposed in the rear frame 104. In another embodiment, the power source may include a battery, a fuel cell or any other electrical power storage device known in the art. The engine drives the ground engaging members 107 via a transmission (not shown). The transmission may produce multiple output speed ratios or a continuously variable speed ratio between the engine and the ground engaging members 107. Further, an operator cab 110 is supported on the front frame 102. The operator cab 110 includes various operator controls, along with displays or indicators used to drive the work machine 100 and convey information to an operator.
FIG. 2 illustrates a drawbar-circle-moldboard (DCM) assembly 200 associated with the work machine 100. The DCM assembly 200 includes a yoke 202 that rotatably supports a circle assembly 204, and a hydraulic ram assembly 206 that connects the implement 106 to the circle assembly 204. The implement 106 includes the blade 108, or may alternatively include a ripper, or any other implement known in the art. The hydraulic ram assembly 206 shifts the implement 106 side-to-side relative to the DCM assembly 200, and rotates the implement 106 about a horizontal axis A-A′ that is generally orthogonal to a vertical mid-plane of the work machine 100 (referring to FIG. 1).
The yoke 202 includes a pair of draw bars 208 positioned in a general V-shape or Y-shape and connected at a tip end 210 and at an opposing wider end 212 to a crossbar 214. The draw bars 208 and the crossbar 214, at the wider end 212, are positioned on and mounted to a yoke plate 216 having an upper yoke surface 218 and a lower yoke surface 219. A motor (not shown) may also be mounted to the upper yoke surface 218 of the yoke plate 216 and includes a drive gear (not shown) that extends through the yoke plate 216 to mesh with internal teeth 504 (see FIG. 6) of the circle assembly 204, in order to rotate the circle assembly 204 and the implement 106 relative to the yoke 202.
The DCM assembly 200 has a plurality of contacting surfaces due to relative movement between various parts of the DCM assembly 200. The contacting surfaces are surfaces that mate or rub against each other during operation of the work machine 100 and the DCM assembly 200. A wear assembly 130 is provided in association with the contacting surfaces of the DCM assembly 200. The wear assembly 130 includes two wear strips 124 placed between the contacting surfaces. The two wear strips 124 of the wear assembly 130 are described in detail in the foregoing description.
As shown in FIG. 2, the implement 106 includes the blade 108 and blade rails 103 coupled to the blade 108. The blade rails 103 are slidably coupled to a retainer 115. Further, the retainer 115 is pivotally coupled to an arm portion 120 of the circle assembly 204. The blade rails 103 are arranged to be slidably received in jaws 117 of a mounting bracket 122 of the retainer 115. The blade 108 can slide along the axis A-A′ when received into the jaws 117. An outer surface 220 of the blade rails 103 is in frictional contact with an inner surface 222 of the jaws 117, as the blade rails 103 slides in the jaws 117 during operation of the work machine 100. As illustrated, a wear strip 124 is positioned within the jaws 117. The wear strip 124 is positioned between contacting surfaces of the DCM assembly 200, i.e. the wear strip 124 is arranged to contact with the blade rails 103 and the jaws 117 of the DCM assembly 200 when installed. The wear strip 124 is embodied as a U shaped wear strip, and will be explained in detail in connection with FIG. 3.
FIG. 3 illustrates a perspective view of one of the wear strips 124, hereinafter interchangeably referred to as U shaped wear strip 124. The U shaped wear strip 124 is arranged to be received between a first set of contacting surfaces, i.e., the inner surface 222 of the jaws 117 (see FIG. 2) and the outer surface 220 of the blade rails 103 (see FIG. 2) to provide protection against wear and reduce or eliminate friction during sliding movement of the blade 108. The U shaped wear strip 124 has a first surface 302 and a second surface 304. The first surface 302 and the second surface 304 define a thickness T1 of the U shaped wear strip 124. The first surface 302 is arranged to be secured to the inner surface 222 of the jaws 117 (see FIG. 2), and the second surface 304 is configured to be exposed to the outer surface 220 of the blade rails 103 (see FIG. 2). The U shaped wear strip 124 may be fabricated from a material that is softer than a material of the first set of contacting surfaces. For example, the U shaped wear strip 124 may be fabricated from a non-metallic material, such as, glass-filled nylon or from a relatively soft metallic material such as brass or bronze, while the contacting surfaces may be fabricated from steel.
The second surface 304 of the U shaped wear strip 124 includes a number of recesses 306 provided thereon. The recesses 306 are defined by a concave texture, including without limitation, nano-to-micro size pores, holes, dimples, grooves, inverted facets or the like. The recesses 306 are provided on the second surface 304 of the U shaped wear strip 124, using known processes like laser texturing, peening, etching etc. The recesses 306 are structured to be infused with a lubricant 308. The lubricant 308 may be any known solid state lubricant, for example, plastic mixed with graphite, etc. In an embodiment, the lubricant 308 infused into the recesses 306 may reduce or eliminate friction between the first set of contacting surfaces, i.e., the inner surface 222 of the jaws 117 and the outer surface 220 of the blade rails 103. The lubricant 308 may also improve wear and scuffing resistance of the plurality of U shaped wear strip 124.
