JP2012020677A - Truck frame of crawler type vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformize strength of an inner plate and an outer plate of an idler wheel bracket, while keeping mud-sweeping performance of the idler wheel bracket.SOLUTION: An inner upper plate 18B of the inner plate 18 for constituting the idler wheel bracket 17 is inclined obliquely downward toward a rising plate 18A of the inner plate 18 from an idler wheel 6, and an outer upper plate 19B of the outer plate 19 is inclined obliquely downward toward a rising plate 19A of the outer plate 19 from the idler wheel 6. Thus, the inner plate 18 and the outer late 19 can be symmetrically formed in the lateral direction with the idler wheel 6 as the center. As a result of this, cross-sectional strength of the inner plate 18 fixed to a connecting flange 16 and cross-sectional strength of the outer plate 19 can be uniformized, and durability of the idler wheel bracket 17 can be enhanced.

Description

  The present invention relates to a track frame of a tracked vehicle including a crawler such as a hydraulic excavator or a hydraulic crane.

  In general, a hydraulic excavator as a representative example of a tracked vehicle is a self-propelled lower traveling body equipped with a crawler belt, an upper revolving body that is turnably mounted on the lower traveling body, and the upper revolving body. It is roughly constituted by a working device provided so as to be able to move up and down. The hydraulic excavator can stably travel on rough terrain such as a work site, and performs excavation work of earth and sand using a work device.

  In this case, the lower traveling body of the hydraulic excavator is usually provided on the left and right sides of the center frame with a track frame having side frames extending in the front and rear directions, and on the front and rear sides of the side frames. An idler wheel, a drive wheel provided on the other side of the front and rear sides of the side frame, and a crawler belt wound around the idler wheel and the drive wheel are provided.

  Here, the side frame is provided with a side frame main body located at the front and rear center portions and a connection flange on one side of the front and rear directions of the side frame main body, to which the idler wheel is attached. The bracket includes a driving wheel bracket that is provided on the other side of the front and rear directions of the side frame body via another connection flange and to which a driving wheel is attached.

  The side frame main body includes an inner surface plate that is attached to the leg portion of the center frame, an outer surface plate that faces the inner surface plate in the left and right directions, and an upper surface plate that connects between the inner surface plate and the upper end portion of the outer surface plate. It has an inverted U-shaped cross-sectional shape with an open bottom end and extends in the front and rear directions.

  On the other hand, the idler wheel bracket is usually arranged on the center frame side with the idler wheel interposed therebetween, and an inner plate provided with an inner upper plate bent toward the idler wheel on the upper end side, and the center frame with the idler wheel interposed therebetween. The outer plate is arranged on the opposite side and provided with an outer upper plate that is bent toward the idler wheel on the upper end side, and the idler wheel can be rotated between the inner plate and the outer plate. A yoke guide is provided for supporting the supporting yoke so as to be movable forward and backward.

  In addition, a tension adjusting device for adjusting the tension of the crawler belt is usually provided between the yoke supporting the idler wheel and the side frame main body, and when the crawler belt is deformed due to the undulation of the road surface, the tension adjusting device is The yoke moves forward and backward along the yoke guide of the idler wheel bracket according to the expansion and contraction of the coil spring. Accordingly, the distance between the idler wheel supported by the yoke and the drive wheel is appropriately changed according to the deformation of the crawler belt, and the crawler belt tension can be adjusted (for example, Patent Document 1). reference).

JP 2003-48570 A

  By the way, when the hydraulic excavator travels on rough terrain or muddy ground, mud etc. are jumped up by the crawler belt, so it is necessary to prevent the mud etc. from adhering to and accumulating on the side frame main body or idler wheel bracket.

  On the other hand, in the hydraulic excavator according to the prior art, the upper surface plate constituting the side frame main body is inclined obliquely downward from the inner surface plate toward the outer surface plate, so that the mud fallen on the upper surface plate along the inclination. What can discharge | emit to the outer surface board side is known.

  On the other hand, with respect to the idler wheel bracket, for example, by making the height dimension of the outer plate smaller than the height dimension of the inner plate, the inner upper plate of the inner plate and the outer upper plate of the outer plate are respectively separated from the inner plate. It is inclined diagonally downward toward the board. Thereby, the mud etc. which fell to the idler wheel bracket can be discharged | emitted to the outer side board side along the inclination of an inner upper board and an outer upper board.

