JP2010036698A - Crawler frame, construction machinery equipped therewith, and manufacturing method for crawler frame - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure high connection strength between a housing mounting plate and a connection member without degrading work efficiency. <P>SOLUTION: A crawler frame is provided with a motor mounting plate 21 having a motor mounting surface 21b, an idler tumbler mounting plate 20 having an idler tumbler mounting surface 20b and a connection bar 25 extending in the longitudinal direction for connecting the motor mounting plate 21 with the idler tumbler mounting plate 20. At least one of the mounting plates 20, 21 is formed with a receiving hole 20a/21a capable of receiving an end portion of the connection bar 25 from rear surface 20c/21c side. The connection bar 25 is welded to the mounting plate 20/21 through a first fillet weld portion W2 provided between an end surface of the connection bar 25 inserted into the receiving holes 20a/21a and an inner side surface 20d/21d of the receiving hole 20a/21a and a second fillet weld portion W3 provided between a side surface of a mid-way portion of the connection bar 25 and the rear surface 20c/21c. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a crawler frame of a crawler traveling body provided in a construction machine such as a hydraulic excavator, a construction machine including the crawler frame, and a method of manufacturing the crawler frame.

  For example, as disclosed in Patent Document 1, a construction machine having a pair of track frames on a crawler frame of a traveling body is known.

  FIG. 15 is a side view schematically showing a configuration of a conventional crawler frame. FIG. 16 is an enlarged side view showing a part of FIG.

  As shown in the drawings, the crawler frame 101 includes a pair of left and right track frames 102 (only one of them is shown in the figure) and housing mounting plates 103 and 104 provided at both front and rear ends of the track frame 102, respectively. And a motor housing 105 and an idler housing 106 welded to the housing mounting plates 103 and 104, respectively. The motor housing 105 contains a motor (and drive wheels) not shown, and the idler housing 106 contains idle wheels not shown.

The track frame 102 includes a connecting member 107 provided between the housing mounting plates 103 and 104. Both front and rear end surfaces of the connecting member 107 are fixed to the housing mounting plates 103 and 104 by butt welding W1.
JP-A-8-58643

  The crawler frame 101 receives a reaction force in a vertical direction from the ground via unillustrated motors (drive wheels) and idle wheels located on both front and rear sides of the crawler frame 101. This reaction force causes a vertical bending stress as shown by an arrow Y1 in FIG. 16 in the butt weld W1 located between the motor and the idler wheel.

  In the conventional crawler frame 101, the connecting material 107 and the housing mounting plate 103, and the connecting material 107 and the housing mounting plate 104 are located at one place in the longitudinal direction of the connecting material 107 (butt welding W1). Therefore, the bending stress is concentrated on the butt weld W1, and it is difficult to sufficiently secure the bonding strength between the connecting member 107 and the housing mounting plates 103 and 104.

  In order to ensure the joining strength, as shown in FIG. 16, it is conceivable to form a groove at the tip of the connecting member 107 and perform the unequal leg welding, but the unequal leg welding has poor workability.

  The present invention has been made in view of the above problems, and a crawler frame capable of sufficiently securing the bonding strength between the housing mounting plate and the connecting material without impairing workability, and a construction machine including the crawler frame And it aims at providing the manufacturing method of a crawler frame.

  In order to solve the above problems, the present invention is a crawler frame that is provided in a lower traveling body of a construction machine and that holds a motor and idler wheels connected to drive wheels back and forth, and the motor is attached to the crawler frame. A motor mounting plate having a motor mounting surface, a idler wheel mounting plate having an idler wheel mounting surface for mounting the idler wheel, and a connecting member extending in the front-rear direction to connect the motor mounting plate and the idler wheel mounting plate And at least one of the motor mounting plate and idler wheel mounting plate receives the front and rear ends of the connecting member in the front-rear direction from the back side, which is the surface opposite to the motor mounting surface or idler wheel mounting surface. A joining surface surrounding a possible space, and the connecting material is a first fillet weld applied between an end surface of the connecting material inserted into a space inside the joining surface and the joining surface; Side and front of the middle part of the connecting material By a second fillet welding subjected between the back, the motor mounting plate, to provide a crawler frame, characterized in that it is welded to at least one of the idler wheel mounting plate.