Referring to FIG. 4, the circle assembly 204 is positioned both axially and radially relative to the yoke 202 by way of a plurality of wear assemblies 402, and by way of a plurality of circle shoes 516, (see FIG. 5). The wear assemblies 402 are annularly distributed around an upper periphery of the yoke 202 to axially push the circle assembly 204 away from the yoke 202 and toward the circle shoes 516 (see FIG. 5), while the circle shoes 516 are annularly distributed around a lower periphery of the yoke 202 to bias the circle assembly 204 upward toward the yoke 202. In this manner, the circle assembly 204 is effectively sandwiched between the wear assemblies 402 and the circle shoes 516 (see FIG. 5) and thereby axially retained in a desired position relative to the yoke 202. The circle shoes 516 includes geometry structured to radially position the circle assembly 204 relative to the yoke 202 when the circle assembly 204 is biased toward the circle shoes 516 (see FIG. 5) by the wear assemblies 402.
As shown in FIG. 4, the yoke plate 216 embodies a mounting component configured to receive the wear assemblies 402. Specifically, each of the wear assemblies 402 are associated with a channel 404 in the yoke plate 216 passing from the upper yoke surface 218 through the lower yoke surface 219. The wear assemblies 402 include a plurality of wear strips 406, hereinafter interchangeably referred to as arcuate wear strip 406, a biasing assembly 408, and a cover 410. The arcuate wear strip 406 and the biasing assembly 408 are disposed within the channel 404. Further, the cover 410 is placed to close the channel 404.
FIG. 5 illustrates a perspective view of the arcuate wear strip 406. The arcuate wear strip 406 embodies a substrate having a first surface 412 and a second surface 414. The arc contour (not shown) of the arcuate wear strip 406 substantially matches the outer shape of a circle assembly 204 (i.e., an outer radius (not shown) of the arcuate wear strip 406 may be about equal to or less than the outer radius (not shown) of the circle assembly 204). The first surface 412 and the second surface 414 define a thickness T2 of the arcuate wear strip 406. In an embodiment, the second surface 414 includes a number of recesses 416 infused with the lubricant 418 similar to the recesses 306 and the lubricant 308 respectively described earlier. The arcuate wear strip 406 may be fabricated of a material similar to the plurality of U shaped wear strips 124 as mentioned earlier.
Referring to FIG. 4, the arcuate wear strip 406 is located within a bottom of the channel 404 to ride against an upper surface of the circle assembly 204. The arcuate wear strip 406 is provided between contacting surfaces of the DCM assembly 200, i.e., the lower surface 219 of the yoke plate 216 and the upper surface (not shown) of the circle assembly 204. In this manner, the second surface 414 of the arcuate wear strip 406 is utilized as a cushioning layer that may reduce damage caused to the lower surface 219 of the yoke plate 216 and/or the upper surface of the circle assembly 204 during operation. FIG. 6 illustrates a bottom perspective view of a portion of the DCM assembly 200. The circle assembly 204 includes a circle member 502 having the internal teeth 504 in the form of an integral ring gear, having a lower surface 508, and a rim 510 protruding from lower surface 508 away from the yoke 202. The rim 510 includes an inner annular surface 512.
The circle shoe 516 includes a base portion 518 that may be welded to the yoke plate 216, and an associated lip portion 520 separate from and bolted to base portion 518. The lip portion 520 additionally includes a hinge portion 522 configured to loosely engage, at a joint 524, a hinge base 526 that may also be welded to the yoke plate 216. The loose engagement at the joint 524, in conjunction with the oversized holes or slots 515 (see FIG. 7) may provide for an initial radial adjustment of the lip portion 520 via one or more adjustment screws 527. It is contemplated that base portion 518 and/or the hinge base 526 may alternatively be an integral component and/or connected to the yoke plate 216 in a manner other than welding, if desired. The distal end of the lip portion 520 is provided with a wear assembly 525 that include a wear strip 528 hereinafter interchangeably referred to as a circle shoe wear strip 528.
FIG. 7 illustrates a perspective view of the circle shoe 516 with the circle shoe wear strip 528. In an example, the circle shoe wear strip 528 is a right angled shaped wear strip secured to a top surface 530 and a side surface 532, of the lip portion 520 of the circle shoe 516. During operation of the DCM assembly 200, the top surface 530 remains in frictional contact with the lower surface 508 of the ring gear 504, and the side surface 532 remains in frictional contact with the inner annular surface 512 of the rim 510. In context of the present disclosure, the top surface 530, the lower surface 508 and the side surface 532 and the inner annular surface 512 constitute contacting surfaces, and may be prone to damage due to frictional wear and tear during operation of the work machine 100.
The circle shoe wear strip 528 includes a first surface 602 and a second surface 604. The circle shoe wear strip 528 is so disposed on the circle shoe 516 so as to act as a cushioning layer between the top surface 530, the lower surface 508 of the internal teeth 504, the side surface 532 of the circle shoe 516, and the inner annular surface 512 of the rim 510, such that wear and tear between the contacting surfaces may be reduced. The first surface 602 and the second surface 604 define a thickness T3 of the circle shoe wear strip 528. In an embodiment, the second surface 604 includes a number of recesses 606 infused with a lubricant 608 similar to the recesses 306 and the lubricant 308 respectively as described earlier. The circle shoe wear strip 528 may be fabricated of a material similar to the plurality of U shaped wear strips 124 as mentioned earlier.

