Technical Field

This invention relates generally to a pin joint, and more particularly to a pin joint for a machine.

Background

Machines with earth moving or material handling capabilities, such as wheel loaders, track loaders, backhoes and the like, typically include a movable implement attached by a linkage assembly to a frame. Such linkage assemblies include one or more pin joints for allowing pivotal movement between various components. Pivotal joints include a pin and a bearing mounted within bores of the components for supporting pivotal movement.

The bearing and the pin may experience wear during operation. In particular, various interfacing surfaces between the pin and the bearing may experience galling due to adhesion between the surfaces. This may lead to failure of either the bearing or the pin or both at one or more interfacing surfaces. Failed components may be expensive to replace. Further, replacement of the components may also require special tools and be time consuming.

U. S. Patent Number 6,962,458 describes a coupling device for equipment implements. The coupling device does not impair the lubricity of bearing sections when the equipment is in service, does not cause seizure during rotation of bearings, does not need frequent feeding of grease to the bearing sections from outside, and provides good noise absorbability. The structure of the coupling device includes a metal based contact material capable of storing a lubricating oil and/or lubricant is interposed between an implement bushing made from steel and implement pin of an implement for construction equipment.

Summary of the Disclosure

In one aspect of the present disclosure, a pin joint for a machine is provided. The pin joint includes a housing. The pin joint further includes a pin at least partly received within the housing, the pin having an outer surface. The pin joint also includes a bearing member coupled to the housing, the bearing member having an inner surface facing the outer surface of the pin. The pin joint includes an insert member axially retained between the bearing member and the pin, the insert member having an inner surface contacting the outer surface of the pin and an outer surface contacting the inner surface of the bearing member. The inner surface of the insert member is configured to freely rotate relative to the outer surface of the pin and the outer surface of the insert member is configured to freely rotate relative to the inner surface of the bearing member.

In another aspect of the present disclosure, a machine is provided. The machine includes a frame. The machine further includes an implement system coupled to the frame. The implement system includes a first implement member, a second implement member, and a pin joint pivotally coupling the second implement member to the first implement member. The pin joint comprises a first housing connected to the first implement member. The pin joint includes a second housing provided adjacent to the first housing, the second housing being connected to the second implement member. The pin joint also includes a pin at least partly received within the first housing and the second housing, the pin having an outer surface. The pin joint includes a bearing member coupled to the second housing, the bearing member having an inner surface facing the outer surface of the pin. The pin joint further includes an insert member axially retained between the bearing member and the pin, the insert member having an inner surface contacting the outer surface of the pin and an outer surface contacting the inner surface of the bearing member. The inner surface of the insert member is configured to freely rotate relative to the outer surface of the pin and the outer surface of the insert member is configured to freely rotate relative to the inner surface of the bearing member.

In yet another aspect of the present disclosure, a method for assembling a pin joint having a housing is provided. The method includes providing a pin at least partly within the housing. The method further includes press fitting an outer surface of a bearing member to the housing. The method also includes providing an insert member between an inner surface of the bearing member and an outer surface of a pin. The method includes providing a sliding fit between an outer surface of the insert member and an inner surface of the bearing member. The method further includes providing a sliding fit between an inner surface of the insert member and an outer surface of the pin. The method includes axially retaining the insert member between the bearing member and pin.

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 with a pin joint connecting a first implement member to a second implement member, according to an embodiment of the present disclosure;

FIG. 2 is a sectional view of the pin joint, according to an embodiment of the present disclosure;

FIG. 3 is a sectional view of the pin joint, according to yet another embodiment of the present disclosure;

FIG. 4 is a sectional view of the pin joint, according to a further embodiment of the present disclosure;

FIG. 5 is a perspective view of an insert member of the pin joint, according to an embodiment of the present disclosure; and

FIG. 6 is a flowchart illustrating a method for assembling the pin joint, according to an embodiment of the present disclosure.

