JP3750849B2 - Counterweight screw receiver in construction machine and centering method of screw receiver - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of a screw receiver of a counterweight in a construction machine and a centering method of the screw receiver.
[0002]
[Prior art]
In general, a counterweight provided in a construction machine such as a hydraulic excavator is attached to a pedestal frame that is pivotably arranged on an upper portion of a traveling body. In this case, a mounting recess that opens downward is provided at the lower portion of the counterweight. A screw receiving body having a screw groove formed thereon is fixed to each of the mounting recesses, and a screw inserted from the frame frame side is screwed into each of the screw grooves, whereby a counterweight is mounted on the frame. It is fixed on the frame. By the way, the load of the counterweight acts on the fixed portion by each screw. However, since the counterweight is a weight member, if any of these screws has a screw shaft axis direction shift, There is a possibility that stress is concentrated on the displaced screw and the screw is damaged. In order to cope with this, it is necessary to center the screw shafts of the fixing portions so that the screw shafts are aligned in the vertical direction, and each screw receiving body has a groove direction of each screw groove. It must be mounted in the counterweight mounting recess with the aligned centering condition.
By the way, conventionally, as shown in FIG. 9, for example, as shown in FIG. 9, a pair of left and right concave groove portions 16a are formed at the lower portion of the counterweight 16 while the screw frame is attached to the counterweight. A convex portion that fits into each concave groove-shaped portion is formed, and screw receiving bodies 17 are respectively fitted and fixed to attachment concave portions 16b formed in a slab material that constitutes a groove bottom of each concave groove-shaped portion 16a. The tip of the screw inserted from the gantry frame convex portion is screwed into the screw groove 17a of the screw receiving member 17. In this case, each of the screw receiving bodies 17 includes a main body portion 17b in which a screw groove 17a is engraved and fitted into the mounting concave portion 16b, and a counterweight concave groove extending from the lower end edge of the main body portion 17b to the outer diameter side. The support portion 17c is formed along the groove measurement surface from the bottom surface of the groove portion 16a. When the support portion 17c is welded and fixed to the concave groove portion 16a, the posture of the support portion 17c is determined. By adjusting, the screw receiving body 17 is centered.
[0003]
[Problems to be solved by the invention]
However, in the conventional device, since the concave groove portion 16a and the convex portion are formed between the counterweight 16 and the mount frame, there is a problem that the structure becomes complicated and the screw receiver 17 Has a two-member configuration of the main body portion 17b and the support body portion 17c.
Therefore, as shown in FIG. 10, the screw receiving body 18 has only a main body portion in which the screw groove 18 a is engraved, and the lower portion of the counterweight 19 is flush with the lower portion in a plurality of left and right directions. It can be considered that the screw receiver 18 is fixed to the formed mounting recess (hole) 19a. By the way, in this case, in order to center the screw groove 18a of each screw receiving body 18, it can be performed by pressing a flat jig 20 against the lower end surface of each screw receiving body 18, but in this case, While there is a gap for inserting the screw receiver 18 between the screw receiver 18 and the mounting recess 19a, the screw receiver 18 is simply placed on the surface of the jig 20 under a load due to its own weight. Therefore, when welding between the upper end portion of the screw receiver 18 and the inner peripheral surface of the mounting recess 19a, the screw receiver 18 may be displaced and welding distortion may occur. As a result, there is a problem that the screw receiver 18 is misaligned. Furthermore, the screw receiver 18 has its lower end slightly protruded from the lower surface of the counterweight 19, and the protruding portion and the mounting recess 19a are also welded and fixed, so that the lower surface of the counterweight 19 is fixed to the jig 20. There is also a problem that the protrusion 20a for forming a space must be provided between the two, and the structure of the jig 20 becomes complicated, which has a problem to be solved by the present invention.
[0004]
[Means for Solving the Problems]
The present invention has been created in order to solve these problems in view of the above circumstances, and is provided with a mounting recess that opens downward in the counterweight, and a screw groove is formed in the mounting recess. In fixing the counterweight to the gantry frame by fixing the provided screw receptacle and screwing the screw into the screw groove from the gantry frame side, the screw receptacle is engraved with a screw groove, and the mounting A flat jig is pressed against the flange portion of the screw receiving body that is configured to include a main body portion that fits into the concave portion and a flange portion that is larger in diameter than the mounting concave portion. The screw receiver is configured to be centered.
In this way, in the centering state of the screw receiver, the flange portion is fixed between the hole edge of the mounting recess and the counterweight, and in this state, the screw receiver is placed in the mounting recess. By welding, it can be set as the screw receptacle body without a core shift.