  However, if the height of the outer plate constituting the idler wheel bracket is made smaller than the height of the inner plate in order to improve the mud scavenging property of the idler wheel bracket, means such as welding should be used on the connection flange. Compared to the strength (cross-sectional strength) of the inner plate to be joined using, the strength of the outer plate is lowered.

  As described above, when the strength of the inner plate supporting the idler wheel via the yoke and the strength of the outer plate are not uniform, for example, the hydraulic excavator performs turning travel (curve travel) in the left and right directions. As a result, the outer plate having low strength is twisted, and as a result, the durability of the idler bracket is lowered.

  The present invention has been made in view of the above-described problems of the prior art, and can improve the durability of the idler wheel bracket by making it possible to equalize the strength of the inner and outer plates while maintaining the mud sweeping property of the idler wheel bracket. It is an object of the present invention to provide a track frame for a tracked vehicle that can perform the above.

  In order to solve the above-described problems, the present invention comprises a center frame and a side frame attached to the center frame via left and right legs and extending in the front and rear directions. A side frame body located at the center in the rear direction, a front wheel frame bracket, a free wheel bracket provided on one side of the rear direction via a connection flange to which a free wheel is mounted, a front side of the side frame body, A driving wheel bracket provided on the other side in the rear direction via another connection flange, to which a driving wheel is attached, and the side frame main body includes an inner surface plate attached to the leg portion, the inner surface plate and the left, The floating plate comprises an outer surface plate facing rightward and an upper surface plate that connects the inner surface plate and the upper end portion of the outer surface plate and is inclined obliquely downward from the inner surface plate toward the outer surface plate. The bracket is disposed on the center frame side with the idler wheel interposed therebetween and has an inner plate provided with an inner upper plate on the upper end side, and is disposed on the opposite side of the center frame with the idler wheel disposed on the upper end side. The present invention is applied to a track frame of a tracked vehicle constituted by an outer plate provided with an upper plate.

  The invention of claim 1 is characterized in that the inner upper plate of the inner plate forms an inclined surface inclined obliquely downward from the idler wheel toward the inner plate, and the outer upper plate of the outer plate is The present invention has a configuration in which an inclined surface that is inclined obliquely downward from the idler wheel toward the outer plate is formed.

  According to the second aspect of the present invention, the side frame body includes a corner portion where the outer surface plate and the upper surface plate intersect with each other, and a corner portion where the outer plate and the outer upper plate of the idler wheel bracket intersect. A step portion having a dimension larger than the plate thickness dimension of the connection flange for connecting the frame body and the idler wheel bracket is formed.

  According to a third aspect of the present invention, there is provided a step formed between a corner portion where the outer surface plate and the upper surface plate of the side frame body intersect, and a corner portion where the outer plate and the outer upper plate of the idler wheel bracket intersect. The part is that the dimension is set to be not less than 2 times and not more than 5 times the plate thickness dimension of the connection flange.

  The invention according to claim 4 is that the inner plate and the outer plate of the idler wheel bracket are formed symmetrically in the left and right directions with the idler wheel interposed therebetween.

  According to a fifth aspect of the present invention, the inner upper plate and the outer upper plate of the idler wheel bracket are connected by an upper connecting plate extending in the left and right directions at a position adjacent to the connecting flange, and the upper connecting plate is There is a configuration in which it is inclined in a mountain shape so as to be symmetrical in the left and right directions from the central part in the left and right directions toward the inner and outer plates of the idler bracket.

  According to the invention of claim 1, the inner upper plate provided on the inner plate of the idler wheel bracket is inclined obliquely downward from the idler wheel toward the inner plate, and the outer upper plate provided on the outer plate is By inclining downward from the ring toward the outer plate, it is not necessary to reduce the height dimension of the outer plate relative to the inner plate, and the height dimension of the inner plate and the outer plate can be set substantially equal. . As a result, the strength of the inner plate (cross-sectional strength) and the strength of the outer plate (cross-sectional strength) that are joined to the connection flange by means of welding or the like can be made uniform, and when the tracked vehicle is turning, In such a case, it is possible to suppress the twisting of one of the inner plate and the outer plate constituting the idler wheel bracket and enhance the durability of the idler wheel bracket, thereby improving the reliability of the tracked vehicle. Can do.

