JP2012136107A - Truck frame for construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a truck frame for a construction machine in which even if rock or the like collides with a lower step positioned blow an upper step, breakage of bolst for fixing the lower step is prevented.SOLUTION: The truck frame 12 for a hydraulic shovel 1 includes: the upper step 21 and the lower step 22 which are arranged so as to have vertical step difference and which include a mounting part 24b and a mounting part 22c respectively, the mounting part 24b and the mounting part 22c being fixed to a truck frame body 12a by the fastening of bolts 33, 33; 34, 34' respectively. In the truck frame 12, the lower surface of the mounting part 24b of the upper step 21 is brought into contact with the upper surface of the mounting part 22c of the lower step 22.

Description

  The present invention relates to a track frame suitable for use in a construction machine such as a hydraulic excavator.

  For example, a hydraulic excavator includes a lower traveling body having a crawler traveling device. On the lower traveling body, an upper revolving body is installed so as to be able to turn freely. A cab that constitutes a driver's cab is installed in the front left part of the upper swing body. An engine room that is partitioned by a cover such as an engine hood is provided at the rear part of the upper swing body with a counterweight mounted at the rearmost part.

The track frame of the crawler type traveling device is configured by attaching lifting step devices to the front part and the rear part of the track frame main body that extends in the front-rear direction and constitutes the framework of the crawler type traveling device. The lifting and lowering step device is used as a scaffold when an operator gets on and off the cab or when an operator gets on and off the upper swing body for maintenance and inspection.
As for the step for raising and lowering provided in the track frame, it is necessary to provide two steps in which the height is changed in two steps in relation to the installation height of the cab (see, for example, Patent Document 1).

JP 2010-127070 A

  FIG. 8 shows an external perspective view (a) and an enlarged F part view drawing oil of a step device for raising and lowering provided in a conventional track frame.

  8A is provided with an upper step 101 and a lower step 102 that are arranged with a step difference in the vertical direction.

Attachment portions 101 a are provided on both sides of the upper step 101. The mounting portion 101a is provided with two bolt insertion holes with a predetermined interval in the vertical direction.
Similarly, attachment portions 102 a are provided on both sides of the lower step 102. Similarly, the mounting portion 102a is also provided with two bolt insertion holes with a predetermined interval in the vertical direction.

A pair of upper sheet members 104 and 104 corresponding to the attachment portions 101 a and 101 a on both sides of the upper step 101 are welded and fixed to the outer surface of the track frame main body 103.
Similarly, a pair of lower sheet members 105, 105 corresponding to the attachment portions 102 a, 102 a on both sides of the lower step 102 are welded and fixed to the outer surface of the track frame main body 103.
The upper sheet member 104 is formed with female screw portions corresponding to the two bolt insertion holes in the attachment portion 101 a of the upper step 101.
Similarly, the lower sheet member 105 has female screw portions corresponding to the two bolt insertion holes in the attachment portion 102a of the lower step 102.

The upper step 101 is fixed to the track frame main body 103 by tightening upper and lower bolts 106 and 106 that are screwed into the female screw portion of the upper sheet member 104 through the bolt insertion hole of the attachment portion 101a.
Similarly, the lower step 102 is fixed to the track frame main body 103 by tightening bolts 107 and 107 ′ which are screwed into the female screw portion of the lower sheet member 105 through the bolt insertion hole of the attachment portion 102 a.

By the way, the lower step 102 is disposed at a position close to the ground below the upper step 101. For this reason, obstacles often collide with the lower step 102 during construction work.
Obstacles that collide with the lower step 102 are mainly rocks on the ground and flying stones that jumped up from the ground (hereinafter collectively referred to as “rocks”). On the other hand, there are many cases of collision from below or obliquely below. As a result, an external force from a rock or the like is applied to the footrest portion 102b of the lower step 102, and the footrest portion 102b is bent so as to bend upward. When an external force that cannot be suppressed by the deformation of the footrest portion 102b is applied to the footrest portion 102b, the attachment portion 102a of the lower step 102 slips with respect to the lower seat member 105. Then, the attachment portion 102a of the lower step 102 is rotated in the direction of the arrow indicated by the symbol G in FIG. 8B with the upper bolt 107 as a fulcrum. By this rotation, the lower bolt 107 ′ receives a shearing force from the mounting portion 102 a of the lower step 102. Thus, when a strong impact is repeatedly applied to the lower bolt 107 ′ in the shearing direction, the possibility that the bolt 107 ′ is broken is extremely high.