Detailed Description

Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or the like parts. FIG. 1 represents an exemplary machine 100. In the illustrated embodiment, the machine 100 may be a wheel loader. It should be understood that the machine 100 may alternatively include other machines used in various industries, such as mining, transportation, construction, forestry, agriculture, and the like. Further, the machine 100 may be, for example, but not limited to, an excavator, a back hoe loader, a dozer and the like.

Referring to FIG. 1, the machine 100 may include a chassis and/or a frame 102 with a front portion 104. A powertrain or a drivetrain (not shown) may be provided on the machine 100 for the production and transmission of motive power. The powertrain may include a power source which may be located within an enclosure 106 of the machine 100. The power source may include one or more engines, power plants or other power delivery systems such as batteries, hybrid engines, and the like. It should be noted that the power source may also be external to the machine 100. A set of ground engaging members 108, such as wheels, may also be provided on the machine 100 for the purpose of mobility. The powertrain may further include a torque converter, transmission inclusive of gearing, drive shaft and other known drive links provided between the power source and the set of ground engaging members 108 for the transmission of motive power. Further, the machine 100 includes an operator cabin 110 which may house controls for operating the machine 100.

The machine 100 further includes an implement system 111 coupled to the front portion 104 of the frame 102. The frame 102 includes a first implement member 120 extending from the front portion 104. Further, the first implement member 120 may be a stationary part of the front portion 104 of the frame 102. The first implement member 120 includes spaced flanges 112 (shown in FIG. 2). A pin joint 116 may pivotally connect a second implement member 114, in the form of a lift arm, to the flanges 112 of the first implement member 120. One or more hydraulic or pneumatic cylinders (not shown) may actuate the second implement member 114 relative to the first implement member 120.

Referring to FIG. 1, an implement 124, in the form of a bucket, may be pivotally connected to the second implement member 114 by a pin joint 117. Further, a tilt linkage assembly 126 is connected to the implement 124. The tilt linkage assembly 126 includes a cylinder 128 configured to extend or retract the tilt linkage assembly 126. The tilt linkage assembly 126 may enable the implement 124 to be pivoted relative to the second implement member 114. During an operation of the machine 100, the second implement member 1 14 and the tilt linkage assembly 126 may be moved to different positions in order to perform various tasks, such as excavation, lifting, dumping, and the like.

The implement system 111, as described above, is for illustrative purposes only, and various alternative implement systems including one or more pin joints may be contemplated within the scope of the present disclosure. The implement system 111 may vary based on the type of the machine 100 and the operations to be performed. For example, the implement system 111 may include a dipper, an arm and a boom. The pin joint 116 may enable pivotal movement of the second implement member 114 relative to the first implement member 120. Similarly, the pin joint 117 may enable pivotal movement of the implement 124 relative to the second implement member 114. It may be contemplated that various features of the pin joint 116 may also be implemented in the pin joint 117. Various details of the pin joint 116 will be now described hereinafter.

FIG. 2 illustrates a sectional view of the pin joint 116, according to an embodiment of the present disclosure. The pin joint 116 pivotally connects the second implement member 114, to the spaced flanges 112 of the first implement member 120, about a pivot axis P-P'. Each of the spaced apart fianges 112 may include first housings 201. The first housings 201 may be substantially cylindrical about the pivot axis P-P'. The first housings 201 defines axially aligned bores 202. The second implement member 114 includes a second housing 204. The second housing 204 may be substantially cylindrical about the pivot axis P-P'. The second housing 204 defines an elongate bore 206 axially aligned with the bores 202. In an embodiment, the first housings 201 are stationary and the second housing 204 is pivotal relative to the first housings 201.

The pin joint 116 includes a pin 208 at least partly received within the bores 202 and the elongate bore 206 of the first housings 201 and the second housing 204, respectively. A longitudinal axis of the pin 208 may be aligned with the pivot axis P-P'. The pin 208 has an outer surface 210.

