JP2017227249A - Cylinder protection structure and working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylinder protection structure which inhibits a cover member from interfering with a member attached to an outer periphery of a cylinder tube without increasing the number of components.SOLUTION: A boom cylinder 7 includes a cylinder tube 71, a rod 73, and a protection cover 8. The protection cover 8 includes a first cover 81 and a second cover 83. The first cover 81 is longer than the second cover 83 in an axial direction and has a first protection plate 811 and a first attachment plate 813. The second cover 83 is disposed in a space between the first cover 81 and a fixing member. When the boom cylinder 7 extends to its maximum length, the first cover 81 and the second cover 83 continue to cover the rod. When the boom cylinder 7 contracts to its minimum length, one part of the second cover 83 protrudes further to a tip side of the cylinder than the first cover 81 and the first cover 83 overlaps with the other part of the second cover 83.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a protection structure for a cylinder and a technology related to the structure.

  2. Description of the Related Art Conventionally, in a working machine, a cover is provided on a hydraulic cylinder to prevent earth and sand or rocks from colliding with a rod portion. For example, in patent document 1, the boom cylinder (3) provided with the protection apparatus (2) for rods is disclosed.

  Specifically, an outer rail cover (32) and an inner rail cover (35) divided into two parts are provided as protective covers for the rod (29). When the boom cylinder (3) is extended, the two rail covers (32, 35) are connected to each other to be in an extended state. On the other hand, when the boom cylinder (3) is reduced, the inner rail cover (35) is 32) It will be in an accommodation state. Here, the inner rail cover (35) is connected to the cylinder via a support member (36) and a slider (38). According to this invention, it can prevent that a cover interferes with the member provided in the outer periphery of the cylinder cylinder of a hydraulic cylinder.

Japanese Patent No. 3587597

  However, the split type cover described in Patent Document 1 requires a large number of parts such as the support member (36) and the slider (38), so that the configuration of the entire cylinder device is complicated and the work efficiency during assembly is reduced. .

  Therefore, an object of the present invention is to provide a cylinder protection structure that suppresses interference of a cover member with a member attached to the outer periphery of a cylinder tube without increasing the number of parts.

  In order to achieve the above object, the present invention is a cylinder protection structure comprising a cylinder tube and a rod projecting from the tip of the cylinder tube so as to extend and contract, and one end side is fixed to the tip of the rod. On the other hand, a first cover that extends substantially parallel to the axial direction of the cylinder from the one end side and is not fixed to the other end side located on the cylinder tube side, and shorter than the first cover in the axial direction, A second cover fixed to the rod side, and the first cover is supported so as to be slidable in the axial direction with respect to the second cover in accordance with the expansion and contraction of the rod. When extending, the first cover is disposed closer to the tip of the rod than the second cover, and the tip of the rod extends from the cylinder tube side of the rod. The second cover and the first cover continuously cover the rod, and when the cylinder is fully contracted, a part of the second cover is more distal than the first cover than the first cover. And a protective structure for the cylinder, wherein the first cover and the remaining portion of the second cover overlap each other.

  The first cover includes a first protective plate extending in the axial direction, a pair of first legs bent substantially perpendicularly from both end portions in the width direction of the first protective plate, and the one end side A first mounting plate that constitutes a part and is provided with a gap in a direction perpendicular to the surface of the first protection plate and fixed to a tip end portion of the rod by a fixing member, and the second cover Has a second protection plate that protects the rod, and a pair of second legs bent substantially perpendicularly from both ends in the width direction of the second protection plate, and the pair of first legs Has a length that allows the second cover to be disposed inside the first cover, and the pair of second legs includes the second protective plate between the first protective plate and the fixing member. A space that can be disposed, and a space through which the second cover can pass is formed between the first protection plate and the fixing member. Preferably it is.

  The first cover further includes a pair of fixing plates fixed to the first mounting plate, and the pair of fixing plates are the first protection plates of the pair of first legs. It is preferable that the first protective plate is bent substantially perpendicularly from each of the ends opposite to the side connected to the first protective plate.