  According to the present invention, the connecting material is welded to at least one of the motor mounting plate and the idler wheel mounting plate at two locations in the longitudinal direction of the connecting material (first and second fillet welds). Even when bending stress is generated between the connecting material and the mounting plate, unlike the conventional structure, the stress is distributed to two locations of the first and second fillet welds and concentrated in one location. Can be suppressed. Therefore, according to the present invention, it is possible to sufficiently ensure the bonding strength between the connecting material and the mounting plate.

  Further, in the present invention, since the strength can be improved by the fillet welding at two locations, it is possible to ensure the joining strength without impairing the workability as compared with the case of performing unequal leg welding as in the prior art. Is possible.

  In the crawler frame, the joint surface is provided on the motor mounting plate and the idler wheel mounting plate, and both front and rear end portions of the connecting material are attached to the both sides by the first fillet welding and the second fillet welding. It is preferably welded to the plate.

  According to this configuration, it is possible to sufficiently secure the joining strength of the connecting material in relation to both the motor mounting plate and the idler wheel mounting plate.

  In the crawler frame, the first fillet weld and the second fillet weld include a range including at least one of upper and lower corners among corners formed between the connecting material, the joint surface, and the back surface. It is preferable that it is applied.

  According to this configuration, since the first and second fillet welds function in a direction that opposes the bending stress in the vertical direction generated between the connecting material and each mounting plate, the joint strength can be improved more effectively. Can be achieved.

  In the crawler frame, it is preferable that the joining surface is an inner surface of a hole into which an end portion of the connecting material can be inserted.

  If comprised in this way, the movement to the up-down direction of a connection material will be controlled by the joint surface arrange | positioned at the upper and lower sides of a connection material. Therefore, according to this structure, since the rotation angle of the connecting material accompanying the vertical bending stress generated between the connecting material and the mounting plate can be kept small, the first and second fillet weldings can be performed. Together, it is possible to increase the strength to counter the bending stress.

  Further, the present invention comprises a pair of crawler frames, a lower traveling body having a motor and idler wheels respectively held before and after each of the crawler frames, and an upper body mounted on the lower traveling body, There is provided a construction machine, wherein each of the crawler frames is as described above.

  Furthermore, the present invention is a method for manufacturing a crawler frame for holding a motor and idler wheels connected to driving wheels back and forth, and a motor mounting plate having a motor mounting surface for mounting the motor In contrast, the step of inserting the rear end portion of the connecting material into the space inside the joint surface formed on the motor mounting plate from the back side, which is the surface opposite to the motor mounting surface, and the inside of the joint surface A step of performing fillet welding from the motor mounting surface side between the rear end surface of the connecting material inserted into the space and the joining surface, and a side surface of the intermediate portion of the connecting material and the back surface of the motor mounting plate A crawler comprising a step of performing fillet welding in between and a step of attaching a motor housing for covering the motor to the motor mounting surface after welding the connecting member and the motor mounting plate Frame manufacturing The law provides.

  According to the manufacturing method of the present invention, since the motor housing is attached to the motor mounting plate after the connecting member and the motor mounting plate are welded, the motor mounting surface is in a stage before mounting the motor housing. It becomes an open state, and fillet welding can be easily performed between the rear end surface of the connecting member that requires work from the motor mounting surface side and the joint surface. Therefore, by adopting the above method, it becomes possible to manufacture the motor housing as a work-in-process in a line different from the line for welding the connecting member and the motor mounting plate, and all operations are sequentially performed on the same line. Working time can be shortened compared to the case.

  According to the crawler frame manufactured by the above method, since the connecting material is welded to the motor mounting plate at two locations in the longitudinal direction of the connecting material, bending is performed between the connecting material and each mounting plate. Even when the stress is generated, unlike the conventional structure, it is possible to suppress the stress from being distributed to two welds and concentrated at one place. Therefore, according to the present invention, it is possible to sufficiently secure the bonding strength.

  As described above, in the crawler frame, since the strength can be improved by welding the fillet at two places, the joining strength can be ensured without performing the unequal leg welding as in the prior art. Therefore, it is possible to sufficiently secure the bonding strength between the connecting material and each mounting plate without impairing workability.