  In addition, the inner upper plate provided on the inner plate and the outer upper plate provided on the outer plate are inclined to the left and right sides around the position of the idler wheel. Can be smoothly discharged along the inclined surfaces of the inner upper plate and the outer upper plate, and good mud scavenging property of the idler wheel bracket can be ensured.

  According to the second aspect of the present invention, the connecting flange is disposed between the corner portion where the outer surface plate and the upper surface plate of the side frame body intersect and the corner portion where the outer plate and the outer upper plate of the idler wheel bracket intersect. A step portion having a dimension larger than the plate thickness dimension is formed. For this reason, when the crawler belt wound around the idler wheel and the drive wheel is deformed by the undulation of the road surface, loads opposite to each other (shear load) are applied to the connection flange from the side frame body and the idler wheel bracket. Connected from the corner of the side frame body where the outer plate and the top plate meet, the point of load acting on the connection flange from the corner where the outer plate and top plate of the side frame body intersect, and from the corner where the outer plate and outer plate of the idler wheel bracket meet The distance from the point of application of the load acting on the flange can be increased. As a result, the shear stress acting on the connection flange can be reduced, and the durability of the connection flange can be increased.

  According to the third aspect of the present invention, the connecting flange is disposed between the corner portion where the outer surface plate and the upper surface plate of the side frame body intersect and the corner portion where the outer plate and the outer upper plate of the idler wheel bracket intersect. By forming the stepped portion that is not less than 2 times and not more than 5 times the plate thickness dimension, the shear stress acting on the connection flange can be further reduced, and the durability of the connection flange can be further enhanced.

  According to the invention of claim 4, the inner plate and the outer plate of the idler wheel bracket are formed symmetrically in the left and right directions with the idler wheel interposed therebetween, so that the connection flange is joined by means such as welding. The strength of the inner plate and the strength of the outer plate can be made uniform, and it is possible to reliably suppress the twisting of one of the inner plate and the outer plate constituting the idler wheel bracket.

  According to the invention of claim 5, the strength of the entire idler bracket can be increased by connecting the inner upper plate and the outer upper plate of the idler bracket by the upper connecting plate. Moreover, since the mud etc. which fell to the upper connection board are discharged | emitted to the inner side board side or the outer side board side along the mountain-shaped inclination of the said upper connection board, the mud sweeping property of an idler wheel bracket can be improved.

It is a front view which shows the hydraulic shovel provided with the track frame by embodiment of this invention. It is a perspective view which shows a track frame alone. It is a perspective view which shows a side frame alone. FIG. 4 is an enlarged cross-sectional view of the idler wheel bracket, idler wheel, connection flange, and side frame body as viewed from the direction of arrows IV-IV in FIG. 1 with the crawler belt omitted. FIG. 5 is an enlarged cross-sectional view similar to FIG. 4, showing the idler wheel bracket, the connection flange, and the side frame body with the idler wheel removed. It is sectional drawing seen from the arrow VI-VI direction in FIG. 5 which shows an idle wheel bracket, a connection flange, and a side frame main body. It is sectional drawing which shows the idler wheel bracket by a comparative example, a connection flange, and a side frame main body. It is sectional drawing seen from the arrow VIII-VIII direction in FIG. 7 which shows the idler wheel bracket by a comparative example, a connection flange, and a side frame main body. It is an expanded sectional view similar to FIG. 5 which shows the idler wheel bracket by a modification.

  Hereinafter, a case where a track frame of a tracked vehicle according to an embodiment of the present invention is applied to a hydraulic excavator will be described as an example and described in detail with reference to the accompanying drawings.

  In the figure, reference numeral 1 denotes a hydraulic excavator as a typical example of a tracked vehicle. The hydraulic excavator 1 includes a tracked lower traveling body 2 capable of self-propelling and a swivel wheel 3 on the lower traveling body 2. An excavation work of earth and sand using the working device 5, which is roughly constituted by an upper swiveling body 4 that is mounted so as to be able to swivel, and a work device 5 that is provided on the front side of the upper swiveling body 4 so as to be able to move up and down. Etc.

  Here, the track-type (crawler-type) lower traveling body 2 is for traveling on uneven surfaces such as construction sites and rough terrain, and includes one end of a track frame 11 described later and a side frame 14 described later. An idler wheel 6 provided rotatably on the side, a drive wheel 7 provided on the other end of the side frame 14, and a crawler belt 8 provided around the idler wheel 6 and the drive wheel 7. And is roughly composed.