INDUSTRIAL APPLICABILITY

The industrial applicability of the wear assembly 130, 402, 525 described herein will be readily appreciated from the foregoing discussion. The wear assembly 130, 402, 525 includes the plurality of wear strips 124, 406, and 528 respectively configured to be received between the plurality of contacting surfaces i.e., the outer surface 220 of the blade rails 103 and the inner surface 222 of the jaws 117; the lower surface 219 of the yoke plate 216 and the upper surface (not shown) of the circle assembly 204; the top surface 530 of the circle shoe 516 and the lower surface 508 of the internal teeth 504; and the side surface 532 of the circle shoe 516 and the inner annular surface 512 of the rim 510 as described earlier. The plurality of wear strips 124, 406, and 528 may safeguard the above given surfaces against wear and tear, during relative movement of these surfaces. The wear assembly 130, 402, 525 may be used with any machine having a drawbar-circle-moldboard (DCM) to axially and radially position the DCM.
The plurality of wear strips 124, 406, 528 further include the number of recesses 306, 416, 606 infused with the lubricant 308, 418, 608 respectively which provides enhanced lubrication among the plurality of contacting surfaces. The number of recesses 306, 416, 606 infused with the lubricant 308, 418, 608 respectively may also increase wear and scuffing resistance of the wear strips 124, 406, 528. This provides durability to the wear strips 124, 406, 528 against erosion and breakage, and may increase the life cycle of the wear strips 124, 406, 528. The wear assembly 130, 402, 525 have a simple, low-cost structure for improving lubrication and wear resistance of the DCM assembly 200 during operation of the work machine 100.
While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.

Claims

What is claimed is:

1. A wear assembly associated with a moldboard assembly of a work machine, the wear assembly being positioned between contacting surfaces of the moldboard assembly and at least one of a mounting bracket or a work implement of the work machine, the wear assembly comprising:

a plurality of wear strips positioned between the contacting surfaces, the contacting surfaces configured to move relative to each other, each of the plurality of wear strips having a first surface and a second surface, the first and second surfaces defining a thickness of the wear strip therebetween,

wherein the first surface of the wear strip is positioned in a contacting relationship with one of the contacting surfaces, wherein the second surface of the wear strip is positioned in a contacting relationship with an other of the contacting surfaces, and

wherein at least one of the first or second surfaces of each of the plurality of wear strips includes a number of recesses formed thereon, each of the number of recesses configured to be infused with a lubricant therein, such that the number of recesses are formed on a surface area of the wear strip in frictional contact with at least one of the contacting surfaces.