  The present invention is also a method for manufacturing a crawler frame for holding a motor and idler wheels connected to drive wheels back and forth, and an idler having an idler wheel mounting surface for attaching the idler wheels. A step of inserting a front end portion of a connecting material into a space inside a joint surface formed on the idler wheel mounting plate from a back side, which is a surface opposite to the idler wheel mounting surface, with respect to the wheel mounting plate; A step of performing fillet welding from the idler wheel mounting surface side between the front end face of the connecting member inserted in the space inside the surface and the joining surface, a side surface of the intermediate part of the connecting member, and the idler wheel A step of performing fillet welding between the back surface of the mounting plate, and a step of mounting an idler housing for covering the idler wheel to the idler wheel mounting surface after welding the connecting member and the idler wheel mounting plate A crawler frame characterized by comprising The law provides.

  According to the manufacturing method of the present invention, since the idler housing is attached to the idler wheel mounting plate after the connecting member and the idler wheel mounting plate are welded, the idler wheel is attached at a stage before the idler housing is attached. The mounting surface is opened, and fillet welding can be easily performed between the front end surface of the connecting member that requires work from the idler wheel mounting surface side and the joint surface. Therefore, by adopting the above method, it becomes possible to manufacture the motor housing as a work-in-process in a line different from the line for welding the connecting material and the idler wheel mounting plate, and all operations are sequentially performed on the same line. The working time can be shortened compared with the case where it is performed.

  And according to the crawler frame manufactured by the method, since the connecting material is welded to the idler wheel mounting plate at two locations in the longitudinal direction of the connecting material, between the connecting material and each mounting plate. Even when a bending stress is generated, unlike the conventional structure, it is possible to suppress the stress from being distributed to two welds and concentrated in one place. Therefore, according to the present invention, it is possible to sufficiently secure the bonding strength.

  As described above, in the crawler frame, since the strength can be improved by welding the fillet at two places, the joining strength can be ensured without performing the unequal leg welding as in the prior art. Therefore, it is possible to sufficiently secure the bonding strength between the connecting material and each mounting plate without impairing workability.

  According to the present invention, the bonding strength between the housing mounting plate and the connecting member can be sufficiently ensured without impairing workability.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a side view showing the overall configuration of a hydraulic excavator according to an embodiment of the present invention.

  Referring to FIG. 1, a hydraulic excavator 1 includes an upper swing body 2 and a lower traveling body 3 that supports the upper swing body 2.

  The upper revolving unit 2 includes a revolving frame 4 and a work attachment 5 provided on the revolving frame 4 so as to be raised and lowered. The work attachment 5 includes a boom 6 that is pivotally supported on the revolving frame 4, an arm 7 that is pivotally supported on the distal end portion of the boom 6, and a pivotable pivotally supported on the distal end portion of the arm 7. Bucket 8 is provided. The boom 6 is raised and lowered according to the expansion and contraction of the boom cylinder 9 provided between the revolving frame 4 and the boom 6. The arm 7 rotates with respect to the boom 6 according to the expansion and contraction of the arm cylinder 10 provided between the boom 6 and the arm 7. The bucket 8 swings according to the expansion and contraction of a bucket cylinder 11 provided between the arm 7 and the bucket 8.

  FIG. 2 is a side view showing a base frame of the hydraulic excavator of FIG. FIG. 3 is a plan view showing a base frame of the hydraulic excavator of FIG. In addition, it demonstrates below by making the advancing direction of the lower traveling body 3 into the front-back direction.

  With reference to FIGS. 1 to 3, the lower traveling body 3 includes a base frame 12 and a pair of crawlers 14 (one shown in FIG. 1) provided on the base frame 12. The base frame 12 supports the revolving frame 4 so as to be revolved, and has crawlers 14 on both the left and right sides. Since the crawler 14 has a target shape on the left and right, the crawler 14 on the right side will be mainly described below unless otherwise specified.

  FIG. 4 is a view taken in the direction of arrow IV in FIG. 3, in which the illustration of the right idler housing 22 is omitted. FIG. 5 is a view taken in the direction of the arrow V in FIG. 3 and omits the illustration of the right motor housing 23.

  The crawler 14 is attached to a crawler frame 15, a motor (not shown) attached to the rear portion of the crawler frame 15, a drive wheel 16 that rotates according to the driving of the motor, and a front portion of the crawler frame 15. An idler wheel 17, a drive wheel 16 and a crawler belt 18 wound around the idler wheel 17 are provided. By crawling the crawler belt 18 according to the rotational drive of the motor, the crawler 14 travels in the front-rear direction.