For this reason, the conventional track frame has a problem that when a rock or the like collides with the lower step 102, the lower bolt 107 'for fixing the lower step 102 may be broken.
If the lower bolt 107 ′ is broken, not only can the lower step 102 fall off or the mounting strength is reduced, so that it cannot be used as a scaffold, but it is also difficult to replace the damaged step. Therefore, breakage of the bolt 107 'must be avoided.

  The present invention has been made in view of the above-described problems, and even if a rock or the like collides with a lower step located below the upper step, it is possible to prevent breakage of a bolt that fixes the lower step. An object of the present invention is to provide a truck frame for a construction machine.

In order to achieve the above object, the track frame of the construction machine according to the first invention comprises:
A truck for a construction machine comprising an upper step and a lower step arranged with a step on the upper and lower sides, wherein the upper step mounting portion and the lower step mounting portion are fixed to the track frame body by fastening bolts, respectively. In the frame,
The lower surface of the attachment part of the upper step and the upper surface of the attachment part of the lower step are brought into contact with each other.

Next, the track frame of the construction machine according to the second aspect of the present invention includes an upper step and a lower step arranged with a step difference in the vertical direction, and the attachment portion of the upper step and the attachment portion of the lower step are respectively bolted. In the track frame of the construction machine fixed to the track frame body by
A seat member is provided between the upper step mounting portion and the lower step mounting portion, and the track frame body,
Positioning a part of the sheet member between the upper step mounting portion and the lower step mounting portion,
The lower surface of the mounting portion of the upper step and a part of the sheet member are brought into contact with each other, and the upper surface of the mounting portion of the lower step and a part of the sheet member are brought into contact with each other.

In the first invention or the second invention,
The upper step and the lower step have a footrest portion at the center in the width direction,
In the width direction of the construction machine, it is preferable that the footrest portion of the lower step is positioned outside the footrest portion of the upper step (third invention).

For example, the lower step mounting part located on the lower side of the upper step is fixed to the track frame main body by fastening two upper and lower bolts, and rocks or the like can be seen from below or obliquely below the footrest part of the lower step. Consider the case where an obstacle collides.
In this case, an external force from a rock or the like is applied to the footrest portion of the lower step, and the footrest portion is bent so as to bend upward. When an external force that cannot be suppressed by the deformation of the footrest portion is applied to the footrest portion, the attachment portion of the lower step tries to rotate around the bolt with the upper bolt as a fulcrum.
In the track frame of the construction machine of the first aspect, the lower surface of the upper step mounting portion and the upper surface of the lower step mounting portion are in contact with each other. For this reason, even if the attachment portion of the lower step tries to rotate around the bolt with the upper bolt as a fulcrum, the rotation is blocked by the attachment portion of the upper step. By blocking the rotation of the lower step mounting portion by the upper step mounting portion, the action of the shearing force from the lower step mounting portion to the lower bolt can be suppressed.
Therefore, even if rocks or the like collide with the lower step, there is an effect that it is possible to prevent breakage of the bolt that fixes the lower step.

In the second invention, the seat member is provided between the upper step mounting portion and the lower step mounting portion and the track frame main body. And the lower surface of the attachment part of an upper step and a part of sheet member, and the upper surface of the attachment part of a lower step and a part of sheet member are contacted, respectively. For this reason, even if the attachment part of the lower step tries to rotate around the bolt with the upper bolt as a fulcrum, the rotation is prevented by the attachment part of the upper step through a part of the sheet member. By preventing rotation of the lower step mounting portion with a part of the sheet member interposed by the upper step mounting portion, it is possible to suppress the action of shearing force from the lower step mounting portion to the lower bolt.
Therefore, even if rocks or the like collide with the lower step, there is an effect that it is possible to prevent breakage of the bolt that fixes the lower step.

