JP6917022B2 - Construction machinery arm - Google Patents

Description

The present invention relates to an arm of a construction machine.

The arm of a construction machine has a hollow structure having a square cross section in which steel plates are connected by welding (Patent Document 1). The arm has an attachment cylinder support shaft that pivotally supports the cylinder of the attachment cylinder, a boom connecting shaft that connects the boom, and an arm cylinder connecting shaft that connects the rod of the arm cylinder pivotally supported by the boom at the rear. Further, the arm has an attachment connecting shaft for connecting the attachment, and an attachment cylinder connecting shaft for connecting the rod or link of the attachment cylinder pivotally supported by the arm at the tip. The hydraulic piping to the attachment cylinder and the attachment operating cylinder is attached to the upper surface or the side surface of the arm, or is inserted inside the arm.

Japanese Unexamined Patent Publication No. 09-165773

The conventional arm is composed of an arm body having a hollow structure with a square cross section in which steel plates are connected by welding, and a boom connecting bracket that supports an attachment cylinder and is used for connecting to a boom. The boom connecting bracket may be an extending portion of a steel plate constituting the arm body, or may be welded to the steel plate separately from the arm body. Normally, the arm is transported while being attached to a construction machine, so it does not matter if the boom connecting bracket protrudes from the arm body. However, when the arm is transported or stored as a single unit, if the boom connecting bracket protrudes from the arm body, it may become bulky and may damage another arm or other members. Therefore, for the purpose of reducing the bulk of transportation or storage, an arm capable of easily assembling or disassembling the arm body and the boom mounting bracket was examined.

The one developed as a result of the study is an integrally molded arm body with a mounting hole on the attachment side in the left-right direction at the front and a joint hole on the body side in the left-right direction at the rear, and a boom-side mounting hole and bracket side in the left-right direction. is composed of a boom connecting bracket integrally molded provided with a joining hole, this body-side joining hole and the bracket side joining hole communicated with the left-right direction through the fastening bolt, by tightening the joint nut to said fastening bolt, the arm body It is an arm of a construction machine that is assembled with a boom connecting bracket. The material constituting the arm body and the boom connecting bracket shall be the same steel material as before, a metal having a lighter specific gravity than steel containing a light metal or an alloy of the light metal, an alloy of the metal, or a specific strength equal to or higher than that of the metal. Resin or ceramics.

The attachment side mounting hole mounts an attachment connecting shaft for connecting the attachment and an attachment link lever connecting shaft for supporting the attachment link lever that supports the rod of the attachment cylinder. The boom-side mounting hole mounts an attachment cylinder support shaft that supports the tube of the attachment cylinder, a boom connecting shaft that connects the boom, and an arm cylinder connecting shaft that connects the rod of the arm cylinder. The arm main body and the boom connecting bracket are assembled by tightening the joint bolts and joint nuts inserted into the main body side joint holes and the bracket side joint holes.

When the material constituting the integrally molded arm body and the boom connecting bracket is metal, the weight of the arm can be reduced if either or both of them are made of metal having a lower specific density than steel. Examples of the metal that reduces the weight of the arm or the alloy of the metal include an aluminum alloy, a titanium alloy, a magnesium alloy, a nickel alloy, and the like. Further, when the material constituting the integrally molded arm body and the boom connecting bracket is resin or ceramics, fiber reinforced plastic or fine ceramics can be exemplified. The materials that make up the arm body and boom connecting bracket do not matter. The joint bolts and nuts are made of the same or different materials as the arm body or boom connecting bracket.

The outer shape of the arm body is not limited, but if it is a pyramid-shaped block having a tapered square cross section, it is similar in appearance to the conventional arm, and for example, the hydraulic piping can be routed in the same manner as before, which is preferable. The boom connecting bracket becomes a block-shaped member or a plate-shaped member when it is inserted into a connection groove formed in the center of the left and right sides of the arm body, and becomes a plate-shaped member when it is attached to the side surface of the arm body. The number of joint bolts for assembling the arm body and the boom connecting bracket shall be two or more. However, as will be described later, when a spacer that integrates a pair of left and right boom connecting brackets is used together, if one of the spacers can be inserted into the arm body, one joining bolt can be used instead of the connecting bolt that tightens the spacer. Can be.

The arm body is an integrally molded block provided with a lightening hole hollowed out in the front-rear direction and a communication hole in the left-right direction crossing the lightening hole, and the communication hole provided at the tip is in the left-right direction. The attachment hole is used, and the communication hole provided at the rear is a bracket side joint hole in the left-right direction. The lightening hole may or may not be penetrated through the block from the front portion (rear portion) to the rear portion (front portion). The lightening hole and the communication hole may have a square cross section, regardless of the cross-sectional shape. However, the lightening holes and communication holes are basically circular in cross section, which has no uneven distribution of stress and is easy to cut.