  Further, the present invention is a work machine, comprising a machine main body and an attachment connected to the machine main body, the attachment includes a cylinder tube and a rod projecting from the tip of the cylinder tube so as to extend and contract, A first cover whose one end is fixed to the tip of the rod, and which extends substantially parallel to the axial direction of the cylinder from the one end and is not fixed to the other end located on the cylinder tube side; A second cover that is shorter than the first cover and is fixed to the rod side of the cylinder tube, the first cover extending in the axial direction with respect to the second cover according to expansion and contraction of the rod. The first cover is disposed closer to the distal end side of the rod than the second cover when the cylinder is fully extended. The second cover and the first cover continuously cover the rod from the cylinder tube side of the cylinder toward the tip of the rod, and when the cylinder is fully contracted, a part of the second cover is There is further provided a work machine characterized in that the first cover and the remaining part of the second cover overlap with each other while projecting to the tip end side of the cylinder from the first cover.

  According to the present invention, when the cylinder is fully contracted, a part of the second cover protrudes more toward the tip side of the cylinder than the first cover, and the first cover overlaps the remaining part of the second cover. Therefore, the first cover can be shortened, and the first cover can be prevented from interfering with the attached member attached to the outer periphery of the cylinder tube. Further, since the second cover is directly attached to the cylinder tube, it is possible to suppress an increase in the number of parts.

1 is a side view showing a hydraulic excavator according to an embodiment of the present invention. The perspective view which shows a part of attachment of a hydraulic excavator. The perspective view (A) which looked at the 1st cover and the 2nd cover from the upper left side, and the perspective view (B) which looked from the lower left side. IV-IV position sectional drawing of FIG. 3 (A). VV position sectional drawing of FIG. 3 (A). The perspective view which shows a part of cylinder with which the protective cover was attached. The top view (A) and side view (B) which show the boom cylinder and protective cover in the most extended state. The top view (A) and side view (B) which expanded the protective cover part among FIG. The top view (A) and side view (B) which show the boom cylinder and protective cover in the most contracted state. The top view (A) and side view (B) which expanded the protective cover part among FIG. XI arrow line view of FIG. 9 (B). The figure which shows the shape of the 1st cover which concerns on a modification.

<1. Configuration>
A cylinder protection structure and a working machine according to an embodiment of the present invention will be described with reference to FIGS. Hereinafter, a hydraulic excavator 1 will be described as an example of a work machine according to the present invention.

  As shown in FIG. 1, the excavator 1 includes a crawler type lower traveling body 2 and an upper swing body 3.

  The upper swing body 3 is mounted on the lower travel body 2 and can swing around the vertical axis with respect to the lower travel body 2. The upper swing body 3 includes a machine main body 4 and an attachment 5 connected to the machine main body 4.

  As shown in FIG. 1, the attachment 5 includes a boom 51, an arm 53, a bucket 55, and the like, and is used by being attached to the machine body 4. As shown in FIG. 2, a pair of boom cylinders 7 for raising and lowering the boom 51 are attached to the boom 51 on the left and right sides of the boom 51. The pair of boom cylinders 7 is an example of a cylinder according to the present invention, and each has the same configuration.

  The boom cylinder 7 includes a cylinder tube 71 and a rod 73 that protrudes from a head cover 71H provided at the tip of the cylinder tube 71 so as to extend and contract. On the base end side of the cylinder tube 71, a member to be attached 75 such as a hose or an oil tightness holding function valve (holding valve) is attached.

  In addition, the boom cylinder 7 is provided with a protective cover 8 that protects the rod 73 from earth and sand and rocks scattered during excavation work and the like.

  As shown in FIG. 3, the protective cover 8 includes a first cover 81 and a second cover 83 that is shorter than the first cover 81 in the axial direction D1 of the cylinder.

  As shown in FIG. 4, the first cover 81 includes a first protection plate 811, a pair of first leg portions 815, a pair of fixing plates 817, and a first attachment plate 813.

  As shown in FIG. 3, the first protective plate 811 is a plate-like member that is long in the axial direction D1. The first protective plate 811 is provided with a pair of first leg portions 815 bent substantially at right angles from both ends in the width direction D2 (direction perpendicular to the axial direction D1) (FIG. 4).

  In addition, a pair of fixing plates 817 that are bent inward at substantially right angles to the pair of first leg portions 815 at the ends of the pair of first leg portions 815 that are not connected to the first protection plate 811. Is further provided.

