JP2020051047A - Construction machine - Google Patents

Abstract

To provide a construction machine capable of preventing damage of a hydraulic pipeline itself or a connection bolt fastening the hydraulic pipeline, or damage of a hydraulic hose connecting the hydraulic pipelines to each other when vibration or deflection is generated on a boom.SOLUTION: Provided is a construction machine in which a steel-pipe hydraulic pipeline 15 is arranged along a boom 6 of a hydraulic shovel 1, and a bucket 8 is activated by circulating hydraulic oil. At a bend part 6a of the boom 6, a pair of connection bolts 19 are arranged while penetrating a clamping member 18 clamping the hydraulic pipeline 15, and double nuts 21 are screwed by inserting tips into bolt holes 16a of a securing base 16 welded on the bend part 6a. A first compression spring 22 is interposed between the securing base 16 and the clamping member 18 in a state of being wound around the connection bolt 19. Deflection of the first spring 22 allows position displacement when the bend part 6a is deflected due to load during drilling and the position displacement in an approaching direction is generated with respect to the clamping member 18.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a construction machine, and more particularly, to a structure for fixing hydraulic piping.

  For example, a hydraulic shovel, which is one type of this type of construction equipment, is provided with an upper revolving structure that can be swiveled on a lower traveling structure equipped with crawlers, and an articulated work front together with a cab and the like on the upper revolving structure. Provided. The work front is composed of a boom, an arm and a bucket, and the excavation work is made possible by changing the angle of each with a hydraulic cylinder. A hydraulic pipe made of steel pipe is arranged on the work front along the boom and the arm, and hydraulic oil is circulated between the hydraulic pump on the upper swing body side and each hydraulic cylinder on the work front via the hydraulic pipe. The hydraulic cylinder operates.

During operation of the hydraulic excavator, vibrations and loads generated due to excavation act on the work front. The above-mentioned hydraulic piping is fastened to a boom or an arm on a work front by a connecting bolt. Therefore, the hydraulic piping receives vibrations from the boom and the arm via the connecting bolt, and receives an external force due to bending of the boom and the arm under load.
In particular, the boom has a shape having a curved portion at an intermediate position in the longitudinal direction, and although the hydraulic piping is curved and formed in advance in accordance with the curved portion, it is practically difficult to accurately form the curvature following the curved portion, There is a tendency for the boom to be fastened somewhat with connecting bolts. For this reason, even in normal times, a load is applied to the connecting bolt, and if an external force due to vibration or deflection is transmitted from the boom, the connecting bolt may not be able to withstand and loosen or break was there.

  As a countermeasure against such a problem, for example, Patent Literature 1 proposes a technique using a compression spring. The bracket and the holding piece welded on the boom are connected via a connecting bolt and a double nut so as to be displaceable in the axial direction, and a compression spring is interposed between the bracket and the double nut, and the urging force is applied. Accordingly, the hydraulic piping is held with elasticity. When vibration or bending occurs in the boom, the compression spring bends to reduce the clamping force on the hydraulic piping, thereby protecting the piping and the connecting bolt.

Japanese Utility Model Publication No. 3-29790

However, when the clamping force on the hydraulic piping is weakened as in the technique of Patent Document 1, a new problem described below occurs.
In order to allow the work front to bend, a plurality of hydraulic pipes are connected via hydraulic hoses as appropriate from the upper swing body to the bucket via the boom and the arm. For this reason, when the holding force between the bracket and the holding piece is weakened and the hydraulic piping is displaced in the longitudinal direction, an unreasonable force is applied to the hydraulic hose, causing a problem that the bolt or the like is damaged.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a hydraulic pipe itself or a connecting bolt for fastening a hydraulic pipe when vibration or bending occurs in the boom. It is an object of the present invention to provide a construction machine capable of preventing breakage or breakage of hydraulic hoses connecting hydraulic pipes.

