JP4569381B2 - Piping structure of hydraulic excavator - Google Patents

Description

The present invention, in a hydraulic excavator of a so-called swing type, to a piping structure for passing along the hydraulic hoses to the boom of the excavation attachment.

  As shown in FIG. 7, the swing type hydraulic excavator has an upper swing body 2 mounted on a crawler type lower traveling body 1 so as to be rotatable about a vertical axis. A boom 3 and an arm 4 are mounted on the upper swing body 2. , A bucket 5, and a boom, an arm, and bucket cylinders (hydraulic cylinders) 6, 7, and 8 for operating the bucket 5 and a drilling attachment 9 are mounted.

  The boom 3 of the excavation attachment 9 is attached to the upper swing body 2 so that it can swing left and right (swivel and swivel) and can move up and down.

  8 and 9, the swing bracket 10 is attached to the upper swing body 2 so that the swing bracket 10 can swing to the left and right about the swing pins (vertical axes) 11 and 11, and the boom base end portion can be pivoted. A boom foot 12 is attached to the swing bracket 10 by a horizontal boom foot pin 13.

  In FIG. 7, reference numeral 14 denotes a swing cylinder that swings the swing bracket 10. Further, a pair of left and right bushes 15 (only one side is shown) are provided in a pin through hole through which the boom foot pin 13 is passed in the boom foot 12, and the boom load is supported by this bush portion.

  In this hydraulic excavator, a hydraulic hose (see FIG. 9) 16 for connecting arms and bucket cylinders 7 and 8 to a hydraulic pump and a tank (not shown) mounted on the upper swing body 2 via a switching valve is generally used. A path is provided through the inner space of the swing bracket 10 from the lower side of the boom base end toward the boom rear surface side, and extends upward along the boom rear surface to reach both cylinders 7 and 8.

  In this case, the hydraulic hose 16 is provided with a certain margin in length so as to be able to follow the boom operation without difficulty, and this margin swells rearward on the boom rear side when the boom 3 is raised.

As another piping structure, as shown in Patent Document 1, the boom foot 12 is formed in a bifurcated shape, and the hydraulic hose 16 extending from the swing bracket 10 passes through the bifurcated portion of the boom foot 12 and is boomed. A structure leading to the back side has been proposed.
JP 2003-176548 A

  However, according to the conventional piping structure shown in FIG. 9, a portion 16a of the hydraulic hose 16 that curves backward from the swing bracket 10 (hereinafter referred to as a rear curved portion) bulges greatly rearward, and this swollen backward curve. The portion 16a may interfere with the front portion of the upper swing body 2.

  The reason why the rearward bulge of the rear curved portion 16a is increased is as follows.

  (i) The radius of curvature of the rear curved portion 16a is minimized when the boom 3 is tilted as shown by a two-dot chain line in FIG. Since the radius of curvature at this time is a dimension that can bypass the outer periphery of the boom foot 12, the bulge of the rear curved portion 16a in the boom standing state is increased by the surplus due to the bypass.

  (ii) The margin of the length to be given to the hydraulic hose 16 includes a rear curved portion 16a and a portion continuous below the rear curved portion 16a, that is, a curved portion located below the boom foot in the swing bracket 10 (hereinafter referred to as a downward curved portion). 16b).

  Therefore, if the radius of curvature of the downward curved portion 16b can be increased, the amount of backward protrusion of the backward curved portion 16a can be reduced accordingly.

  However, since the upper limit position of the downward curved portion 16b is limited by the base end surface of the boom foot 12 (the lower end surface when the boom is upright), the radius of curvature of the portion 16a cannot be increased beyond the current level.

  Under such circumstances, in order to avoid interference between the rear curved portion 16a and the front portion of the upper swing body 2, the distance between the two must be sufficiently large, and the excavation attachment 9 is positioned forward by that amount. Therefore, there was a problem that the stability of the excavator deteriorated.