Further, the boom coupling bracket pair Oh is, a plate-shaped member integrally molded, each provided with a connecting bolt insertion hole and the lateral direction of the boom side joining hole, the left and right boom connecting bracket across the arm body The main body side joint hole and each bracket side joint hole are communicated, assembled to the arm main body by the joint pin passed through the main body side joint hole and the bracket side joint hole, the spacer is sandwiched between the parts that do not sandwich the arm main body, and the connecting bolt is inserted. The connecting bolt inserted through the hole is tightened to the spacer so that the left and right sides are integrated via the spacer. The spacer is made of the same or different material as the boom connecting bracket.

Since the arm of the construction machine of the present invention is configured by joining a separately integrally molded arm body and boom connecting bracket with connecting bolts without requiring welding, it can be easily assembled or disassembled during transportation or storage. Further, since the arm body and the boom connecting bracket can be assembled without welding, the arm body and the boom connecting bracket can be configured with a light metal that is difficult to weld, and the weight of the arm can be reduced. The weight reduction of the arm brings about a reduction in fuel cost during transportation. Further, since the arm of the construction machine of the present invention can disassemble the arm body and the boom connecting bracket, the occupied area can be reduced during transportation and storage. Further, the arm of the construction machine of the present invention can be flexibly adapted to various booms by changing the combination of the arm body and the boom connecting bracket.

The arm body is an integrally molded block provided with a lightening hole hollowed out in the front-rear direction and a communication hole in the left-right direction crossing the lightening hole, thereby realizing a structure having an integral structure of the same material. However, the weight can be reduced by the lightening holes and the communication holes while ensuring the strength and rigidity. When the material constituting the block is an aluminum alloy or a titanium alloy, it is particularly difficult to cut, so it is desirable to reduce the number of processed parts. Further, the communication hole can be used as an attachment side mounting hole or a connecting bolt insertion hole, and it is not necessary to separately provide an attachment side mounting hole or a connecting bolt insertion hole.

When the boom connecting bracket has a pair of left and right configurations, the boom connecting bracket can be thinly configured as an integrally molded plate-shaped member, so that the weight can be sufficiently reduced as a portion for connecting the boom and the number of processed parts is reduced. As a result, the processing cost of the portion connecting the booms is reduced, the configuration of the boom connecting bracket is simplified, and the strength or rigidity can be easily maintained. In addition, since the pair of left and right boom connecting brackets have different replacement units for left and right due to damage or the like, there is an advantage that maintenance cost due to parts replacement can be reduced.

It is a side view which shows the example of the construction machine which assembled the example of the arm to which this invention was applied. It is a perspective view of the arm of this example. It is an exploded perspective view of the arm of this example. It is a right side view of the arm of this example. It is a top view of the arm of this example. It is a bottom view of the arm of this example. It is a front view of the arm of this example. It is a rear view of the arm of this example.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. As seen in FIG. 1, the arm 3 of the present invention can be used with respect to the existing construction machine 1 as in the conventional case. In the arm 3 of this example, the attachment 4 is connected by the attachment connecting shaft 41 attached to the tip of the arm body 31, and the shaft end of the link lever 43 is connected by the attachment link lever connecting shaft 42 attached to the tip of the arm body 31. In connection with each other, the rod 371 of the attachment cylinder 37 is connected to the swinging end of the link lever 43, and the swinging end and the attachment 4 are connected by a link 44.

Further, the arm 3 of this example is connected to the boom 2 by a boom connecting shaft 21 attached to a pair of boom connecting brackets 32 sandwiching the arm body 31, and is armed by an arm cylinder connecting shaft 22 attached to the connecting bracket 32. The rod 231 of the cylinder 23 is connected. The boom connecting bracket 32 makes the attachment cylinder swingable by the attachment cylinder connecting shaft 372. As described above, the arm 3 of the present invention can be used in place of the conventional arm because the connection relationship between the boom 2 and the attachment 4 and the support structure of the attachment cylinder 37 can be configured in the same manner as in the conventional case.

As seen in FIGS. 2 to 8, the arm 3 of this example is made of extra super duralumin (aluminum alloy), and has an attachment side mounting hole 311 at the front and a main body side joint hole 312 at the rear. and 31, a boom connecting bracket 32 provided with a boom-side mounting hole 321 and bracket side joining hole 322 in the same ultra duralumin, through fastening bolt 33 of the present body-side joining hole 312 and the bracket side joining hole 322 communicates, constructed by assembling by tightening the joint nut 331 on the fastening bolt 33.

The arm body 31 is a pyramid-shaped extra super duralumin block having a tapered square cross section, which is similar in appearance to the conventional arm, and is integrally molded by machining. The hydraulic pipes and the like are routed along the outer surface as in the conventional case (for convenience of illustration, the hydraulic pipes and the like are not shown). The arm body 3 of this example is provided with a lightening hole 313 hollowed out from the front end to the rear and a communication hole 314 crossing the lightening hole 313 in order to reduce the weight. The attachment side mounting hole 311 also serves as a communication hole provided at the tip. Further, the main body side joint hole 312 provided at the front-rear intermediate position is one of the communication holes.