  In order to achieve the above object, a construction machine of the present invention supports a hydraulic working tool to a body via a boom and an arm, and arranges a steel pipe hydraulic pipe along the boom, and In a construction machine that operates the hydraulic working tool by circulating hydraulic oil through the hydraulic pipe between the hydraulic working tool and the hydraulic working tool, an operating space is formed between the hydraulic working tool and the boom, and the working space is fixed on the boom. The hydraulic pipe is clamped by the clamp member by a fastening force between a fixed base and a bolt hole inserted through the clamp member from one side, and a nut screwed from the other side, and the tip is fixed. A connection bolt inserted into a bolt hole penetrating through the base and projected into the working space, and engaged with a tip of the connection bolt in the working space of the fixed base; A retaining member for connecting the clamp member so as to be displaceable in the contacting and separating directions, and a biasing force in the separating direction interposed between the fixed base and the clamp member while being wound around the connecting bolt. And a first compression spring acting on the first compression spring.

  ADVANTAGE OF THE INVENTION According to the construction machine of this invention, when a vibration or bending arises in a boom, damage of the hydraulic piping itself, the connection bolt which is fastening the hydraulic piping, or damage of the hydraulic hose which connects the hydraulic piping is performed. It can be prevented beforehand.

It is a side view showing the hydraulic shovel of an embodiment. It is a perspective view which shows the fixing structure of the hydraulic piping in a bending part. FIG. 4 is an exploded perspective view showing a fixing structure of a hydraulic pipe in a bending portion. FIG. 3 is a view as viewed in the direction of the arrow A in FIG. 2, showing a fixing structure of a hydraulic pipe in a bending portion. FIG. 5 is a view corresponding to FIG. 4 when the boom is bent by a load. FIG. 11 is a diagram corresponding to FIG. 4 showing another example in which positional displacement in the separating direction is also allowed.

Hereinafter, an embodiment in which the present invention is embodied in a hydraulic excavator will be described.
FIG. 1 is a side view showing a hydraulic shovel of the present embodiment. First, a schematic configuration of the hydraulic shovel will be described with reference to FIG. In the following description, the front, rear, left, right, and up and down directions are mainly expressed by an operator who is mounted on the excavator.

A crawler 3 is provided on the lower traveling body 2 of the excavator 1, and the crawler 3 is driven by a traveling hydraulic motor (not shown) to cause the excavator 1 to travel. An upper swing body 4 (corresponding to the airframe of the present invention) is provided on the lower traveling body 2, and the upper swing body 4 is driven by a turning hydraulic motor (not shown) to turn. An articulated work front 5 is provided at the front of the upper revolving unit 4, and the work front 5 includes a boom 6, an arm 7, and a bucket 8 (corresponding to a hydraulic work tool of the present invention). The angle of the boom 6 is changed by the boom cylinder 6c (corresponding to the tilting operation of the present invention), the angle of the arm 7 is changed by the arm cylinder 7c, and the angle of the bucket 8 is changed by the bucket cylinder 8c.
When the bucket 8 is replaced with a hydraulic breaker or a hydraulic crusher, the replaced device functions as the hydraulic working tool of the present invention.

  An operator's cab 10 on which an operator rides is provided at a front portion of the upper revolving unit 4 on the frame 9, and a fuel tank 11, a machine room 12, a counterweight 13, and the like are provided at a rear side of the operator's cab 10 on the frame 9. Have been. Although not shown, a hydraulic pump driven by an engine is mounted in the machine room 12. The hydraulic pump includes a hydraulic piping for the traveling and turning hydraulic motors and the cylinders 6 c to 8 c of the work front 5. The hydraulic oil is circulated through the hydraulic system to operate these hydraulic devices.

  Each of the cylinders 6c to 8c of the work front 5 circulates hydraulic oil with a hydraulic pump through a steel pipe hydraulic pipe disposed along the boom 6 and the arm 7, and the hydraulic pipe is bolted. It is connected to the boom 6 and the arm 7. For this reason, as described in [Background Art], vibrations caused by excavation are transmitted to the hydraulic piping via bolts, and an external force due to bending of the loaded boom or arm acts on the hydraulic piping. In the countermeasure of Patent Document 1 in which the hydraulic pipe is held by the elasticity of the compression spring, the compression spring is bent in accordance with the vibration or bending of the boom to weaken the holding force on the hydraulic pipe. There is another problem that the hydraulic hose is damaged due to displacement.