  Next, reference numeral 11 denotes a track frame according to the present embodiment, and the track frame 11 is a base of the lower traveling body 2. Here, as shown in FIG. 2, the track frame 11 is roughly constituted by a center frame 12 located in the center and side frames 14 described later disposed on both the left and right sides of the center frame 12. ing.

  Reference numeral 12 denotes a center frame that constitutes the center portion of the track frame 11. The center frame 12 is formed in a substantially X shape when viewed from above, and is formed in an X shape that is substantially equal to the upper plate 12A. The lower plate 12B disposed at a lower side of the upper plate 12A and a large number of (for example, eight) connecting plates 12C that connect the upper plate 12A and the lower plate 12B are configured to be strong. A support structure is formed.

  Here, on the left and right sides of the center frame 12, there are four leg portions 12D composed of the upper plate 12A, the lower plate 12B, and the connecting plates 12C, two apart from each other at the front and rear. Provided, left and right side frames 14 to be described later are attached to the distal ends of the respective leg portions 12D. Further, a large-diameter cylindrical round cylinder 13 is provided at the center of the upper plate 12 </ b> A, and the upper swing body 4 is mounted on the round cylinder 13 via the rotary wheel 3.

  Next, reference numeral 14 denotes left and right side frames according to the present embodiment. These left and right side frames 14 are arranged on both the left and right sides of the center frame 12 and extend in the front and rear directions. Yes. Here, as shown in FIG. 3 and the like, the side frame 14 is roughly composed of a side frame body 15, an idler wheel bracket 17, and a drive wheel bracket 26 described later.

  Reference numeral 15 denotes a side frame main body located in the center of the front and rear direction (length direction) of the side frame 14, and the side frame main body 15 is provided with a means such as welding at the tip of the left leg portion 12D of the center frame 12. The inner surface plate 15A that is fixed and rises substantially vertically, the outer surface plate 15B that faces the inner surface plate 15A in the left and right directions and rises substantially vertically, and the upper end portion of the inner surface plate 15A and the upper end portion of the outer surface plate 15B. Are formed with an inverted U-shaped cross-sectional shape having an opening on the lower end side, and extend in the front and rear directions.

  A free wheel bracket 17 is attached to one end side in the front and rear directions of the side frame main body 15 via a connection flange 16 described later, and the other end side in the front and rear directions of the side frame main body 15 is described later. A drive wheel bracket 26 is attached via another connecting flange 25.

  Here, in the side frame main body 15, the height dimension H2 of the outer surface plate 15B is set smaller than the height dimension H1 of the inner surface plate 15A (H1> H2). Accordingly, the corner portion (corner portion) 15D where the inner surface plate 15A and the upper surface plate 15C intersect is positioned higher than the corner corner portion 15E where the outer surface plate 15B and the upper surface plate 15C intersect, and the inner surface plate 15A and the outer surface plate 15B. The upper surface plate 15C that connects the upper end portions of the upper and lower surfaces forms an inclined surface that is inclined obliquely downward from the inner surface plate 15A toward the outer surface plate 15B. In this case, as shown in FIGS. 2 and 4, there is almost no step between the upper surface plate 15 </ b> C constituting the side frame body 15 and the upper surface of the upper plate 12 </ b> A constituting the leg portion 12 </ b> D provided on the center frame 12. A continuous inclined surface is formed. Thereby, even when the mud or the like jumped up by the crawler belt 8 during the traveling of the excavator 1 falls on the side frame body 15, the mud or the like is discharged to the outer surface plate 15B side along the inclination of the upper surface plate 15C. It has a configuration that can.

  Reference numeral 16 denotes a connection flange provided on one end side in the front and rear directions of the side frame main body 15. The connection flange 16 has a substantially J-shape on the idler wheel bracket 17 side, which will be described later, on the lower end side of a thick steel plate material. It is formed by bending. Here, as shown in FIG. 4 and the like, the connection flange 16 has a substantially similar shape to the outer shape when the idler wheel bracket 17 is viewed from the front, and is slightly larger than the outer shape of the idler wheel bracket 17. It is formed as a body, and its thickness T is set to about 19 mm to 25 mm, for example. Then, the rear surface 16A of the connection flange 16 is fixed to an end edge portion on one end side of the side frame body 15 by means of welding or the like, and an idler wheel bracket 17 described later is welded to the front surface 16B of the connection flange 16 or the like. It is fixed using the means.