The pin 208 may extend through the bores 202 and the elongate bore 206. The pin 208 may be axially retained within the first housings 201 and the second housing 204. As shown in FIG. 2, a plate 219, coupled to each of the first housing 201 by fasteners 221, may axially retain the pin 208. In an embodiment, the pin 208 may also be rotationally retained through the plate 219. The rotational retention of the pin 208 may be achieved by welding, mechanical fasteners or any other known methods. Further, the plate 219 may also absorb thrust loads exerted by the pin 208.

The pin joint 116 further includes a bearing member 214. The bearing member 214 may have a substantially hollow cylindrical shape having a first end 215 and a second end 217. The bearing member 214 includes an inner surface 216 and an outer surface 218 extending between the first end 215 and second end 217. The bearing member 214 may be co-axially received within the elongate bore 206 of the second housing 204. The outer surface 218 of the bearing member 214 is coupled to the second housing 204. In an embodiment, the outer surface 218 of the bearing member 214 may be press-fitted to the second housing 204. In another example, the bearing member 214 may be secured to the second housing 204 by processes such as welding, adhesives, fasteners, and the like. As shown in FIG. 2, the inner surface 216 of the bearing member 214 faces the outer surface 210 of the pin 208. In an embodiment, the inner surface 216 of the bearing member 214 may include a coating 220. In an embodiment, the coating 220 may be a lubricant coating. The lubricant coating may be at least one of graphite, Polytetrafluoroethylene (PTFE), and molybdenum disulfide. In another embodiment, the coating 220 may be a wear resistant coating. The wear resistant coating may be at least one of High Velocity Oxy Fuel (HVOF) chrome carbide, and laser clad stainless steel. In yet another embodiment, the coating 220 may be a composite coating containing elemental molybdenum (Mo), for example, Cu-15Ni-8Sn and Mo, brass and Mo etc. The coating 220 may be provided by thermal spraying, laser cladding, or any other known methods. The bearing member 214 further includes at least one shoulder portion 222 and at least one groove portion 224. The groove portion 224 and the shoulder portion 222 are disposed proximate to the first end 215 and second end 217 respectively, of the bearing member 214. The shoulder portion 222 may extend radially towards the outer surface 210 of the pin 208.

The pin joint 116 further includes an insert member 226. The insert member 226 may have a substantially hollow cylindrical shape having the inner surface 228, an outer surface 230, a first lateral surface 232, and a second lateral surface 234. The first lateral surface 232 is distal to the second lateral surface 234 along the pivot axis P-P'. The insert member 226 may be co-axially received within the elongate bore 206 of the second housing 204. The first lateral surface 232 and the second lateral surface 234 are substantially perpendicular to the pivot axis P-P'. Further, the second lateral surface 234 is adjacent to the shoulder portion 222 and the first lateral surface 232 is adjacent to the groove portion 224. The insert member 226 may be manufactured using any method known in the art, such as extrusion, casting, molding etc. In an embodiment, the insert member 226 may be one of a machined metal tube stock bearing, an extruded plastic tube stock bearing, laminated bi-metallic bearing, powdered metal bearing and composite non-metallic bearing (e.g., a fiber and resin composite). The insert member 226 may be made of suitable bearing material such as, steel, bronze, plastic etc. In an embodiment, each of the inner surface 228, the outer surface 230, the first lateral surface 232, and the second lateral surface 234 may include a coating 236. In an alternative embodiment, the inner surface 228 and the outer surface 230 may include the coating 236, and the first and second lateral surfaces 232, 234 may not include a coating. In an embodiment, the coating 236 may be a lubricant coating. The lubricant coating may be at least one of graphite, Polytetrafluoroethylene (PTFE), and molybdenum disulfide. In another embodiment, the coating 236 may be a wear resistant coating. The wear resistant coating may be at least one of High Velocity Oxy Fuel (HVOF) chrome carbide, and laser clad stainless steel. In yet another embodiment, the coating 236 may be a composite coating containing elemental molybdenum (Mo), for example, Cu-15Ni-8Sn and Mo, brass and Mo etc. The coating 236 may be provided by thermal spraying, laser cladding, or any other known methods.