In view of such a problem, in the present embodiment, measures are taken to allow the displacement of the hydraulic piping without weakening the clamping force, and the details will be described below.
The hydraulic pipe fixing structure of the present embodiment is applied to the boom 6 of the work front 5. Specifically, as shown in FIG. 1, the boom 6 has a curved portion 6a that is gently curved at the center in the longitudinal direction (front-rear direction), and linear portions 6b formed on both sides of the curved portion 6a. This is embodied as a structure for fixing the hydraulic pipe 15 to the curved portion 6a. The bending portion 6a has a larger deflection due to vibration and load than the straight portion 6b, and the adverse effect is large.

  Basically, the hydraulic piping 15 is disposed along the upper surface of the boom 6 and the region of the straight portion 6b is linear, while the region along the curved portion 6a has the same curvature in advance. It is curved. Although not shown, one end of the hydraulic pipe 15 is connected to the hydraulic pipe on the upper swing body 4 via a hydraulic hose, and the other end of the hydraulic pipe 15 is connected to the hydraulic pipe on the arm 7 via a hydraulic hose. Connected. Thereby, the angle change of the boom 6 with respect to the upper swing body 4 and the angle change of the arm 7 with respect to the boom 6 are allowed.

  The hydraulic piping 15 is connected by bolts at predetermined intervals in the longitudinal direction of the boom 6, and each fixed position B at the linear portion 6b is not described in detail, but the hydraulic piping 15 is simply positioned by bolts. A fixed structure fixed so as not to be displaced is employed. On the other hand, each fixing position A of the bending portion 6a has the following fixing structure in order to allow displacement of the hydraulic pipe 15.

  FIG. 2 is a perspective view showing a fixing structure of the hydraulic pipe 15 in the bending section 6a, FIG. 3 is an exploded perspective view showing a fixing structure of the hydraulic pipe 15 in the bending section 6a, and FIG. 2 is a view showing the fixing structure, and FIG. 5 is a view corresponding to FIG. 4 when the boom 6 is bent by a load.

  As shown in FIG. 1, the hydraulic pipe 15 is connected at three fixed positions A at the bending portion 6a of the boom 6, and the fixed structure shown in FIGS. A fixed base 16 made of a steel plate having a downwardly concave shape by bending is welded onto the curved portion 6a, and an operation space 17 is formed in the fixed base 16. The hydraulic piping 15 is disposed directly above the fixed base 16, and as shown in FIGS. 2 and 3, the hydraulic piping 15 is included from above and below by an arc-shaped holding surface 18 a of a pair of clamp members 18. .

  A flat fastening surface 18b is formed adjacent to the clamping surface 18a of each clamp member 18, and a pair of bolt holes 18c is formed therethrough. The fastening surfaces 18b are overlapped with each other and connected to the bolt holes 18c from above. Bolt 19 is inserted. Screw portions 19a and 19b are formed near the head and at the tip of each connection bolt 19, respectively, and a nut 20 is screwed into the screw portion 19a near the head from below. As a result, the fastening surfaces 18b of the clamp members 18 are fastened, and the holding surfaces 18a of the clamp members 18 hold the hydraulic pipe 15 from above and below by the fastening force.

  The distal end of each connection bolt 19 is inserted into a pair of bolt holes 16a penetrating through the fixed base 16 and protrudes into the working space 17, and the screw portion 19b at the distal end has a double nut 21 (a retaining member according to the present invention). Equivalent) is screwed. As a result, the detachment of the connection bolt 19 upward from the bolt hole 16 a of the fixed base 16 is restricted by the double nut 21, and the contact and separation of the clamp member 18 with respect to the fixed base 16 within the length of the connection bolt 19. Position displacement in the direction is allowed.

  A first compression spring 22 is interposed between the fixed base 16 and the clamp member 18 while being wound around each connection bolt 19. The biasing force of the first compression spring 22 acts in a direction to separate the clamp member 18 from the fixed base 16, and the double nut 21 contacts the lower surface of the fixed base 16. In this state, while the clamp member 18 is further restricted from being separated from the fixed base 16, the clamp member 18 is allowed to approach the fixed base 16 while bending the first compression spring 22.

