Patent Application
20230150592
The present disclosure relates generally to an idler in an undercarriage system of a track-type machine, and more particularly to one-piece replaceable idler wear pads for extending idler service life.
Track-type machines are used throughout the world in a great many different off-highway applications. In a typical configuration each of two ground-engaging tracks in a machine includes an endless loop of track links in two parallel track chains extending about rotating elements including one or more idlers and a drive sprocket. Track shoes, commonly equipped with grousers, are attached to the track chains and contact a substrate to propel and steer the machine. In rough, uneven, rocky, steep, and slippery field service environments track-type machines are indispensable for many activities.
Due to the nature of substrate materials and service conditions, wear between and among components in an undercarriage system of a track-type machine can be relatively severe. In view of the wear phenomena, and the necessity for generally robust and sophisticated track and undercarriage construction, inspection, servicing, and replacement of undercarriage parts is routine. As noted above, one or more idlers are typically provided which rotate passively in contact with the track as the track advances during service. The idler is commonly arranged to rotate in contact with track rails formed by the parallel chains of track links. Over the course of time material of the contacting components tends to be worn away, eventually requiring replacement of the idler.
Various proposals are known for reuse, repair, and otherwise extending idler service life. In commonly owned U.S. Pat. No. 8,770,672 to Yelistratov, an undercarriage system includes an idler having a compound annular rim capping a hub and formed of a relatively higher hardness metallic material. The use of relatively higher hardness metallic material apparently is intended to extend idler service life, and the disclosed techniques can enable replacement of worn-away material in a used idler, for example. While Yelistratov may have various applications and advantages, there is always room for improvement and development of alternative strategies.
In one aspect, an idler for an undercarriage system in a track-type machine includes an idler rim having an outer rim surface extending circumferentially around an idler access of rotation and forming a radially projecting central guide flange. The idler further includes a plurality of one-piece wear pads attached to the idler rim upon a first axial side of the radially projecting central guide flange and upon a second axial side of the radially projecting central guide flange. Each of the plurality of one-piece wear pads includes a sacrificial head supported on the outer rim surface and having an outer link-contact surface, and a base in interlocking engagement with the idler rim.
In another aspect, an idler for an undercarriage system in a track-type machine includes an idler rim having an outer rim surface extending circumferentially around an idler axis of rotation, and an inner surface forming a shaft bore extending between a first axial idler side and a second axial idler side. The first axial idler side includes a first axial end face extending radially inward from the outer rim surface, and the second axial idler side includes a second axial end face extending radially inward from the outer rim surface. The idler rim further includes a plurality of pad retention channels arranged in a first set extending radially inward from the outer rim surface and axially inward from the first axial end face, and a second set extending radially inward from the outer rim surface and axially inward from the second axial end face.
In still another aspect, an idler wear pad for an idler in an undercarriage system includes a one-piece pad body having an elongate sacrificial head including an inner idler-contact surface, and an outer link-contact surface extending fore and aft between a first head end and a second head end and having an arcuate longitudinal profile that is upwardly convex. The one-piece pad body further includes a neck attached to the elongate sacrificial head longitudinally between the first head end and the second head end and extending downwardly from the inner idler-contact surface, and a base extending outwardly from the neck both fore and aft to interlock the one-piece pad body within a pad retention channel in an idler.
Referring to
Referring also now to
Idler 30 further includes a plurality of one-piece wear pads 62 attached to idler rim 34 upon a first axial side of radially projecting central guide flange 40 and upon a second axial side of radially projecting central guide flange 40. One-piece wear pads 62 may each include a forging, a casting, a cut segment of an elongate, shaped forging, for example, or any other suitable body made of a suitable metallic material. Wear pads 62 might also be heat treated or hardened by another process in some embodiments. The metallic material of wear pads 62 may be the same as the material of which idler rim 34 is made, or different. In some embodiments wear pads 62 may include or be formed entirely from a relatively harder material than idler rim 34. Each of the plurality of wear pads 62 includes a sacrificial head 64 supported on outer rim surface 36 and having an outer link-contact surface 66, and a base 68 in interlocking engagement with idler rim 34. Sacrificial head 64 may be elongate in a direction circumferentially around idle axis of rotation 38. The term “sacrificial” is used in reference to expected and intended wearing away of material of wear pads 62 during service, as further discussed herein.