  In this case, the inner end edge 16C located on the leg 12D side of the center frame 12 in the connection flange 16 is closer to the leg 12D side (center frame 12 side) than the joint with the inner surface plate 15A of the side frame body 15. It protrudes. Further, a yoke insertion hole 16D through which a yoke (not shown) for supporting the idler wheel 6 so as to be movable in the front and rear directions is inserted in the center portion of the connection flange 16 is formed. Therefore, the connection flange 16 maintains the welding strength of each end edge of the side frame 14 as a whole even when the end edge shape of the side frame body 15 and the end edge shape of the idler wheel bracket 17 are different. It functions as a strength member.

  Reference numeral 17 denotes an idler wheel bracket provided on one side of the front and rear directions of the side frame main body 15 via the connection flange 16. The idler wheel bracket 17 is fixed to the front surface 16B of the connection flange 16 by means of welding or the like, and the idler wheel 6 is attached to be rotatable and movable in the front and rear directions. Here, as shown in FIGS. 4 to 6, the idler wheel bracket 17 is roughly constituted by an inner plate 18, an outer plate 19, an upper connecting plate 21, an inner guide 22, and an outer guide 23 which will be described later. ing.

  Reference numeral 18 denotes an inner plate disposed on the center frame 12 side with the idler wheel 6 interposed therebetween. The inner plate 18 rises substantially vertically while facing the idler wheel 6, and the riser plate 18A The inner upper plate 18B is bent toward the idler wheel 6 from the upper end side. The inner plate 18 is fixed to the front face 16B of the connection flange 16 by means of welding or the like at the rear end edge, and extends from the connection flange 16 in the front and rear directions. Further, an inner guide 22 described later is provided on a surface of the inner plate 18 that faces the idler wheel 6.

  Here, the inner upper plate 18B of the inner plate 18 forms an inclined surface inclined obliquely downward from the idler wheel 6 toward the inner plate 18 (rising plate 18A). Thereby, the mud etc. which fell on the inner upper board 18B of the inner board 18 become a structure discharged | emitted to the inner board 18 side along the inclination of this inner upper board 18B.

  Reference numeral 19 denotes an outer plate disposed on the opposite side to the center frame 12 with the idler wheel 6 interposed therebetween. The outer plate 19 includes a rising plate 19A that rises substantially vertically while facing the idler wheel 6 and the rising plate 19A. The upper and lower plates 19B are bent toward the idler wheel 6 from the upper end side of the plate 19A. The outer plate 19 is fixed to the front surface 16B of the connection flange 16 by a means such as welding at the rear end edge, and extends from the connection flange 16 in the front and rear directions. In addition, an outer guide 23 described later is provided on a surface of the outer plate 19 that faces the idler wheel 6.

  Here, the outer upper plate 19B of the outer plate 19 forms an inclined surface inclined obliquely downward from the idler wheel 6 toward the outer plate 19 (rising plate 19A). Thereby, the mud etc. which fell on the outer upper board 19B of the outer side board 19 become a structure discharged | emitted to the outer side board 19 side along the inclination of this outer upper board 19B.

  In this way, the inner upper plate 18B of the inner plate 18 and the outer upper plate 19B of the outer plate 19 constituting the idler wheel bracket 17 are inclined diagonally downward on both left and right sides with respect to the position of the idler wheel 6. An inclined angled surface is formed. Thereby, the height dimension of the inner side board 18 and the height dimension of the outer side board 19 can be set substantially equal, and the inner side board 18 and the outer side board 19 are symmetrical with respect to the left and right directions around the idler wheel 6. Is formed.

  For this reason, as shown in FIG. 5, the corner 19C where the outer plate 19 (rising plate 19A) constituting the idler wheel bracket 17 and the outer upper plate 19B intersect is the outer plate 15B of the side frame body 15 and the upper plate. 15C is arranged at a position higher than the corner 15E where the corner 15C intersects, and between the corner 19C of the outer plate 19 constituting the idler wheel bracket 17 and the corner 15E of the side frame body 15, the upper and lower A step 20 in the direction can be formed.