  The crawler frame 15 is joined to the base frame 12 and extends in the front-rear direction. The idler wheel mounting plate 20 and the motor mounting plate 21 provided at the front and rear ends of the track frame 19, and these mounting plates, respectively. 20 and 21 are provided with an idler housing 22 and a motor housing 23 (FIG. 4 shows the right idler housing 22 omitted, and FIG. 5 shows the right motor housing 23 omitted). .

  The track frame 19 includes a bowl-shaped member 24 formed in a U-shape that opens downward, and two right and left connecting bars (connecting members) 25 attached to the lower end of the bowl-shaped member 24. . The front end surface of the bowl-shaped member 24 is fixed to the rear surface (back surface) of the idler wheel mounting plate 20 by butt welding. Further, the rear end surface of the bowl-shaped member 24 is fixed to the front surface (back surface) of the motor mounting plate 21 by butt welding. The relationship between the connecting bar 25, the idler wheel mounting plate 20, and the motor mounting plate 21 will be described later.

  FIG. 6 is a perspective view showing the entire idler wheel mounting plate 20 of FIG. FIG. 7 is a perspective view showing the entire motor mounting plate 21 of FIG.

  6 and 7, the idler wheel mounting plate 20 is a metal plate having a thickness of 30 to 40 mm, and has a shape corresponding to the front shape of the hook-like member 24 so that the hook-like member 24 can be butt welded. It is said that. Similarly, the motor mounting plate 21 is a metal plate having a thickness of 30 to 40 mm, and has a shape corresponding to the front shape of the hook-like member 24 so that the hook-like member 24 can be butt welded.

  The mounting plates 20 and 21 are provided with receiving holes 20a and 21a penetrating in the front-rear direction at a pitch corresponding to the left and right intervals of the connecting bar 25. The connecting bars 25 are welded to the mounting plates 20 and 21 with their front and rear ends inserted into the receiving holes 20a and 21a.

  FIG. 8 is a side sectional view showing a welded state between the connecting bar 25 and the mounting plates 20 and 21. FIG. 9 is a view taken along arrow IX in FIG. 10 is a view taken in the direction of arrow X in FIG. Since the welding structure between the front end portion of the connecting bar 25 and the idler wheel mounting plate 20 and the welding structure between the rear end portion of the connecting bar 25 and the motor mounting plate 21 are the same, FIGS. Used as common to the plates 20 and 21.

  With reference to FIGS. 8 to 10, the end portion of the connecting bar 25 has a back surface 20 c that is a surface opposite to the mounting surfaces 20 b and 21 b to which the idler housing 22 or the motor housing 23 of each mounting plate 20 and 21 is mounted. It is inserted into the receiving holes 20a and 21a from the 21c side. The insertion depth of the connection bar 25 is substantially half the thickness of the mounting plates 20 and 21.

  A first fillet weld W2 is formed between the end surface of the connecting bar 25 and the inner side surfaces (joint surfaces) 20d and 21d of the receiving holes 20a and 21a. As shown in FIG. 9, the first fillet weld W <b> 2 is a range of four sides on the upper and lower sides and the left and right sides of the corners between the inner side surfaces 20 d and 21 d of the receiving holes 20 a and 21 a and the end surface of the connecting bar 25. Is formed over.

  On the other hand, as shown in FIG. 8, a second fillet weld W <b> 3 is formed between the side surface of the middle portion of the connecting bar 25 and the back surfaces 20 c and 21 c of the mounting plates 20 and 21. As shown in FIG. 10, the second fillet weld W3 extends over a range of four sides on the upper and lower sides and the left and right sides of the corner between the side surface of the connecting bar 25 and the rear surfaces 20c and 21c of the mounting plates 20 and 21. Is formed.

  Since the connection bar 25 and the mounting plates 20, 21 are thus fixed at two locations, the first fillet welded portion W2 and the second fillet welded portion W3, respectively, the arrows Y2, Y3 in FIG. As shown in FIG. 3, even when a bending stress in the vertical direction is generated, the bending stress can be dispersed at two locations of the welds W2 and W3 and can be prevented from being concentrated at one location. Therefore, it is possible to sufficiently secure the bonding strength between the connecting bar 25 and the mounting plates 20 and 21 against the bending stress.

  The idler housing 22 is butt welded from the front to the mounting surface 20b which is the front surface of the idler wheel mounting plate 20. The idler housing 22 is configured to hold the idler wheel 17 and cover a part of the idler wheel 17.