Further, in the present invention, in order to fix the counterweight to the gantry frame, when fixing the screw receiver in which the screw groove is formed in the mounting recess provided in the counterweight, the screw receiver is engraved with the screw groove, A main body portion that fits into the mounting recess, and a flange portion that is larger in diameter than the mounting recess, and the screw receiving body is centered and fixed, and after the main body portion is inserted into the mounting recess, a flat plate is formed on the flange portion. It is characterized in that welding is performed in a state where the screw receiving body is centered by pressing a shaped jig.
By doing so, the screw receiving body can perform the welding operation while maintaining the centered state by the jig.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described based on the drawings of FIGS.
In the drawings, reference numeral 1 denotes a hydraulic excavator. The hydraulic excavator 1 has an upper swing body 3 supported on a crawler-type lower traveling body 2 so as to be rotatable. A front attachment 8 including member devices such as a boom 5, an arm 6, and a bucket 7 is attached to a substantially central portion of the frame 4. Further, a basic structure is the same as in the prior art, such as a cabin 9 provided on one side of the front attachment 8 and a tank chamber 10 such as a fuel tank or a hydraulic oil tank arranged on the other side. .
[0006]
Further, an engine chamber 11 in which an engine (not shown) and equipment devices around the engine are accommodated is disposed at the rear of the upper swing body 3, and a counterweight 12 is attached to the rear of the engine chamber 11 according to an attachment state described later. Has been. The counterweight 12 is set to be attached to the gantry frame 4 in a state in which the counterweight 12 is set to a load balanced with the work load by the front attachment 7.
[0007]
The counterweight 12 is formed in a curved shape so that the left and right ends are positioned forward, and a core portion 12a having a weight formed by laminating a plurality of slab materials in the vertical direction, and a steel plate The cover body 12b is formed by molding and covers the rear side surface of the core portion 12a and a part of the upper and lower end surfaces following the rear side surface. Of the slab materials constituting the core portion 12a, the lowermost slab material 12c located at the lowermost end has a central portion protruding in the protruding direction in the front-rear direction. In order for the four points to be fixed portions with the gantry frame 4, cylindrical through holes 12d penetrating in the vertical direction corresponding to the mounting recesses of the present invention are opened at the four points.
[0008]
A screw receiving body 13 for receiving a screw from the gantry frame 4 is fixed to each mounting recess 12d. The screw receiving body 13 is integrally formed with a main body portion 13a and a flange portion 13b. It has become a thing. The main body 13a is formed in a columnar shape whose outer diameter is smaller than the hole diameter of the mounting recess 12d so that the outer diameter fits into the mounting recess 12d, and a screw groove 13c that opens downward is formed in the shaft core portion. . On the other hand, the flange portion 13b is formed from the lower end portion of the main body portion 13a serving as the opening side end portion of the screw groove 13c toward the outer diameter side, and the outer diameter of the flange portion 13b is larger than the hole diameter of the mounting recess portion 12d. The flange portion 13b is set to come into contact with the hole edge of the mounting recess 12d when the main body portion 13a is fitted into the mounting recess 12d.
[0009]
Each screw receiving body 13 is centered so that the axial center of the screw groove 13c of the screw receiving body 13 is in the same direction in the state where it is attached to the mounting recess 12d. In this case, the main body 13a is attached. Each screw receiver 13 is set so that it can be centered by pressing (pressing) a flat jig 14 against the lower surface of the flange portion 13b of the screw receiver 13 fitted in the recess 12d. That is, as shown in FIG. 6, by pressing a flat jig 14 against the lower surface of the flange portion 13 b of each screw receiver 13, each screw receiver 13 is made upright with respect to the jig 14 surface. Centering is done by standing up. In this state, each screw receiver flange portion 13b is supported in a sandwiched manner between the lower surface of the counterweight 12 and the upper surface of the jig 14, and the load of the counterweight 12 is applied to the flange portion 13b. The main body 13a is fixed. As a result, the screw receiver 13 can be fixed in a state where the posture of the main body 13a that has been centered by the jig 14 is maintained. In this fixed state, the upper end of the main body 13a and the mounting recess By welding between the inner peripheral surface of 12d, even if a load is applied to the main body portion 13a, the main body portion 13a will not be displaced, so that each screw receiving body 13 is centered. It is set so that it can be welded (fixed) with the position of the
The screw receiver 13 is welded between the outer peripheral edge of the flange portion 13b and the lower surface of the counterweight 12 after the jig 14 is removed, whereby the screw receiver 13 is attached to the counterweight 12 of the screw receiver 13. The sticking of the is made more reliable.