  In the third invention, the footrest portion of the lower step is positioned outside the footrest portion of the upper step. Thereby, the raising / lowering operation | movement can be performed easily.

1 is an overall perspective view of a hydraulic excavator including a track frame according to an embodiment of the present invention. Part A enlarged view of FIG. B part enlarged view of FIG. C arrow view of FIG. Explanatory drawing of the modification (1) of this embodiment Explanatory drawing of the modification (2) of this embodiment Explanatory drawing of the modification (3) (4) of this embodiment External perspective view of a step device for raising and lowering provided on a conventional track frame (a) and F part enlarged view of (a)

Next, specific embodiments of the track frame of the construction machine according to the present invention will be described with reference to the drawings.
The embodiment described below is an example in which the present invention is applied to a track frame of a crawler type traveling device of a hydraulic excavator (construction machine). However, the present invention is not limited to this, and the present invention can also be applied to a truck frame of a construction machine such as a bulldozer other than a hydraulic excavator. In the following description, the width direction of the hydraulic excavator is assumed to be the width direction of the lower traveling body. Further, the front / rear and left / right directions are made to coincide with the front / rear and left / right directions of the lower traveling body unless otherwise specified.

<General description of hydraulic excavator: See FIG. 1>
A hydraulic excavator 1 shown in FIG. 1 includes a lower traveling body 2 including a crawler traveling device 2a.
An upper swing body 3 is installed on the lower traveling body 2 so as to be freely rotatable.
A work machine 7 having a boom 4, an arm 5, and a bucket 6 rotatably connected to each other is attached to the front center portion of the upper swing body 3 so as to be able to bend up and down.
A cab 8 that constitutes a driver's cab is installed on the front left portion of the upper swing body 3.
An engine room 11 that is partitioned by a cover such as an engine hood 10 is provided at the rear part of the upper swing body 3 with a counterweight 9 mounted at the rearmost part.

<Arrangement and function description of step device for lifting / lowering: see FIG. 1>
The crawler belt type traveling device 2 a includes a track frame 12. The track frame 12 is configured by elevating step devices 20 and 20 ′ attached to the front and rear portions of the track frame main body 12 a that extends in the front-rear direction of the lower traveling body 2 and constitutes the framework of the crawler-type traveling device 2 a. ing. The elevating step devices 20 and 20 ′ are used as a scaffold when an operator gets on and off the cab 8 or when an operator gets on and off the upper swing body 3 for maintenance and inspection.
The elevating step device 20 disposed at the front portion of the track frame main body 12a and the elevating step device 20 'disposed at the rear portion of the track frame main body 12a are basically the same. In the following, as a representative, the lifting and lowering step device 20 disposed at the front portion of the track frame main body 12a will be described.

<Description of schematic configuration of step device for lifting / lowering: see FIG. 2>
The elevating step device 20 shown in FIG. 2 includes an upper step 21 and a lower step 22 that are arranged with steps in the vertical direction.

<Explanation of upper step: See FIGS. 2 and 4>
As shown in FIG. 2, the upper step 21 includes a footrest member 23 that constitutes a footrest portion for placing a foot on the center portion in the width direction when moving up and down. Both ends of the footrest member 23 are supported by support members 24.
The footrest member 23 is formed of a strip-shaped plate member that extends in the front-rear direction with the plate surface facing the left-right direction of the lower traveling body 2. Concavities and convexities 25 are formed on the upper side of the footrest member 23 so as not to slip when the foot is placed.
The support member 24 is formed by subjecting a plate material cut into a predetermined shape to a predetermined bending process. The support member 24 has an arm portion 24a that extends obliquely upward outward from the vicinity of the outer surface of the track frame body 2 with the plate surface facing in the front-rear direction of the lower traveling body 2, and a plate in the left-right direction of the lower traveling body 2. A mounting portion 24b facing the outer surface of the track frame main body 12a with a predetermined interval is provided.
The distal end portion of the arm portion 24a and the end portion of the footrest member 23 are fixed by welding.
The mounting portion 24b is provided with two bolt insertion holes 26 and 26 (see FIG. 4) with a predetermined distance in the vertical direction.