  The first protective plate 811, the pair of first leg portions 815, and the pair of fixing plates 817 ensure an internal space inside the first cover.

  The first mounting plate 813 is a plate member having sufficient strength and thickness to support the first protective plate 811. The length of the first mounting plate 813 in the width direction D2 (direction orthogonal to the axial direction D1) is substantially the same as the width of the upper surface portion of the first protective plate 811.

  Specifically, the first mounting plate 813 constitutes a part of the first cover 81 on the rod side, and is disposed with a gap in a direction perpendicular to the surface of the first protective plate 811. The first mounting plate 813 is formed with a through hole 813 h for fixing the first cover 81 to the tip of the rod 73 with a fixing member 9 (screw or the like).

  As shown in FIGS. 3 and 4, the portion of the fixing plate 817 that contacts the first mounting plate 813 is fixed by welding or the like.

  As shown in FIGS. 3 and 5, the second cover 83 includes a second protective plate 831, a second attachment member 833, and a pair of second leg portions 835.

  As shown in FIG. 3, the length of the second protective plate 831 in the axial direction D1 is shorter than the length of the first protective plate 811 in the axial direction D1.

  As shown in FIG. 5, the second protective plate 831 is provided with a pair of second leg portions 835 bent substantially at right angles from both ends in the width direction D2 (direction perpendicular to the axial direction D1). The second protective plate 831 and the pair of second legs 835 have a substantially U-shaped cross section to secure an internal space inside the second cover 83.

  Further, the width (D2 direction) of the second protective plate 831 is slightly shorter than the width of the first protective plate 811. Further, the height (D3 direction) of the second leg portion 835 is slightly shorter than the height of the first leg portion 815. This is because the second cover 83 is disposed inside the first cover 81 when the protective cover 8 is attached.

  As shown in FIG. 3 (B), the second mounting member 833 has a second center at the one end side in the axial direction D1 in the center of the back surface of the second protective plate 831 (that is, the inside of the substantially U-shaped space). The protective plate 831 is erected.

  The protective cover 8 as described above is provided along the axial direction D1 of the boom cylinder 7. Specifically, as shown in FIG. 6, the first mounting plate 813 is fixed to the tip of the rod 73 by the fixing member 9. On the other hand, the second mounting member 833 of the second cover 83 is fixed to the rod 73 side tip of the cylinder tube 71 (specifically, the outer periphery of the head cover 71H).

  The first cover 81 and the second cover 83 are arranged on a straight line in the axial direction D1. Then, according to the expansion and contraction of the boom cylinder 7, the first cover 81 slides (slides) in the axial direction D <b> 1 and overlaps (wraps) all or part of the second cover 83.

  Next, the state of the protective cover 8 attached to the boom cylinder 7 in the most extended state will be described with reference to FIGS. 7 and 8.

  As shown in FIG. 7, the first cover 81 is disposed closer to the distal end side of the rod 73 than the second cover 83 when the boom cylinder 7 is fully extended. Accordingly, the second cover 83 and the first cover 81 continuously cover the rod 73 from the cylinder tube 71 side toward the distal end portion 73 </ b> A of the rod 73.

  However, as shown in FIG. 8B, a part of the contraction side C2 of the first protection plate 811 and a part of the extension side C1 of the second protection plate 831 overlap each other by a distance d1. That is, a part of the extension side C1 of the second protective plate 831 is inserted inside the first cover 81 described above. For this reason, even when the boom cylinder 7 is fully extended, the first cover 81 and the second cover 83 are not detached, and the state where the protective surface is continuous is maintained.

  When the boom cylinder 7 gradually contracts from the most extended state shown in FIG. 7, the rod 73 is stored in the cylinder tube 71 (that is, the rod 73 moves to the contraction side C2). The second cover 83 does not move because it is fixed to the cylinder tube 71, but the first cover 81 attached to the tip 73A of the rod 73 moves to the contraction side C2 together with the rod 73.

  Thereafter, the first cover 81 shifts to a state where it is superimposed on the second cover 83, and the second cover 83 is hidden by the first cover 81 until the boom cylinder 7 is fully retracted.