The insert member 226 is disposed between the outer surface 210 of the pin 208 and the inner surface 216 of the bearing member 214. In an embodiment, the insert member 226 may be disposed between the pin 208 and the bearing member 214 by a zero clearance fit. Due to the zero clearance fit, a diameter of the outer surface 210 of the pin may be substantially equal to a diameter of the inner surface 228 of the insert member 226 along with the coating 236. Further, a diameter of the inner surface 216 of the bearing member 214 may be substantially equal to a diameter of the outer surface 230 of the insert member 226 along with the coating 236. The zero clearance fit may be configured to become a sliding fit between the insert member 226, and the pin 208 and the bearing member 214 during relative movement between the first housing 201 and the second housing 204 during an operation of the machine 100. In an alternative embodiment, the insert member 226 may be disposed between the bearing member 214 and the pin 208 by a sliding fit. The sliding fit between the insert member 226 and the pin 208 may enable an inner surface 228 of the insert member 226 to rotate freely relative to the outer surface 210 of the pin. Similarly, the sliding fit between the insert member 226 and the bearing member 214 may enable the insert member 226 to rotate freely relative to the inner surface 218 of the bearing member 214.

In an embodiment, the insert member 226 is axially retained in the pin joint 116 by a retaining system 238. The retaining system 238 may constrain an axial movement of the insert member 226 along the pivot axis P-P'. The axial movement of the insert member 226 at the second lateral surface 234 is constrained by the shoulder portion 222. A thrust washer 242 may also be disposed between the shoulder portion 222 and the second lateral surface 234. Alternatively, the thrust washer 242 may not be present. An axial movement of the insert member 226 at the first lateral surface 232 may be restrained by a retaining ring 240 and the thrust washer 242. The retaining ring 240 is configured to be detachably received in the groove portion 224 of the bearing member 214. In an example, the retaining ring 240 may be a stamped or spiral wound steel ring or the like. The thrust washer 242 is disposed between the first lateral surface 232 and the retaining ring 240. The thrust washers 242 may include a coating 243. In an embodiment, the coating 243 may be a lubricant coating. The lubricant coating may be at least one of graphite, Polytetrafluoroethylene (PTFE), and molybdenum disulfide. In another embodiment, the coating 243 may be a wear resistant coating. The wear resistant coating may be at least one of High Velocity Oxy Fuel (HVOF) chrome carbide, and laser clad stainless steel. In yet another embodiment, the coating 243 may be a composite coating containing elemental molybdenum (Mo), for example, Cu-15Ni-8Sn and Mo, brass and Mo etc. The coating 243 may be provided by thermal spraying, laser cladding, or any other known methods. Further, the thrust washers 242 may be made of bronze. Alternatively, the thrust washers 242 may not include any coating.

Further in an embodiment, the pin joint 116 includes a plurality of seals 244. In an example, the plurality of seals 244 may be lip seals pressed into opposing ends of the bearing member 214. As shown in FIG. 2, the seals 244 are disposed on the bearing member 214 adjacent to the shoulder portion 222 and the groove portion 224. The seals 244 are configured to maintain a fluid tight seal between the pin 208 and the bearing member 214. The seals 244 may be configured to restrict entry of debris, dust, or any other foreign material from entering the elongate bore 206 of the second housing 204. In an embodiment, the lip seals 244 may be detachably coupled to the bearing member 214. The seals 244 and the retaining ring 240 may be conveniently detached from the bearing member 214 in order to replace the insert member 226.

The pin joint 116, as described above, is exemplary in nature and variations are possible within the scope of the present disclosure. In an example, a lubricant, such as grease may be used in addition to the coatings 220, 236, 243 of the pin 208, the bearing member 214, the insert member 226 and the thrust washers 242, respectively. Alternatively, the coatings may not be present, and grease or any other suitable lubricant may be used to provide lubrication.