Next, the operation of the structure for fixing the hydraulic pipe 15 in the hydraulic shovel 1 configured as described above will be described.
During the operation of the excavator 1, the boom 6 receives loads associated with excavation from various directions, but mainly due to the weight of the arm 7 and the bucket 8 and the weight of the excavated material in the bucket 8. There are many opportunities to receive loads. At this time, the boom 6 bends in a direction to increase the curvature of the bending portion 6a (a direction in which the bending is strengthened), and as a result, a relative positional displacement occurs between the bending portion 6a and the clamp member 18 in the approaching direction. In view of the above points, it can be understood that it is more important to take measures to allow the positional displacement in the approaching direction than the positional displacement in the separating direction between the bending portion 6a of the boom 6 and the clamp member 18 (and the hydraulic pipe 15). .

  In the fixing structure of the hydraulic pipe 15 of the present embodiment, when the bending portion 6a of the boom 6 is bent in a direction of increasing the curvature and displaced in a direction approaching the hydraulic pipe 15 from the state shown in FIG. As described above, the position displacement is allowed while the first compression spring 22 is flexed. As a result, although the bending portion 6a is bent, a large external force due to the bending does not act on the clamp member 18, and the clamp member 18 receives only a light repulsive force accompanying the bending of the first compression spring 22. . For this reason, a large external force does not act on the hydraulic pipe 15 held between the clamp members 18, and the breakage thereof can be prevented.

  Further, the positional displacement that occurs between the bending portion 6a of the boom 6 and the clamp member 18 is not limited to the approach direction as described above. Depending on the direction in which the load acts on the work front 5, a positional displacement in the front-rear direction (longitudinal direction of the hydraulic pipe 15) orthogonal to the approaching direction or a positional displacement in the left-right direction also occurs. In the fixing structure of the present embodiment, the inclination of the connection bolt 19 is allowed by bending the first compression spring 22. That is, even when positional displacement occurs not only in the approaching direction but also in the front-rear direction and the left-right direction, since such positional displacement is allowed, it is possible to reduce the external force on the hydraulic pipe 15 and prevent damage beforehand. it can.

  Furthermore, the positional displacement in various directions between the curved portion 6a and the clamp member 18 is allowed, so that the external force applied to the connecting bolt 19 connecting the clamp member 18 to the fixed base 16 is reduced. Means For this reason, breakage of each connection bolt 19 due to excessive external force can be prevented.

  On the other hand, although the clamp member 18 is allowed to be displaced in the front-rear direction due to the inclination of the connecting bolt 19, the permissible width is smaller than that in the left-right direction. This is because the pair of connecting bolts 19 are arranged side by side in the front-rear direction. In the position displacement in the front-rear direction as compared with the position displacement in the left-right direction, the position displacement occurs at an early point when the connecting bolt 19 is tilted to some extent. Be regulated. Further, unlike the technique of Patent Document 1, the hydraulic pipe 15 is firmly held by the connection bolt 19 and the nut 20 with respect to the clamp member 18.

  When a positional displacement in the front-rear direction occurs between the bending portion 6a and the clamp member 18 due to these factors, the positional displacement is allowed to some extent to prevent the hydraulic pipe 15 and the connecting bolt 19 from being damaged as described above. Is done. In addition, by restricting excessive displacement in the front-rear direction, another effect that the breakage of the hydraulic hoses connected to both ends of the hydraulic pipe 15 can be reliably prevented can be achieved.

  The above description relates to a case where a displacement occurs between the bending member 6a of the boom 6 and the clamp member 18 due to the bending of the bending portion 6a. The same effect is exerted on this, and it is possible to prevent the hydraulic piping 15, the connecting bolt 19 or the hydraulic hose from being damaged.

  On the other hand, with respect to the fixing structure of the hydraulic pipe 15 at each fixed position A in the curved portion 6a, the hydraulic pipe 15 is fastened by a bolt at the fixed position B of the straight portion 6b so as not to be displaced. One of the reasons is that the hydraulic pipe 15 is easily tightened because the vibration and deflection are smaller in the straight section 6b than in the curved section 6a and there is no difference in shape from the hydraulic pipe 15 as a result. This is because the possibility of breakage of the hydraulic piping 15 and the connecting bolt 19 is significantly low.