  On the other hand, according to the technique described in Patent Document 1, a large bulge to the rear of the hydraulic hose 16 is eliminated, but a decrease in strength of the boom foot 12 due to the boom foot 12 being bifurcated is inevitable. Further, the load supporting force is also reduced because the size of the load supporting portion (the portion where the bush 15 is mounted) is reduced.

  For this reason, for example, a new measure for covering a decrease in strength and load bearing capacity, such as increasing the width and thickness of the boom foot 12 or adding a reinforcing structure, is necessary, which is extremely expensive in terms of design and cost. Disadvantageous.

The present invention, without causing harmful effects such as reduction in the strength of the boom foot, there is provided a piping structure of a hydraulic excavator which can minimize the bulge rearward hydraulic hoses.

The inventions of claim 1, together with the swing bracket on the upper swing structure of the base machine is mounted rotatably around the vertical axis, a boom foot, rotatably about a horizontal boom foot pin to the swing bracket mounted, hydraulic hose, in the piping structure of the hydraulic excavator provided with route around to the boom back side curved rearward from the base end side lower street boom foot inside the swing bracket, a boom width direction of the boom foot A guide recess is provided in the central portion of the hydraulic hose along the rear curved portion of the hydraulic hose when the boom is tilted, and the boom hose is connected to the rear curved portion and below the rear curved portion. A state in which the upper portion of the lower curved portion located below the upper portion of the lower portion is fitted in the guide recess and is along the boom foot. , In which through the boom base end lower the boom back side.

According to the present invention, a guide recess is provided at the center of the boom foot in the boom width direction along the rearward curved portion of the hydraulic hose when the boom is tilted, and the hydraulic hose is disposed on the rearward curved portion and the rearwardly curved portion. The upper end portion of the lower curved portion located below the boom foot continuously below the rear curved portion is fitted in the guide recess and extends along the boom foot from the lower side of the boom proximal side to the rear side of the boom. Since it has passed, it is possible to suppress the rearward bulging of the hydraulic hose in the boom standing state by the following two points.

While defeating (I) boom, it is possible to back curve component in the hydraulic hose to reduce the radius of curvature of the part by fitted into the boom foot guide recess. For this reason, the radius of curvature of the rear curved portion in the boom standing state can also be reduced, and the rearward projection amount can be suppressed.

  (II) Since the upper part of the downward curved portion of the hydraulic hose is fitted into the guide recess, the upper end position of the same portion is increased and the curvature radius can be increased. The radius of curvature can be reduced.

In addition, since only the central part of the boom foot in the boom width direction is recessed, there is almost no possibility of adversely affecting the strength and load supporting force of the boom foot as compared with the case where the boom foot is bifurcated .

  An embodiment of the present invention will be described with reference to FIGS.

  In the following embodiments, the same parts as those shown in FIGS. 7 to 9 are denoted by the same reference numerals, and redundant description thereof is omitted.

  The boom 17 according to the embodiment includes a boom foot 19 formed by forging, casting or the like at the base end of a box-shaped boom body 18 as shown in FIGS. The boom foot 19 is attached to the swing bracket 10 mounted on the upper swing body 2 so as to be rotatable around the same pin by the boom foot pin 13 (see FIG. 2).

  The boom foot 19 is provided with a guide recess 20 at the center in the boom width direction for allowing the hydraulic hose 16 as the hydraulic piping for the arm and bucket cylinders 7 and 8 in FIG.

  As shown in FIG. 3, the guide recessed portion 20 is bent along the rear curved portion 16 c that curves from the lower side of the boom proximal end and turns around the boom back side in a state where the boom 17 is tilted as shown in FIG. 3. It is provided across the front surface of the foot 19, the base end surface (the lower end surface in the boom standing state shown in FIG. 4), and the back surface.

  Thus, as shown in FIG. 3, most of the rear curved portion 16 c of the hydraulic hose 17 is configured to fit into the guide recess 20 in a state where the boom 17 is tilted.

  In addition, the lower end side of the rear curved portion 16c is introduced into the guide concave portion 20, and the upper end side exits from the guide concave portion 20 to the outside of the rear face of the boom. For this reason, the guide recessed part 20 is provided in the form where the front side which is an introduction side is deepest, and becomes shallow gradually toward the back side.