  In this case, the dimension L of the step portion 20 is set to be larger than the plate thickness dimension T of the connection flange 16 to which the side frame body 15 and the idler wheel bracket 17 are fixed, and preferably the plate thickness dimension T of the connection flange 16. The dimension is set to be not less than 2 times and not more than 5 times. For example, when the plate thickness dimension T of the connection flange 16 is 20 mm, the dimension L of the stepped portion 20 is set to 40 mm or more and 100 mm or less.

  Thus, in the present embodiment, the thickness F of the connecting flange 16 is determined between the corner 19C of the outer plate 19 constituting the idler wheel bracket 17 and the corner 15E of the side frame body 15. The step portion 20 having a large dimension L is also formed. Thereby, due to the tension of the crawler belt 8 wound around the idler wheel 6 and the drive wheel 7, the load in the direction indicated by the arrow F1 from the corner corner portion 15E of the side frame body 15 toward the connection flange 16 as shown in FIG. When (shear load) is applied and a load (shear load) in the direction of arrow F2 is applied from the corner 19C of the outer plate 19 constituting the idler wheel bracket 17 toward the connection flange 16, the corner 15E The distance (the dimension L of the stepped portion 20) between the point P1 of the load acting on the connecting flange 16 and the point P2 of the load acting on the connecting flange 16 from the corner 19C is kept at a relatively large value. The shear stress acting on the connection flange 16 can be reduced accordingly.

  Reference numeral 21 denotes an upper connecting plate that connects the inner upper plate 18B of the inner plate 18 and the outer upper plate 19B of the outer plate 19, and the upper connecting plate 21 is substantially flat in plan view using a thick steel plate material or the like. It is formed in a U-shape and extends in the left and right directions at a position adjacent to the connection flange 16. The upper connecting plate 21 is fixed to the front surface 16B of the connection flange 16, the inner upper plate 18B of the inner plate 18 and the outer upper plate 19B of the outer plate 19 by means of welding or the like, and the inner plate 18 to the connection flange 16 is secured. And the bonding strength of the outer plate 19 are reinforced.

  Here, the upper connecting plate 21 forms a mountain-shaped inclined surface so as to be symmetrical in the left and right directions from the central portion in the left and right directions toward the inner plate 18 and the outer plate 19 of the idler wheel bracket 17. ing. As a result, the mud or the like dropped on the upper connecting plate 21 is discharged along the inclined surface of the upper connecting plate 21 to the inner plate 18 side or the outer plate 19 side of the idler wheel bracket 17. .

  Reference numeral 22 denotes an inner guide provided on a surface of the inner plate 18 that faces the idler wheel 6. The inner guide 22 has a substantially L-shaped cross-sectional shape and extends in the front and rear directions. It consists of 22B. The upper guide frame 22A is fixed to the rising plate 18A and the inner upper plate 18B of the inner plate 18 by means of welding or the like, and the rising plate 18A, the inner upper plate 18B, and the guide frame 22A A closed space 22C is formed between them. On the other hand, the lower guide frame 22B is fixed to the rising plate 18A of the inner plate 18 by means of welding or the like, and a closed space 22D is formed between the rising plate 18A and the guide frame 22B. . In addition, a gap extending in the front and rear directions is formed between the upper and lower guide frames 22A and 22B at a constant interval.

  Reference numeral 23 denotes an outer guide provided on a surface of the outer plate 19 facing the idler wheel 6, and the outer guide 23 has a substantially L-shaped cross-sectional shape and extends in the front and rear directions, like the inner guide 22. , Lower guide frames 23A and 23B. The upper guide frame 23A is fixed to the rising plate 19A and the outer upper plate 19B of the outer plate 19 by means of welding or the like, and the rising plate 19A, the outer upper plate 19B, and the guide frame 23A A closed space 23C is formed between them. On the other hand, the lower guide frame 23B is fixed to the rising plate 19A of the outer plate 19 by means of welding or the like, and a closed space 23D is formed between the rising plate 19A and the guide frame 23B. . Further, a gap extending in the front and rear directions is formed between the upper and lower guide frames 23A and 23B with a certain interval.

  A yoke (not shown) is formed in a gap formed between the upper and lower guide frames 22A and 22B on the inner guide 22 and a gap formed between the upper and lower guide frames 23A and 23B on the outer guide 23. A pair of left and right bearings 24 attached to the front end side of the support shaft 6A is movably disposed in the front and rear directions, and both end sides of the support shaft 6A provided on the idler wheel 6 are connected to the left and right bearings 24. It is rotatably supported. As a result, the idler wheel 6 can move forward and backward while being guided by the inner guide 22 and the outer guide 23 of the idler wheel bracket 17 while being supported rotatably by the left and right bearings 24. ing.