  Also, as a second reason, if the same fixed structure is adopted in the straight portion 6b as well as the curved portion 6a to allow positional displacement, the position of the hydraulic pipe 15 over the entire boom 6 will not be determined, This is because the hydraulic pipe 15, the connecting bolt 19, or the hydraulic hose may be easily damaged. Since the displacement of the hydraulic pipe 15 is restricted by the straight portions 6b on both sides, the effect of preventing the breakage by allowing the displacement of the bending portion 6a is reliably obtained.

  However, the second reason is established in the boom 6 of the excavator 1 of the present embodiment, but is not necessarily established in all excavators. Therefore, the same hydraulic pipe 15 fixing structure as that of the curved portion 6a may be applied to the straight portion 6b of the boom 6.

  The description of the embodiment is finished above, but aspects of the present invention are not limited to this embodiment. For example, in the above-described embodiment, the hydraulic pipe 15 is fixed to the boom 6 of the hydraulic excavator 1. However, the type of the construction machine is not limited to this, and may be applied to, for example, a wheel loader.

  Further, in the above embodiment, the positional displacement in the approaching direction between the fixed base 16 and the clamp member 18 on the curved portion 6a is allowed, but in addition, the positional displacement in the separating direction may be allowed. In this case, as shown in FIG. 8, a second compression spring 31 may be interposed between the lower surface of the fixed base 16 and the double nut 21 in a state wound around each connection bolt 19. Since the displacement of the second compression spring 31 is allowed in the separation direction due to the bending of the second compression spring 31, the effect of preventing damage is obtained even when the displacement of the position in this direction occurs.

In the above-described embodiment, the fixed base 16 on the curved portion 6a and the clamp member 18 are connected via the pair of connection bolts 19, but the present invention is not limited to this. Is also good.
In the above embodiment, the double nut 21 is used as the retaining member, but the present invention is not limited to this. For example, a pin may be fixedly penetrated to the tip of the connection bolt 19, and the protrusion at both ends may restrict upward removal from the bolt hole 16a.

1 Hydraulic excavator (construction equipment)
4 Upper revolving superstructure (airframe)
6 Boom 6a Bending part 8 Bucket (hydraulic work implement)
8c Bucket cylinder 15 Hydraulic piping 16 Fixed base 16a Bolt hole 17 Working space 18 Clamp member 18c Bolt hole 19 Connecting bolt 20 Nut 21 Double nut (Prevention member)
22 first compression spring 31 second compression spring

Claims (4)

A hydraulic working tool is supported on the body via a boom and an arm, and a hydraulic pipe made of steel pipe is arranged along the boom, and the hydraulic working tool is operated between the machine side and the hydraulic working tool via the hydraulic pipe. In a construction machine that operates the hydraulic working tool by circulating oil,
A fixed base fixed to the boom by forming an operation space between the boom and the base;
The hydraulic pipe is clamped by the clamp member by a fastening force with a nut screwed from one side into a bolt hole penetrated through the clamp member, and a tip is penetrated through the fixed base. A connection bolt inserted into the bolt hole and projected into the working space;
A retaining member that engages with the distal end of the connection bolt in the working space of the fixed base and connects the clamp member to the fixed base so that the clamp member can be displaced in the contact / separation direction;
A first compression spring that is interposed between the fixed base and the clamp member while being wound around the connection bolt, and that applies a biasing force in a separating direction. . A second compression spring that is interposed between the fixed base and the retaining member in a state wound around the connection bolt in the operation space, and applies a biasing force in a separating direction. The construction machine according to claim 1, wherein: The boom has a curved portion that is curved at any part in the longitudinal direction,
The construction machine according to claim 1, wherein the fixed base is fixed on a curved portion of the boom. 2. The construction according to claim 1, wherein the fixed base and the clamp member are connected so as to be displaceable in a contact / separation direction by a pair of the connection bolts juxtaposed in a longitudinal direction of the boom. 3. machine.

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