  The motor housing 23 is butt welded to the mounting surface 21b which is the rear surface of the motor mounting plate 21 from behind. The motor housing 23 holds a motor and drive wheels 16 (not shown) and covers a part of the motor.

  Hereinafter, a method for manufacturing the crawler frame 15 will be described with reference to FIGS.

  First, each connecting bar 25 is fixed to the hook-like member 24 by welding the lower end surface of the hook-like member 24 (see FIG. 11) to the upper surface of each connecting bar 25. Here, each connecting bar 25 is fixed to the hook-like member 24 with both front and rear end portions protruding from the hook-like member 24. In other words, the flange-shaped member 24 is welded to the mounting plates 20 and 21, whereas each connecting bar 25 is inserted into the receiving holes 20 a and 21 a of the mounting plates 20 and 21. Since it is welded to the mounting plates 20 and 21, it is necessary to project each connecting bar 25 from the hook-shaped member 24 by the amount of this insertion allowance.

  Next, as shown in FIG. 10, the front and rear ends of each connecting bar 25 are inserted into the receiving holes 20a and 21a of the mounting plates 20 and 21 from the back surfaces 20c and 21c, respectively, The mounting plates 20, 21 are welded by the first fillet weld W2 and the second fillet weld W3. Specifically, the first fillet weld W2 performs a welding operation from the side of the mounting surfaces 20b and 21b of the mounting plates 20 and 21. On the other hand, the second fillet weld W3 performs a welding operation from the rear surfaces 20c and 21c of the mounting plates 20 and 21.

  And before or after the welding operation of the first and second fillet welds W2 and W3, or after this operation, the front and rear end surfaces of the bowl-shaped member 24 and the back surfaces 20c and 21c of the mounting plates 20 and 21 are connected. Butt weld. Thereby, the track frame 19 and the mounting plates 20 and 21 are fixed.

  Next, as shown in FIG. 11, the crawler frame 15 can be manufactured by butt welding the idler housing 22 and the motor housing 23 to the mounting surfaces 20b and 21b of the mounting plates 20 and 21, respectively.

  As described above, according to the above-described embodiment, the connecting bar 25 is connected to each of the mounting plates 20 and 21 in two locations in the longitudinal direction of the connecting bar 25 (the first fillet weld W2 and the second fillet weld). Since it is welded in W3), even if a bending stress is generated between the connecting bar 25 and the mounting plates 20, 21, unlike the conventional structure, the first and second fillet welds W2, It is possible to suppress the concentration of stress in two locations of W3 and concentration in one location. Therefore, according to the present invention, it is possible to sufficiently secure the bonding strength between the connecting bar 25 and the mounting plates 20 and 21.

  Further, in the embodiment, since the strength can be improved by the fillet welding at two places, the joining strength is ensured without impairing the workability as compared with the case of performing unequal leg welding as in the prior art. It becomes possible.

  In the embodiment, the receiving holes 20a and 21a are formed in both of the mounting plates 20 and 21, and the first and second ends of the mounting plates 20 and 21 are connected to both the front and rear ends of the connecting bar 25, respectively. The configuration for applying the second fillet welds W2 and W3 has been described, but the first and second fillet welds are provided between at least one of the mounting plates 20 and 21 and one end of the connecting bar 25. If W2 and W3 are applied, a larger bonding strength can be obtained as compared with the conventional case.

  As in the above-described embodiment, the first and second fillet welds are configured to include upper and lower corners among the corners formed between the connecting bar 25, the inner side surfaces 20d and 21d, and the back surfaces 20c and 21c. In this case, the first and second fillet welds function in a direction that opposes the bending stress in the vertical direction. In the present embodiment, the configuration in which the first and second fillet welds include both the upper and lower corners has been described, but at least one of the upper and lower corners, that is, only the upper corner, or the lower corner Even when only the first and second fillet welds are provided, the strength against the bending stress can be improved.

  As in the above-described embodiment, the connecting bar 25 is inserted into the receiving holes 20a and 21a, so that the connecting bar 25 can be moved in the vertical direction by the inner side surfaces 20d and 21d arranged above and below the connecting bar 25. Be regulated. Therefore, according to the above embodiment, the rotation angle of the connecting bar 25 due to the vertical bending stress generated between the connecting bar 25 and the mounting plates 20 and 21 can be kept small. Combined with the two fillet welds W2 and W3, it is possible to increase the strength for resisting bending stress.