  As shown in FIG. 11, the first cover 81 includes the second protection plate 831 and the second leg portion 835 of the second cover 83 in the space formed by the first protection plate 811, the first leg portion 815, and the fixing plate 817. It slides to the contraction side C2 while enclosing it. Finally, the boom cylinder 7 shifts to the most contracted state shown in FIG. When the boom cylinder 7 is fully contracted, most of the rod 73 is stored in the cylinder tube 71.

  Next, the state of the protective cover 8 attached to the boom cylinder 7 in the most contracted state will be described with reference to FIGS. 9 and 10.

  As shown in FIG. 9, when the boom cylinder 7 is fully contracted, a part of the second cover 83 protrudes further toward the distal end side of the boom cylinder 7 than the first cover 81. Further, the remaining portion (the portion that does not protrude) of the second cover 83 overlaps the first cover 81.

  More specifically, the first cover 81 slides to the contraction side C2 as much as possible and stops while enclosing the second protective plate 831 of the second cover 83 in the contraction process. Then, a part of the tip side of the rod 73 of the second protective plate 831 contained therein protrudes from the internal space of the first cover 81 and the first cover 81 overlaps the remaining portion of the second cover 83. The second cover 83 is disposed in a space between the first protective plate 811 and the upper end portion of the fixing member 9.

<2. Effects of the embodiment>
In the present embodiment, as shown in FIG. 9B, when the boom cylinder 7 is fully contracted, a part of the second cover 83 protrudes further toward the distal end side of the boom cylinder 7 than the first cover 81, and the second The first cover 81 is superimposed on the remaining part of the cover 83. Therefore, the first cover 81 can be shortened, and the first cover 81 is attached to a member 75 to be attached such as a hose or an oil-tight holding function valve (holding valve) attached to the outer periphery of the proximal end of the cylinder tube 71. It is possible to suppress interference.

  Further, since the second cover 83 is directly attached to the cylinder tube 71, an increase in the number of parts can be suppressed.

  In the present embodiment, the first protection plate 811 of the first cover 81 is provided with the first leg portion 815, and the second protection plate 831 of the second cover 83 is also more than the first leg portion 815. A short second leg 835 is provided. Therefore, as shown in FIG. 11, the second cover 83 is inserted inside the first cover 81, and it is possible to suppress backlash between the first cover 81 and the second cover 83.

  In the present embodiment, the first leg 81 and the second leg 835 are configured by bending the first cover 81 and the second cover 83, respectively. Therefore, the strength of each cover is improved. Therefore, even if the protective cover 8 collides with stones or rocks, it becomes difficult to deform.

  In the present embodiment, as shown in FIG. 11, a fixing plate 817 is provided on the first leg 815 of the first cover 81, and the first mounting plate 813 is attached to the fixing plate 817. For this reason, the height of the fixing member 9 that fixes the first mounting plate 813 by the thickness of the fixing plate 817 can be reduced. As a result, a space between the upper end of the fixing member 9 and the first protective plate 811 can be secured. By securing such a space, it is possible to avoid increasing the height of the first cover 81 itself, which is advantageous in terms of weight.

<3. Modification>
The cylinder protection structure according to the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made within the scope described in the claims.

  Specifically, in the above embodiment, when the first cover 81 slides in the axial direction D1, the first cover 81 passes through the outside of the second cover 83 and overlaps with a part or all of the second cover 83. However, the present invention is not limited to this. Conversely, the first cover 81 may pass through the inside of the second cover 83 and overlap with part or all of the second cover 83.

  In this case, if the second attachment member 833 shown in FIG. 3 exists, the first cover 81 cannot pass through the inside of the second cover 83. Therefore, in this modification, a pair of attachment members for connecting the pair of second leg portions 835 and the head cover 71H shown in FIG. 5 are provided without providing the second attachment member 833 shown in FIG. That's fine. Alternatively, the pair of second legs 835 themselves may be extended and connected to the head cover 71H. As a result, the first cover 81 can slide inside the second cover 83.

  Moreover, although the case where the fixing plate 817 was provided in the 1st cover 81 was illustrated in the said embodiment, it is not limited to this. For example, without attaching the fixing plate 817 to the first cover 81, the first mounting plate 813 is directly fixed to each of the ends of the pair of first legs 815 to which the first protective plate 811 is not connected. May be. According to this configuration, the protective cover 8 can have a simpler structure.