  Here, the inner plate 18 and the outer plate 19 constituting the idler wheel bracket 17 are symmetrically formed in the left and right directions with the idler wheel 6 as the center, so that the guide frame 22A of the inner plate 18 and the inner guide 22 is formed. The closed space 22C formed between the outer plate 19 and the guide frame 23A of the outer guide 23 can be formed as a closed space having substantially the same cross-sectional area. . Further, a closed space 22D formed between the inner plate 18 and the guide frame 22B of the inner guide 22 and a closed space 23D formed between the outer plate 19 and the guide frame 23B of the outer guide 23 are substantially It can be formed as a closed space having an equal cross-sectional area.

  Thereby, the cross-sectional strength of the inner plate 18 fixed to the connection flange 16 and the cross-sectional strength of the outer plate 19 can be made uniform. One of them is configured to be able to suppress the occurrence of twisting.

  Reference numeral 25 denotes another connection flange fixed to the other end side in the front and rear direction of the side frame main body 15, and 26 denotes the other side of the front and rear direction of the side frame main body 15 through the other connection flange 25. The drive wheel bracket provided is shown. Here, the other connection flange 25 also maintains the welding strength between the side frame main body 15 and the drive wheel bracket 26.

  The drive wheel 7 is attached to the drive wheel bracket 26, and the crawler belt wound around the idler wheel 6 and the drive wheel 7 by rotationally driving the drive wheel 7 by a traveling hydraulic motor (not shown). 8 is configured to circulate. In this case, a tension adjusting device (not shown) is provided between the idler wheel 6 and the side frame main body 15, and even when the crawler belt 8 is deformed by undulation of the road surface when the hydraulic excavator 1 travels, the tension adjusting device. Thus, the tension of the crawler belt 8 can be adjusted appropriately by changing the distance between the idle wheel 6 and the drive wheel 7.

  The hydraulic excavator 1 according to the present embodiment has the track frame 11 as described above, and the self-propelled to the work site by rotating the driving wheel 7 and rotating the crawler belt 8 between the idler wheel 6 and the excavator 1. Then, excavation work of earth and sand is performed using the working device 4.

  Here, when the hydraulic excavator 1 travels, mud or the like is jumped up by the crawler belt 8, and the mud or the like falls onto the side frame main body 15, the idler wheel bracket 17, and the like that constitute the side frame 14.

  On the other hand, the side frame main body 15 according to the present embodiment includes an upper end portion of the inner surface plate 15A disposed on the center frame 12 side and an upper end portion of the outer surface plate 15B disposed on the side opposite to the center frame 12. The upper surface plate 15C that connects the two surfaces forms an inclined surface that is inclined obliquely downward from the inner surface plate 15A toward the outer surface plate 15B. Thereby, even when mud falls on the side frame main body 15, this mud etc. can be discharged | emitted to the outer surface board 15B side along the inclination of the upper surface board 15C.

  On the other hand, in the idler wheel bracket 17 according to the present embodiment, the inner upper plate 18B of the inner plate 18 located on the center frame 12 side with the idler wheel 6 interposed therebetween is inclined obliquely downward from the idler wheel 6 toward the inner plate 18. The outer upper plate 19B of the outer plate 19 located on the opposite side of the center frame 12 with the idler wheel 6 interposed therebetween is inclined obliquely downward from the idler wheel 6 toward the outer plate 19 It is formed as a surface.

  As a result, even when mud or the like falls on the idler wheel bracket 17, the mud or the like is discharged to the inner plate 18 side along the inclination of the inner upper plate 18B, and the outer plate along the inclination of the outer upper plate 19B. It can be discharged to the 19th side. Thus, mud etc. are prevented from accumulating on the inner upper plate 18B of the inner plate 18 and the outer upper plate 19B of the outer plate 19 constituting the idler wheel bracket 17, and the mud sweeping property of the idler wheel bracket 17 is improved. By keeping it, the crawler belt 8 can smoothly move between the idler wheel 6 and the drive wheel 7.