  Further, if the manufacturing method according to the above embodiment is employed, the motor housing 23 and the idler housing are mounted on the mounting surfaces 20b and 21b of the mounting plates 20 and 21 after welding the connecting bar 25 and the mounting plates 20 and 21, respectively. 22 is attached, so that the attachment surfaces 20b and 21b are opened before the motor housing 23 and the idler housing 22 are attached, and the connecting bar 25 requires work from the attachment surfaces 20b and 21b. And fillet welding between the joining surfaces 20d and 21d can be easily performed. Therefore, by adopting the above-described method, it becomes possible to manufacture the motor housing 23 and the idler housing 22 as work-in-progress products in a line different from the line for welding the connecting bar 25 and the mounting plates 20 and 21, respectively. Compared with the case where all operations are sequentially performed on the same line, the operation time can be shortened.

  And according to the crawler frame 15 manufactured by the above method, the connecting bar 25 is welded to each mounting plate 20, 21 at two locations in the longitudinal direction of the connecting bar 25. Even when a bending stress is generated between the mounting plates 20 and 21, unlike the conventional structure, the stress is distributed to the two welded portions W2 and W3 and is prevented from being concentrated at one location. Can do. Therefore, according to the crawler frame 15, the bonding strength can be sufficiently ensured.

  Thus, since the crawler frame 15 can improve the strength by the two fillet welds W2 and W3, it is possible to ensure the joining strength without performing the unequal leg welding as in the prior art. Therefore, according to the above method, it is possible to sufficiently secure the bonding strength between the connecting bar 25 and the mounting plates 20 and 21 without impairing workability.

  In the above-described embodiment, the example in which the end portions of the connecting bars 25 are inserted into the receiving holes 20a and 21a in the mounting plates 20 and 21 has been described. However, the holes need not necessarily be holes, as shown in FIG. Each connecting bar 25 can be inserted and fixed in the notches 20e and 21e.

  FIG. 12 is a side cross-sectional view showing another example of the welded state between the connecting bar 25 and the mounting plates 20 and 21. 13 is a view taken in the direction of arrow XIII in FIG. 14 is a view taken in the direction of arrow XIV in FIG. In the configuration shown in FIGS. 12 to 14, notches 20 e and 21 e are formed in the mounting plates 20 and 21 in place of the receiving holes 20 a and 21 a of the above embodiment.

  With reference to FIGS. 12-14, the edge part of the connection bar 25 is inserted in the notches 20e and 21e from the back surfaces 20c and 21c side of each mounting plate 20 and 21. As shown in FIG. The insertion depth of the connecting bar 25 is substantially half the thickness of the mounting plates 20 and 21 as in the above embodiment.

  A first fillet weld W4 is formed between the end surface of the connecting bar 25 and the inner surfaces (joint surfaces) 20f and 21f of the notches 20e and 21e. As shown in FIG. 13, the first fillet weld W4 is formed over the entire range (upper and left-right directions) of the corner between the notches 20e and 21e and the end face of the connecting bar 25.

  On the other hand, as shown in FIG. 12, a second fillet weld W5 is formed between the side surface of the middle portion of the connecting bar 25 and the rear surfaces 20c, 21c of the mounting plates 20, 21. As shown in FIG. 14, the second fillet weld W5 is formed over the entire range (upper and left-right directions) of the corner between the side surface of the connecting bar 25 and the rear surfaces 20c, 21c of the mounting plates 20, 21. Has been.

  Also in the said embodiment, since the connection bar 25 and each attachment plate 20 and 21 are being fixed by two places with the 1st fillet weld part W4 and the 2nd fillet weld part W5, the bending stress of an up-down direction is carried out. Concentration at one place can be suppressed, and the bonding strength between the mounting plates 20 and 21 and the connecting bar 25 can be sufficiently ensured.

  12 to 14 exemplify the notches 20e and 21e that open downward, but the same effect as that of the above-described embodiment can be obtained even when the notches are opened in the left-right direction.