<Explanation of lower steps: see FIGS. 2 and 4>
As shown in FIG. 2, the lower step 22 is formed by subjecting a plate material cut into a predetermined shape to a predetermined bending process. The lower step 22 includes a footrest portion 22a, a support portion 22b, and an attachment portion 22c.
The footrest portion 22a is for putting a foot on when moving up and down, and is composed of a belt-like plate portion extending in the front-rear direction with the plate surface facing the left-right direction of the lower traveling body 2. Concavities and convexities 27 are formed on the upper side portion of the footrest portion 22a so as not to slip when the foot is placed.
The support portion 22b extends straight from the vicinity of the outer surface of the track frame main body 12a with the plate surface in the front-rear direction of the lower traveling body 2, and is connected to the footrest portion 22a via the bent portion 22d. Note that the vertical width of the support portion 22b is larger than the vertical width of the footrest portion 22a, and the strength of the support portion 22b is set higher than the strength of the footrest portion 22a.
The mounting portion 22c faces the outer surface of the track frame main body 12a with a predetermined interval with the plate surface facing in the left-right direction of the lower traveling body 2, and is connected to the support portion 22c via a bent portion 22e. .
The mounting portion 22c is provided with two bolt insertion holes 28 and 28 (see FIG. 4) with a predetermined interval in the vertical direction.

<Explanation of the positional relationship between the upper step and the lower step, as shown in FIG. 4>
As shown in FIG. 4, in the width direction (left-right direction) of the lower traveling body 2, the footrest portion 22 a of the lower step 22 is positioned outside the footrest member 23 that constitutes the footrest portion of the upper step 21. Has been. Thereby, the raising / lowering operation | movement can be performed easily.

<Description of upper sheet member: See FIGS. 2 and 4>
As shown in FIG. 2, an upper sheet member 31 is interposed between the mounting portion 24b of the upper step 21 and the outer surface of the track frame main body 12a. The upper sheet member 31 is made of a block material having a seating surface corresponding to the mounting portion 24b of the upper step 21, and is fixedly welded to the outer surface of the track frame body 12a.
The upper sheet member 31 is formed with female screw portions 31a and 31a corresponding to the two bolt insertion holes 26 and 26 in the mounting portion 24b of the upper step 21 (see FIG. 4).

<Description of lower sheet member: See FIGS. 2 and 4>
As shown in FIG. 2, a lower seat member 32 is interposed between the attachment portion 22c of the lower step 22 and the outer surface of the track frame main body 12a. The lower seat member 32 is made of a block material having a seating surface corresponding to the mounting portion 22c of the lower step 22 and is positioned outside the track frame main body 12a at a height position with a gap between the lower seat member 32 and the upper seat member 31. It is welded to the side.
The lower seat member 32 is formed with female screw portions 32a and 32a corresponding to the two bolt insertion holes 28 and 28 in the attachment portion 22c of the lower step 22 (see FIG. 4).

<Explanation of mounting structure of upper step and lower step: See FIGS. 3 and 4>
As shown in FIG. 4, the upper step 21 is attached to the track frame main body 12a by tightening bolts 33, 33 screwed into the female screw portions 31a, 31a of the upper sheet member 31 through the bolt insertion holes 26, 26 of the mounting portion 24b. Fixed.
Similarly, the lower step 22 is fixed to the track frame main body 12a by tightening bolts 34 and 34 'screwed into the female screw portions 32a and 32a of the lower sheet member 32 through the bolt insertion holes 28 and 28 of the attachment portion 22c.
Here, as shown in FIG. 3, the lower surface of the mounting portion 24 b of the upper step 21 and the upper surface of the mounting portion 22 c of the lower step 22 are completely in contact with each other. In addition, even when the lower surface of the mounting portion 24b of the upper step 21 and the upper surface of the mounting portion 22c of the lower step 22 are brought close to each other with a minute gap, the same effect can be achieved according to the spirit of the present invention. is there. The term “contact” in the present invention encompasses both the concept of “complete contact” and the concept of “proximity with a minute gap”.