The boom connecting bracket 32 is a plate-shaped member made of extra super duralumin whose side view is substantially rhombic, and is integrally molded as a whole by machined processing. The boom connecting bracket 32 of this example has a pair of left and right mirror-symmetrical structures along the left and right sides of the arm body 31, and bracket side joint holes 322 are provided on the front and back of the lower side along the lower surface of each arm body 31, and the front and back of the upper side. Is provided with a boom-side mounting hole 321. The left and right boom connecting brackets 32 are assembled to the arm body 31 by the joining bolts 33 and the connecting bolts 35 with the arm body 31 and the three spacers 34 sandwiched between them.

The pair of left and right boom connecting brackets 32 first communicate the bracket side joining hole 322 in front of the lower side with the main body side joining hole 312 provided at the front and rear intermediate position of the arm main body 31, and penetrate from the side of one boom connecting bracket 32. The joined bolt 33 is engaged with the joined nut 331 on the side of the other boom connecting bracket 32. The bracket-side joint hole 322 behind the lower side fits the bush 36 and penetrates the boom connecting shaft 21. The arm body 31 and the pair of left and right boom connecting brackets 32 are also integrated by the boom connecting shaft 21.

The pair of left and right boom connecting brackets 32 are positioned at the left and right positions by sandwiching a cylindrical spacer 34 in a portion protruding from the upper surface of the arm body 31 and screwing the connecting bolt 35 inserted through the bolt through hole 351 into the spacer 34. The relationship and posture are fixed and integrated. Like the arm body 31, the spacer 34 can be made of extra super duralumin, but when considering the process of carving female screws, it may be made of steel as in the past because it is a small member and does not impair weight reduction. ..

In addition, the pair of left and right boom connecting brackets 32 are combined with the engagement of the joining bolt 33 and the joining nut 331 by screwing the connecting bolt 35 into the bolt screw hole 352 of the main body arm 31 through the bolt through hole 351. , It is integrated with the main body arm 31 without rattling. In this way, the arm body 31 and the pair of left and right boom connecting brackets 32 are assembled. Since the arm body 31 and the pair of left and right boom connecting brackets 32 are assembled using separable joining bolts 33 and connecting bolts 35, they can be easily disassembled.

The present invention provides an arm 3 that does not require welding. This has the advantage that a metal that is difficult to weld but is lightweight can be selected as the material for the arm body 31 and the boom mounting bracket 32, which contributes to the weight reduction of the arm 3. The lightweight arm 3 not only reduces the transportation cost, but also improves the boom raising / lowering speed and suspension capacity when assembled to the construction machine 1, and increases the amount of excavated soil and the cycle time. Improve productivity by shortening. When the arm body 31 and the boom mounting bracket 32 are made of extra super duralumin as in this example, the weight is about half that of the conventional arm made of steel plate as a substitute, and compared with the conventional arm, The boom raising / lowering speed and suspension capacity will be improved by about 10%, the amount of excavated soil will be increased by about 5%, and the cycle time will be shortened by about 5%.

1 Construction machinery 2 Boom
21 Boom connecting shaft
22 Cylinder connecting shaft for arm
23 Cylinder for arm
231 Cylinder rod for arm 3 Arm
31 Arm body
311 Attachment side mounting hole
312 Body side joint hole
313 lightening hole
314 communication hole
32 Boom connecting bracket
321 Boom side mounting hole
322 Bracket side joint hole
33 Joining bolt
331 Joint nut
34 spacer
35 connecting bolt
351 Bolt through hole
352 Bolt screw hole
36 bush
37 Attachment swing cylinder
371 rod
372 Attachment swing cylinder connecting shaft 4 Attachment
41 Attachment connecting shaft
42 Attachment link lever connecting shaft
43 Link lever
44 links

Claims (3)

An integrally molded arm body with a left-right attachment-side mounting hole at the front and a left-right main-side joint hole at the rear, and an integrally-molded arm body with a left-right boom-side mounting hole and bracket-side joint hole. Consists of a boom connecting bracket
An arm of a construction machine in which an arm main body and a boom connecting bracket are assembled by communicating a main body side joint hole and a bracket side joint hole in the left-right direction, passing a joint bolt through the joint bolt, and tightening a joint nut to the joint bolt. The arm body is an integrally molded block provided with a lightening hole hollowed out in the front-rear direction and a communication hole in the left-right direction crossing the lightening hole.
The communication hole provided at the tip is a mounting hole on the attachment side in the left-right direction.
The arm of the construction machine according to claim 1, wherein the communication hole provided at the rear portion is a joint hole on the bracket side in the left-right direction. Boom connecting bracket, pair Oh is, a plate-shaped member integrally molded, each provided with a connecting bolt insertion hole and the lateral direction of the boom side joining hole,
The left and right boom connecting brackets communicate the main body side joint holes and the respective bracket side joint holes with the arm body sandwiched between them, and tighten the joint nuts to the joint bolts passed through the main body side joint holes and the bracket side joint holes. Assemble to the main body,
The arm of a construction machine according to claim 1 or 2, wherein a spacer is sandwiched between portions that do not sandwich the arm body, a connecting bolt inserted through a connecting bolt insertion hole is tightened to the spacer, and the left and right sides are integrated via the spacer.

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