1 is a side view showing an overall configuration of a hydraulic excavator according to an embodiment of the present invention. It is a side view which shows the base frame of the hydraulic shovel of FIG. It is a top view which shows the base frame of the hydraulic shovel of FIG. FIG. 4 is a view taken along arrow IV in FIG. 3, in which the illustration of the right idler housing is omitted. FIG. 4 is a view taken in the direction of the arrow V in FIG. 3, and illustration of the right motor housing is omitted. It is a perspective view which shows the whole idler wheel mounting plate of FIG. It is a perspective view which shows the whole motor mounting plate of FIG. It is side surface sectional drawing which shows the welding state of a connection bar and each attachment plate. It is IX arrow line view of FIG. FIG. 9 is a view on arrow X in FIG. 8. It is a figure for demonstrating the manufacturing method of the crawler frame of FIG. It is side surface sectional drawing which shows another example of the welding state of a connection bar and each attachment plate. It is a XIII arrow directional view of FIG. It is a XIV arrow directional view of FIG. It is a side view which shows the structure of the conventional crawler frame roughly. It is a side view which expands and shows a part of FIG.

Explanation of symbols

W2, W4 1st fillet welded part W3, W5 2nd fillet welded part 1 Hydraulic excavator (construction machine)
3 Lower traveling body 15 Crawler frame 16 Drive wheel 17 idler wheel 20 idler wheel mounting plate 20a, 21a receiving hole 20b idler wheel mounting surface 20c, 21c rear surface 20d, 21d, 20f, 21f inner side surface 21 motor mounting plate 21b motor mounting surface 22 Idler housing 23 Motor housing 25 Connection bar (connection material)

Claims (7)

A crawler frame that is provided in a lower traveling body of a construction machine and holds a motor and idler wheels connected to driving wheels back and forth,
A motor mounting plate having a motor mounting surface for mounting the motor;
An idler wheel mounting plate having an idler wheel mounting surface for mounting the idler wheel;
A connecting member that extends in the front-rear direction and connects the motor mounting plate and the idler wheel mounting plate;
At least one of the motor mounting plate and idler wheel mounting plate has a space in which the front and rear ends of the connecting member can be received in the front-rear direction from the back side, which is the surface opposite to the motor mounting surface or idler wheel mounting surface. Having an enclosing interface,
The connecting material includes a first fillet weld applied between an end surface of the connecting material inserted into a space inside the joining surface and the joining surface, a side surface of the intermediate portion of the connecting material, and the back surface. The crawler frame is welded to at least one of the motor mounting plate and the idler wheel mounting plate by second fillet welding performed between the motor and the idler wheel mounting plate.   The joint surface is provided on the motor mounting plate and the idler wheel mounting plate, and both front and rear ends of the connecting material are welded to the both mounting plates by the first fillet welding and the second fillet welding. The crawler frame according to claim 1.   The first fillet weld and the second fillet weld are performed in a range including at least one of the upper and lower corners among the corners formed between the connecting material and the joint surface and the back surface. The crawler frame according to claim 1 or 2.   The crawler frame according to any one of claims 1 to 3, wherein the joint surface includes an inner surface of a hole into which an end portion of the connecting material can be inserted.   A lower traveling body having a pair of crawler frames, a motor and idler wheels respectively held before and after each of the crawler frames, and an upper body mounted on the lower traveling body, wherein each of the crawler frames is claimed. Item 6. A construction machine described in any one of items 1 to 4. A method for manufacturing a crawler frame for holding a motor and idler wheels connected to drive wheels back and forth,
With respect to a motor mounting plate having a motor mounting surface for mounting the motor, a connecting material is inserted into the space inside the joint surface formed on the motor mounting plate from the back side, which is the surface opposite to the motor mounting surface. Inserting the end; and
A step of performing fillet welding from the motor mounting surface side between the rear end surface of the connecting member inserted in the space inside the joint surface and the joint surface;
A step of performing fillet welding between the side surface of the middle part of the connecting material and the back surface of the motor mounting plate;
And a step of attaching a motor housing for covering the motor to the motor mounting surface after welding the connecting member and the motor mounting plate. A method for manufacturing a crawler frame for holding a motor and idler wheels connected to drive wheels back and forth,
With respect to the idler wheel mounting plate having an idler wheel attachment surface for attaching the idler wheel, the space inside the joint surface formed on the idler wheel attachment plate from the back side that is the surface opposite to the idler wheel attachment surface Inserting the front end of the connecting material into
A step of performing fillet welding from the idler wheel mounting surface side between the front end surface of the connecting member inserted in the space inside the joint surface and the joint surface;
A step of performing fillet welding between a side surface in the middle of the connecting material and a back surface of the idler wheel mounting plate;
And a step of attaching an idler housing for covering the idler wheel to the idler wheel attachment surface after welding the connecting member and the idler wheel attachment plate.

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