FIG. 3 illustrates a sectional view of a pin joint 500, according to yet another embodiment of the present disclosure. A bearing member 502 of the pin joint 500 includes a first groove portion 504 and a second groove portion 506 proximate to a first end 508 and a second end 510, respectively. A retaining system 512 for the insert member 226 includes the retaining rings 240 disposed in the first and second groove portions 504, 506. In such a configuration, the insert member 226 may be replaced by removing the seals 244 and the retaining rings 240 from one of the first end 508 and the second end 510 of the bearing member 502.

FIG. 4 illustrates a pin joint 600, according to a further embodiment of the present disclosure. The pin joint 600 includes a first housing 602 and second housings 604 located on both sides of the first housing 602. In an embodiment, the first housing 602 is stationary and the second housings 604 are pivotal relative to the first housing 602. The first and second housings 602, 604 define aligned bores 606, 608 therein, respectively. Further, a pin 610 is at least partly received within aligned bores 606 and 608. The pin 610 includes a shoulder portion 612 adjacent to the first lateral surface 232 of the insert member 226. Further, a plate 614 may be coupled to the second housing 604 via the fasteners 616. In an embodiment, the plate 614 may include a coating 618 facing the second lateral surface 234 of the inert member 226. The retaining system 620 for the insert member 226 includes the shoulder portion 612 of the pin 610 and the plate 614. Further, a bearing member 622 includes a coating 626 on an inner surface 624 of the insert member 226. In an embodiment, the coating 618, 626 may be a lubricant coating. The lubricant coating may be at least one of graphite, Polytetrafluoroethylene (PTFE), and molybdenum disulfide. In another embodiment, the coating 618, 626 may be a wear resistant coating. The wear resistant coating may be at least one of High Velocity Oxy Fuel (HVOF) chrome carbide, and laser clad stainless steel. In yet another embodiment, the coating 618, 626 may be a composite coating containing elemental molybdenum (Mo), for example, Cu-15Ni-8Sn and Mo, brass and Mo etc. The coating 618, 626 may be provided by thermal spraying, laser cladding, or any other known methods. The insert member 226 may be replaced by detaching the plate 614 from the second housing 604.

FIG. 5 illustrates a perspective view of an insert member 700, according to an embodiment of the present disclosure. The insert member 700 may be used with one or more of the pin joints 116, 500, 600 described above. In an embodiment, the insert member 700 may be a roll formed insert with uniform thickness, i.e., the insert member 700 is manufactured by roll forming a flat metal plate of suitable bearing material to achieve a substantially hollow cylindrical shape. The roll formed ends of the flat plate defines a gap 702 between them. A width of the gap 702 may be varied based on various manufacturing and design requirements. The insert member 700 may be made of suitable material, such as steel, bronze, aluminum, laminated bi-metals etc. In another example, the insert member 700 may be a roll formed plastic. Further in an embodiment, the insert member 700 includes a plurality of channels 704 extending between an inner surface 706 and an outer surface 708 thereof. The plurality of channels 704 may be configured to receive and retain a lubricant between the insert member 700 and other interfacing components of the pin joints 116, 500, 600. The channels 704 may also allow a flow of lubricant between the inner and outer surfaces 706, 708 of the insert member 700. This may allow uniform distribution of the lubricant around the insert member 700. In various alternative embodiments, the insert member 700 may include a plurality of recesses, indentations, pockets, and the like on at least one of the inner surface 706 and the outer surface 708. Further, the insert member 700 may also include a lubricant coating or a wear resistant coating (not shown) on one or more surfaces. The various structural features, such as the channels 704, and the lubricant coating or wear resistant coating may be first provided on the flat plate and subsequently, the flat plate may be roll formed to obtain the insert member 700. Industrial Applicability

The present disclosure is related to pin joints 116, 500, 600 for a machine 100. The pin joints 116, 500, 600 may pivotally connect the first implement member 120 with the second implement member 114 of the implement system 111 of the machine 100. An exemplary operation of the pin joint 116 will be described hereinafter.