Also shown in
With focus on
As noted above, wear pads 62 each include a base 68 in interlocking engagement with idler rim 34. It is contemplated that a variety of different geometries of wear pads 62 and pad retention channels 60 could provide interlocking to secure wear pads 62 upon idler rim 34. Polygonal shapes of the respective bases and pad retention channels, non-polygonal shapes, L-shapes, T-shapes as shown, or still another could be employed. In a typical construction wear pads 62 are interlocking with idler rim 34 but removable. Thus, when it is desirable to replace wear pads 62, the used wear pads 62 can be slid out of pad retention channels 60 in axially outward directions and swapped out for new wear pads.
In the illustrated embodiment idler 30 further includes a first pad retainer 112 attached to first axial end face 56 and a second pad retainer 114 attached to second axial end face 58, each clamping or otherwise retaining a plurality of wear pads 62 within a plurality of pad retention channels 60. Also in the illustrated embodiment first pad retainer 112 and second pad retainer 114 are bolted to the respective first and second axial end face 56 and 58 by way of bolts 116. Other attachment strategies for wear pads 62 and/or pad retainers 112 and 114 could be used. For instance, wear pads 62 could be interference-fitted or spot welded. Analogously, pad retainers 112 and 114 could be bolted at locations radially inward from those shown, interference-fitted, or welded. Still other attachment strategies, including reversible and non-reversible attachment strategies, could be employed. A non-reversible attachment strategy would include a mechanism for attachment, which to overcome and decouple the parts, would require cutting or modifying components such that they are not reusable, at least without modification. As depicted in the drawings each of first pad retainer 112 and second pad retainer 114 may include one retaining ring. In other instances, arc segments of a ring, plates, covers, or another structure altogether could be used.
Referring also now to
Idler wear pad 62 and one-piece pad body 86, referred to at times interchangeably herein, further includes a neck 98 attached to sacrificial head 64 longitudinally between first head end 90 and second head end 94 and extending downwardly from inner idler-contact surface 88. Base 68 may extend outwardly from neck 98 both fore and aft to interlock idler wear pad 62 within a pad retention channel 60 in idler 30. When interlocked with idler rim 34, neck 98 and base 68 may be entirely within idler rim 34, mostly or entirely axially inward of the respective axial end face 56 and 58. Sacrificial head 64 may likewise be mostly or entirely axially inward of the respective axial end face 56 and 58, and radially outward of outer rim surface 36. Sacrificial head 64 may be elongate in the fore and aft direction. When installed for service on idler rim 34 wear pads 62 may be arranged end-to-end upon the first axial side of central guide flange 40 and upon the second axial side of central guide flange 40. A number of wear pads 62 may be 8 or greater in some embodiments, and in a refinement greater than 12. Sacrificial head 64, neck 98, and base 68, together form a first planar side face 100 and a second planar side face 102 opposite to first planar side face 100, of one-piece pad body 86. A pad thickness dimension 104 is defined between first planar side face 100 and second planar side face 102. A head height dimension 106 that is equal to or less than pad thickness dimension 104 is defined between base 68 and inner idler-contact surface 88. Base 68 may include a forward projecting retention edge 108 and a rearward projecting retention edge 110, structured to fit into forward recess 82 and rearward recess 84, respectively. It can also be seen from the drawings, and
Referring to the drawings generally, during service idler 30 will rotate with the advancement of track 20 in forward directions or reverse directions about the various track contacting rotatable elements in undercarriage system 12. Wear pads 62 will rotate in contact with track rail 26 and the track rail hidden from view in the illustration of
The present description is for illustrative purposes only, and should not be construed to narrow the breadth of the present disclosure in any way. Thus, those skilled in the art will appreciate that various modifications might be made to the presently disclosed embodiments without departing from the kill and fair scope and spirit of the present disclosure. Other aspects, features and advantages will be apparent upon an examination of the attached drawings and appended claims. As used herein, the articles “a” and “an” are intended to include one or more items, and may be used interchangeably with “one or more.” Where only one item is intended, the term “one” or similar language is used. Also, as used herein, the terms “has,” “have,” “having,” or the like are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise.