<Description of the state when an obstacle collides with the lower step: See FIGS. 2 and 3>
The lower step 22 is arranged at a position close to the ground below the upper step 21. For this reason, during construction work, obstacles such as rocks often collide with the lower step 22.
In many cases, rocks and the like that collide with the lower step 22 collide with the footrest portion 22a of the lower step 22 from below or obliquely below. In this case, an external force from a rock or the like is applied to the footrest portion 22a of the lower step 22, and the footrest portion 22a is bent so as to bend upward. When an external force that cannot be suppressed by the deformation of the footrest portion 22a is applied to the footrest portion 22a, the attachment portion 22c of the lower step 22 is used as a fulcrum and the symbol D in FIG. A rotational force for rotating around the upper bolt 34 in the direction indicated by the arrow acts on the mounting portion 22 c of the lower step 22.

<Description of the effect of this embodiment: See FIG. 2>
In the track frame 12 of the present embodiment, the upper surface of the mounting portion 22 c of the lower step 22 is in contact with the lower surface of the mounting portion 24 b of the upper step 21. As a result, a reaction force that opposes the rotational force can be obtained from the upper step 21. Therefore, even if the mounting portion 22c of the lower step 22 tries to rotate around the upper bolt 34 with the upper bolt 34 as a fulcrum, the rotation is blocked by the mounting portion 24b of the upper step 21. By preventing the attachment portion 22c of the lower step 22 from rotating by the attachment portion 24b of the upper step 21, the action of the shearing force from the attachment portion 22c of the lower step 22 to the lower bolt 34 'can be suppressed.
Therefore, even if rocks or the like collide with the lower step 22, breakage of the bolt 34 ′ that fixes the lower step 22 can be prevented.
It should be noted that if the upper and lower steps 21 and 22 are integrated with each other and manufactured by sheet metal, the yield is deteriorated. By making the upper and lower steps 21 and 22 as separate bodies in order to improve the yield, the strength of the mounting portions 22c and 24b is reduced, but by bringing the upper and lower steps 21 and 22 into contact with each other, the lack of strength can be compensated.

  As mentioned above, although the track frame of the construction machine of the present invention has been described based on one embodiment, the present invention is not limited to the configuration described in the above embodiment, and the configuration is appropriately set within the scope not departing from the gist thereof. Can be changed.

<Description of Modification (1): See FIG. 5>
In the above embodiment, as shown in FIG. 3, the example in which the attachment portion 22 c of the lower step 22 is brought into direct contact with the attachment portion 24 b of the upper step 21 is shown, but the modification example shown in FIG. possible.
That is, in the modification of the above embodiment shown in FIG. 5, instead of the upper sheet member 31 and the lower sheet member 32 in the above embodiment, a sheet in which these sheet members 31 and 32 are integrally coupled. The member 35 is employed. The sheet member 35 includes a sheet member main body 35a and a projection 35b formed at an intermediate position in the vertical direction of the sheet member main body 35a.

<Same as above: See FIG. 5>
The sheet member main body 35a functions as both the upper sheet member 31 and the lower sheet member 32 in the above embodiment. The seat surface corresponds to the mounting portion 24b of the upper step 21, and the mounting portion of the lower step 22 22c, a female screw portion similar to the female screw portion 31a provided on the upper sheet member 31, and a female screw portion similar to the female screw portion 32a provided on the lower sheet member 32. .
The protrusion 35 b has an upper surface portion that can contact the lower surface of the mounting portion 24 b of the upper step 21 and a lower surface portion that can contact the upper surface of the mounting portion 22 c of the lower step 22.
The lower surface of the mounting portion 24b of the upper step 21 is in contact with the upper surface portion of the protrusion 35b, and the upper surface of the mounting portion 22c of the lower step 22 is in contact with the lower surface portion of the protrusion 35b.

<Same as above: See FIG. 5>
Thus, the lower surface of the mounting portion 24b of the upper step 21 and the projection 35b of the sheet member 35 are brought into contact with the upper surface of the mounting portion 22c of the lower step 22 and the projection 35b of the sheet member 35, respectively. Accordingly, a reaction force that opposes the rotational force in the direction of the arrow E in FIG. 5 acting on the attachment portion 22c of the lower step 22 can be obtained from the upper step 21 via the protrusion 35b. Therefore, the same effect as that of the above embodiment can be obtained also by the modification shown in FIG.