  According to the said structure, the curvature radius of the back curved part 16c in the state which fell the boom 17 can be made small minimum.

  For this reason, as shown in FIG. 4, the curvature radius of the back curve part 16c in the state which raised the boom 17 can also be made small.

  Further, since the upper end portion of the lower curved portion 16d (the lower end portion of the rear curved portion 16c) that continues below the rear curved portion 16c fits into the guide recess 20 in the boom standing state as shown in the drawing, The upper end position is higher than in the conventional case, and the radius of curvature is increased. For this reason, the curvature radius of the back curved portion 16c can be reduced by the amount of increase in the curvature radius of the downward curved portion 16d within a certain excess length.

  In FIGS. 3 and 4, the conventional rear and lower curved portions 16a and 16b are shown by two-dot chain lines for comparison.

  From the above points, it is possible to suppress the rearward protruding amount of the rear curved portion 16c. Therefore, it is not necessary to increase the distance between the two parts in order to avoid the interference between the part 16c and the upper swing body 2 (the excavation attachment 9 in FIG. 7 is shifted forward), so that the stability of the shovel is improved. Can do.

  Moreover, the center part of the boom foot 19 in the boom width direction, which has nothing to do with the boom foot strength and load support force, is basically just recessed (squeezed), so compared with the case where the boom foot is bifurcated. Thus, there is almost no possibility of adversely affecting the boom foot strength and load supporting force.

  By the way, in the said embodiment, although the case where the boom foot 19 was formed in the block shape of a block was illustrated, as shown in FIG. 6 as another embodiment, the boom foot 19 is formed in a cylindrical boss shape, and the outer peripheral surface is formed in it. A guide recess 20 may be provided.

  Even in this case, the guide recess 20 can be provided in substantially the same form as in the first embodiment, and basically the same operational effects can be obtained.

  Moreover, in the said embodiment, although the case where the hydraulic hose 16 was provided in the path | route from the boom foot lower part to the back curve part 16d through the inside of the swing bracket 10 was illustrated as the most general form, this invention is hydraulic. The present invention can also be applied to the case where the hose 16 is provided in a path from the lower part of the boom foot to the rear curved part 16c without passing through the swing bracket 10.

It is a fragmentary perspective view of the boom concerning the embodiment of the present invention. It is a side view which shows the attachment state of the boom. It is a partially expanded sectional view which shows the relationship between the boom foot and the hydraulic hose in the state which fell the boom. FIG. 4 is a view corresponding to FIG. 3 showing the relationship between the boom foot and the hydraulic hose when the boom is raised. It is the VV sectional view taken on the line of FIG. FIG. 5 is a view corresponding to FIG. 4 showing another embodiment of the present invention. It is a schematic side view of the whole hydraulic excavator. It is a disassembled perspective view which shows the boom attachment part of a hydraulic shovel. FIG. 3 is a view corresponding to FIG. 2 showing a boom attachment state and a relationship between a conventional boom foot and a hydraulic hose.

DESCRIPTION OF SYMBOLS 2 Upper revolving body 10 Swing bracket 13 Boom foot pin 17 Boom 19 Boom foot 16 Hydraulic hose 16c Backward curved part of hydraulic hose 16d Downward curved part 20 Guide recessed part

Claims (1)

The swing bracket is attached to the upper swing body of the base machine so as to be rotatable about the vertical axis, the boom foot is attached to the swing bracket so as to be rotatable about a horizontal boom foot pin, and the hydraulic hose is in the piping structure of the hydraulic excavator provided with the swing bracket from the base end side below the street boom foot in a path around to the boom back side curved rearward, the guide recesses in the central portion of the boom width direction of the boom foot, The hydraulic hose is provided along the rear curved portion of the hydraulic hose in a state where the boom is tilted, and the hydraulic hose is continuously bent below the rear curved portion and below the boom foot. With the upper part of the boom fitted into the guide recess and along the boom foot. Piping structure of a hydraulic excavator, characterized in that through the boom back side from.

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