During a pivotal movement of the second implement member 114 relative to the first implement member 120, the second housing 204 may rotate relative to the first housings 201. The bearing member 214 may support such rotation of the second housing 204. The inner surface 216 of the bearing member 214 and the outer surface 230 of the insert member 226 may be freely rotatable relative to each other due to the sliding fit therebetween. Further, the coatings 220 and 236 on the bearing member 214 and the insert member 226, respectively, may minimize friction and wear. Further, the inner surface 228 of the insert member 226 may be freely rotatable relative to the outer surface 210 of the pin 208 die to the sliding fit therebetween. Further, the coating 236 on the insert member 226 may minimize friction and wear. The coating 243 on the thrust washers 242 may also minimize friction and wear between the thrust washers 242 and the other interfacing components of the pin joint 116.

The insert member 226 may prevent direct contact between the bearing member 214 and the pin 208 as the insert member 226 is disposed therebetween. This may prevent galling between the bearing member 214 and the pin 208. Further, a material of the insert member 226 may be chosen such that the insert member 226 acts as a sacrificial component, thereby preventing substantial wear and/or failure of the bearing member 214 and the pin 208. Therefore, maintenance and/or replacement costs of the bearing member 214 and the pin 208 may be reduced. The material and/or design of the insert member 226 may also be selected based on design requirements of the pin joint 116. For example, based on lubrication requirements, inner and outer surfaces 228, 230 may be modified by providing recesses, pockets, and the like. Moreover, the insert member 226 may enable two separate sliding interfaces on the inner and outer surfaces 228, 230 thereof. Therefore, in case there is a failure and/or adhesion at one of the sliding interfaces, the other sliding surface may enable a functioning of the pin joint 116. Further, the pin joint 116 may also be conveniently assembled and/or disassembled. This may facilitate replacement of the insert member 226. The insert member 226 may require periodic replacement due to wear. The present disclosure is also related to a method of assembling the pin joint 116. FIG. 6 illustrates a flowchart of a method 800 for assembling the pin joint 116, according to an embodiment of the present disclosure. At step 802, the method 800 includes providing a pin 208 at least partly within the first housing 201 and the second housing 204. The pin 208 is disposed co-axially with respect to the pivot axis P-P'.

At step 804, the method 800 includes providing an insert member

226 between the inner surface 216 of the bearing member 214 and the outer surface 210 of the pin 208. At step 806, the method 800 includes providing a sliding fit between the outer surface 230 of the insert member 226 and the inner surface 216 of the bearing member 214. At step 808, the method 800 includes providing a sliding fit between the inner surface 228 of the insert member 226 and the outer surface 210 of the pin 208. In an alternative embodiment, the insert member 226 may be disposed between the pin 208 and the bearing member 214 by a zero clearance fit. The zero clearance fit may be configured to become a sliding fit during operation of the pin joint 116.

At step 810, the method 800 includes axially retaining the insert member 226 between the pin 208 and the bearing member 214. As explained earlier, the insert member 226 may be axially retained within the pin joint 116 via the retaining system 238. In case of the pin joints 500, 600, the insert member 226 may be axially retained by the respective retaining systems 512, 620. The seals 244 may then attached to the insert member 226. The plate 219 may be then coupled to the first housing 201 via the fasteners 221.

A method of disassembling the pin joint 116 for replacement of the insert member 226 may include removing the plate 219 from the first housing 201. The pin 208 may be then slid out of the first and second housings 201, 204. The seals 244 may be then removed from the insert member 226. The retaining ring 240 is detached from the groove portion 224. The thrust washer 242 may then removed. Subsequently, the insert member 226 is removed from the first and second housings 201, 204. A new insert member (not shown) may be the inserted within the second housing 204 and the pin joint 116 assembled accordingly. Thus, the pin joint 116 may allow easy and quick replacement of the insert member 226 without requiring any special tools, such as a hydraulic press.

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.