<Description of Modification (2): See FIG. 6>
Moreover, in the said embodiment, as shown in FIG. 3, although the example which gives a clearance gap between the upper sheet member 31 and the lower sheet member 32 was shown, as shown in FIG. Instead of the lower sheet member 32 of the embodiment, a lower sheet member 32A that extends upward from the lower sheet member 32 and can be abutted against the lower surface of the upper sheet 31 is adopted, and the lower surface of the upper sheet member 31 and the lower sheet You may make the upper surface of member 32A contact. Further, the upper and lower sheet members 31, 32A may be integrally formed. As a result, the bolt 34 of the lower step 22 can be attached to the upper part, and the moment when the bolt 34 ′ rotates around the bolt 34 by increasing the distance between the bolt 34 and the bolt 34 ′. Will become difficult to rotate. And the rotation prevention of the attachment part 22c of the lower step 22 by the attachment part 24b of the upper step 21 becomes more stable.

<Description of Modified Examples (3) and (4): See FIG. 7>
In the above embodiment, when the attachment portion 22c of the lower step 22 and the attachment portion 24b of the upper step 21 are brought into contact, the upper surface of the attachment portion 22c and the lower surface of the attachment portion 24b are brought into contact with each other as horizontal surfaces. However, the present invention is not limited to this, and there may be modified examples shown in FIGS. 7 (a) and 7 (b).
In the modification shown in FIG. 7A, when the attachment portion 22c of the lower step 22 and the attachment portion 24b of the upper step 21 are brought into contact with each other, the upper surface of the attachment portion 22c and the lower surface of the attachment portion 24b are moved in the vertical direction. Are in contact with each other as inclined surfaces having an inclination.
In the modification shown in FIG. 7B, when the attachment portion 22c of the lower step 22 and the attachment portion 24b of the upper step 21 are brought into contact with each other, the upper surface of the attachment portion 22c and the lower surface of the attachment portion 24b are respectively moved in the vertical direction. As the concavo-convex surface provided with the concavo-convex surface, the concavo-convex portions of each other are brought into contact with each other.

  The track frame of the construction machine according to the present invention has a characteristic that even if a rock or the like collides with the lower step located on the lower side of the upper step, it is possible to prevent breakage of the bolt that fixes the lower step. Therefore, it can be suitably used for a frame of an undercarriage device for a vehicle including a crawler type traveling device as well as a construction machine such as a hydraulic excavator or a bulldozer.

1 Excavator (construction machine)
DESCRIPTION OF SYMBOLS 12 Track frame 12a Track frame main body 20 Step apparatus for raising / lowering 21 Upper step 22 Lower step 22c Mounting part 24b Mounting part 31 Upper sheet member 32 Lower sheet member 32A Lower sheet member 33 Bolt 34 Bolt 34 'Bolt 35 Sheet member

Claims (3)

A truck for a construction machine comprising an upper step and a lower step arranged with a step on the upper and lower sides, wherein the upper step mounting portion and the lower step mounting portion are fixed to the track frame body by fastening bolts, respectively. In the frame,
A truck frame for a construction machine, wherein the lower surface of the mounting portion of the upper step and the upper surface of the mounting portion of the lower step are brought into contact with each other. A truck for a construction machine comprising an upper step and a lower step arranged with a step on the upper and lower sides, wherein the upper step mounting portion and the lower step mounting portion are fixed to the track frame body by fastening bolts, respectively. In the frame,
A seat member is provided between the upper step mounting portion and the lower step mounting portion, and the track frame body,
Positioning a part of the sheet member between the upper step mounting portion and the lower step mounting portion,
A track frame for a construction machine, wherein a lower surface of the mounting portion of the upper step and a part of the sheet member, and an upper surface of the mounting portion of the lower step and a part of the sheet member are brought into contact with each other. The upper step and the lower step have a footrest portion at the center in the width direction,
The track frame for a construction machine according to claim 1 or 2, wherein the footrest portion of the lower step is positioned outside the footrest portion of the upper step in the width direction of the construction machine.

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