  Further, even when the fixing plate 817 is provided on the first cover 81, as shown in FIG. 4, the pair of fixing plates 817 may be bent inside the pair of first legs 815, but is not limited thereto. As shown in FIG. 12, a pair of fixing plates 818 bent outward from the pair of first leg portions 815 may be used. According to such a configuration, the height of the fixing member 9 that fixes the first mounting plate 813 by the thickness of the fixing plate 818 can be reduced as in the above-described embodiment.

  Moreover, in the said embodiment, although the boom cylinder 7 was illustrated as an example of a cylinder, it is not limited to this, It is possible to apply this invention also to the other cylinder with which a working machine is mounted | worn.

  As described above, the configuration according to the present invention is suitable for use in a hydraulic excavator or the like equipped with a hydraulic cylinder having a protective cover.

1 hydraulic excavator, 2 lower traveling body, 3 upper turning body, 4 machine body,
5 Attachment, 7 Boom cylinder, 8 Protective cover, 9 Fixing member,
51 boom, 53 arm, 55 bucket, 71 cylinder tube,
71H head cover, 73 rod, 73A tip, 75 attached member,
81 First cover, 83 Second cover, 813 Mounting plate, 815 First leg,
817 fixing plate, 831 second protection plate, 833 second mounting member, 835 second leg,
C1 expansion side, C2 contraction side, d1 distance, D1 axial direction, D2 width direction

Claims (4)

A cylinder protection structure comprising a cylinder tube and a rod projecting from the tip of the cylinder tube so as to expand and contract,
A first cover whose one end is fixed to the tip of the rod, while extending from the one end substantially parallel to the axial direction of the cylinder and whose other end located on the cylinder tube side is not fixed;
A second cover that is shorter than the first cover in the axial direction and is fixed to the rod side of the cylinder tube;
With
The first cover is supported so as to be slidable in the axial direction with respect to the second cover according to expansion and contraction of the rod,
When the cylinder is fully extended, the first cover is disposed closer to the tip end of the rod than the second cover, and the second cover and the rod extend from the cylinder tube side of the rod toward the tip of the rod. A first cover continuously covers the rod;
When the cylinder is fully contracted, a part of the second cover protrudes more toward the front end side of the cylinder than the first cover, and the first cover and the remaining part of the second cover overlap. Cylinder protection structure. The first cover is
A first protective plate extending in the axial direction;
A pair of first legs bent substantially perpendicularly from both ends in the width direction of the first protective plate;
A first mounting plate that constitutes a part of the one end side, is provided with a gap in a direction perpendicular to the surface of the first protection plate, and is fixed to the tip of the rod by a fixing member;
Have
The second cover is
A second protective plate for protecting the rod;
A pair of second legs bent substantially perpendicularly from both ends in the width direction of the second protective plate;
Have
The pair of first legs have a length that allows the second cover to be disposed inside the first cover;
The pair of second legs have a length that allows the second protective plate to be disposed between the first protective plate and the fixing member,
The cylinder protective structure according to claim 1, wherein a space through which the second cover can pass is formed between the first protection plate and the fixing member. The first cover further includes a pair of fixing plates fixed to the first mounting plate,
The pair of fixing plates are bent substantially perpendicularly from each of the ends of the pair of first legs that are opposite to the side connected to the first protection plate, and are substantially the same as the first protection plate. 3. The protective structure for a cylinder according to claim 1, wherein the protective structure extends in parallel. A working machine,
The machine body,
An attachment connected to the machine body;
With
The attachment is
A cylinder tube;
A rod projecting from the tip of the cylinder tube so as to expand and contract;
A first cover whose one end is fixed to the tip of the rod, while extending from the one end substantially parallel to the axial direction of the cylinder and whose other end located on the cylinder tube side is not fixed;
A second cover that is shorter than the first cover in the axial direction and is fixed to the rod side of the cylinder tube;
With
The first cover is supported so as to be slidable in the axial direction with respect to the second cover according to expansion and contraction of the rod,
When the cylinder is fully extended, the first cover is disposed closer to the tip end of the rod than the second cover, and the second cover and the rod extend from the cylinder tube side of the rod toward the tip of the rod. A first cover continuously covers the rod;
When the cylinder is fully contracted, a part of the second cover protrudes more toward the front end side of the cylinder than the first cover, and the first cover and the remaining part of the second cover overlap. Working machine.

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