[0010]
Then, the counterweight 12 having the screw receiving body 13 fixed to each mounting recess 12d is placed on the gantry frame 4, and the four screws (bolts) inserted upward from the corresponding part of the gantry frame 4 are mounted. ) 15 is set so that the counterweight 12 is fixed on the gantry frame 4 by screwing the tip ends of the screws 15 into the screw grooves 13c of the screw receivers 13, respectively. At this time, the screw groove 13c of each screw receiving body 13 is welded and fixed in the centering state in which the groove directions of the screw grooves 13c are the same as described above. Thus, the problem that stress is generated is eliminated, and the load of the counterweight 12 is set to act evenly on each screw 15.
[0011]
In the embodiment of the present invention configured as described above, a plurality of screw receiving bodies 13 are fixed to the counterweight 12 so as to fix the counterweight 12 to the gantry frame 4 with screws. In this case, each screw The receiving body 13 is formed with a flange portion 13b. When the screw receiving body main body portion 13a is fitted into the counterweight mounting recess 12d and the jig 14 is pressed against the flange portion 13b, the flange portion 13b is moved to the jig 14. And the counterweight 12 so as to receive the load of the counterweight 12. As a result, the posture of the screw receiving body main body portion 13a is fixed so as to be pressed in a state of being centered by the jig 14, and the upper end portion of the main body portion 13a is fixed to the inner peripheral surface of the mounting recess 12d. In the case of welding, there is no problem that the posture of the main body portion 13a is shifted and welding distortion occurs and the centering is impaired, and the load of the counterweight 12 is applied to the screw 15 of each screw receiving body 13. Thus, it is possible to prevent the screw 15 from being inadvertently damaged.
[0012]
As described above, in the embodiment of the present invention, the screw receiving body 13 fixed to the counterweight mounting recess 12d can be centered, and the flange portion 13b is formed at the lower end portion of the main body portion 13a. Since it can be configured as simple as that, and it can be configured with one member, it can be suppressed in terms of cost.
[0013]
Further, in this case, a flat plate material may be used as the jig 14, and the structure of the jig 14 can be simplified, and the mounting operation of the jig 14 can be simplified. , Further cost reduction can be measured.
[Brief description of the drawings]
FIG. 1 is a side view of a hydraulic excavator.
FIG. 2 is a partially omitted plan view of a hydraulic excavator.
FIGS. 3A, 3B, and 3C are a plan view, a front view, and a bottom view of a counterweight, respectively.
4A, 4B, and 4C are a side view and a side view of a counterweight, respectively, and an XX end view in FIG. 3B.
5A, 5B, and 5C are a plan view, a front view, and an end view taken along the line XX of FIG. 5B, respectively.
FIG. 6 is a cross-sectional view illustrating a centering state of a screw receiver.
FIG. 7 is a partially omitted plan view illustrating a state in which the counterweight is attached to the gantry frame.
8 is an end view taken along the line XX of FIG.
FIGS. 9A, 9B and 9C are a front view and a bottom view of a conventional counterweight, and a cross-sectional view illustrating a state in which a screw receiver is fixed to the counterweight.
FIG. 10 is a cross-sectional view for explaining a state of centering the counterweight of another conventional screw receiver.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hydraulic excavator 2 Lower traveling body 4 Base frame 12 Counterweight 12a Core part 12b Cover body 12d Through-hole 13 Screw receiving body 13a Body part 13b Flange part 13c Screw groove 14 Jig 15 Screw

Claims (2)

A mounting recess having a lower opening is opened in the counterweight, and a screw receiving body with a screw groove is fixed to the mounting recess, and a screw is screwed into the screw groove from the mounting frame side to mount the counterweight. When fixing to the frame, the screw receiving body is configured to include a main body portion that is provided with a screw groove and is fitted into the mounting concave portion, and a flange portion that is larger in diameter than the mounting concave portion. A screw receiver for a counterweight in a construction machine, wherein the screw receiver can be centered by pressing a flat jig against a flange portion of the screw receiver in an inserted state. In order to fix the counterweight to the gantry frame, when the screw receiving body formed with the screw groove is fixed to the mounting recess established in the counterweight, the screw receiving body is engraved with the screw groove and is fitted into the mounting recess. The main body part and a flange part having a diameter larger than that of the mounting concave part are configured, and the screw receiving body is centered and fixed. After the main body part is fitted into the mounting concave part, a flat jig is pushed into the flange part. A counterweight screw receiving body centering method in a construction machine, characterized in that welding is performed in a state where the screw receiving body is centered by contact.

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