  Moreover, in the idler wheel bracket 17 according to the present embodiment, the inner upper plate 18B of the inner side plate 18 and the outer upper plate 19B of the outer side plate 19 are diagonally inclined on the left and right sides with respect to the position of the idler wheel 6. By forming the angled inclined surface inclined downward, the height dimension of the inner plate 18 and the height dimension of the outer plate 19 can be set substantially equal, and the inner plate 18 and the outer plate 19 can be moved freely. The ring 6 can be symmetrically formed in the left and right directions.

  Thereby, a closed space 22C formed between the inner plate 18 and the guide frame 22A of the inner guide 22, and a closed space 23C formed between the outer plate 19 and the guide frame 23A of the outer guide 23, It can be formed as a closed space having approximately the same cross-sectional area. Further, a closed space 22D formed between the inner plate 18 and the guide frame 22B of the inner guide 22 and a closed space 23D formed between the outer plate 19 and the guide frame 23B of the outer guide 23 are substantially It can be formed as a closed space having an equal cross-sectional area.

  Thereby, the cross-sectional strength of the inner plate 18 fixed to the connection flange 16 and the cross-sectional strength of the outer plate 19 can be made uniform, and when the excavator 1 performs left turn traveling and right turn traveling, It is possible to suppress the twisting of one of the plate 18 and the outer plate 19. As a result, the durability of the idle wheel bracket 17 can be increased, and the stability of the excavator 1 during travel can be increased.

  Further, by forming the inner plate 18 and the outer plate 19 of the idler wheel bracket 17 symmetrically in the left and right directions around the idler wheel 6, as shown in FIG. 5, the outer plate 19 (rising plate 19A) is formed. A step 20 having a dimension L larger than the plate thickness dimension T of the connection flange 16 is formed between the corner 19C where the outer plate 19B intersects with the corner 15E of the side frame body 15. Can do.

  Therefore, due to the tension of the crawler belt 8 wound around the idler wheel 6 and the drive wheel 7, the load in the direction indicated by the arrow F1 from the corner corner portion 15E of the side frame body 15 toward the connection flange 16 as shown in FIG. When the load in the direction of arrow F2 acts from the corner corner 19C of the outer plate 19 constituting the idler wheel bracket 17 toward the connection flange 16, the load acting on the connection flange 16 from the corner corner 15E. The distance (the dimension L of the stepped portion 20) between the acting point P1 and the acting point P2 of the load acting on the connecting flange 16 from the corner 19C can be kept at a relatively large value.

  As a result, an arrow F1 direction load acting on the connection flange 16 from the corner corner 15E of the side frame body 15 and an arrow acting on the connection flange 16 from the corner corner 19C of the outer plate 19 constituting the idler wheel bracket 17 are shown. The shear stress acting on the connection flange 16 due to the load in the direction F2 can be reduced, and the durability of the connection flange 16 can be increased.

  Next, a comparison between the side frame 14 according to the present embodiment shown in FIGS. 5 and 6 and the side frame 114 according to the comparative example shown in FIGS. 7 and 8 will be described.

  First, the side frame 114 according to the comparative example is attached to the side frame main body 15 similar to the side frame 14 according to the present embodiment and the front and rear sides of the side frame main body 15 via the connection flange 116. An idler wheel bracket 117 described later is provided.

  Here, as shown in FIG. 7, the side frame body 15 constituting the side frame 114 according to the comparative example is similar to the one according to the present embodiment in that the outer surface plate 15B is compared with the height dimension H1 of the inner surface plate 15A. The upper surface plate 15C connecting the upper end portions of the inner surface plate 15A and the outer surface plate 15B forms an inclined surface inclined obliquely downward from the inner surface plate 15A toward the outer surface plate 15B. Yes.

  On the other hand, the idler wheel bracket 117 according to the comparative example includes an inner plate 118 composed of a rising plate 118A and an inner upper plate 118B, an outer plate 119 composed of a rising plate 119A and an outer upper plate 119B, and an inner upper plate of the inner plate 118. An upper connecting plate 120 for connecting between 118B and the outer upper plate 119B of the outer plate 119, an inner guide 121 having upper and lower guide frames 121A and 121B provided on the inner surface side of the inner plate 118, and an outer plate An outer guide 122 having upper and lower guide frames 122A and 122B provided on the inner surface side of 119 is formed.

  In this case, the inner upper plate 118B of the inner plate 118 extends in the horizontal direction from the upper end side of the rising plate 118A toward the idler wheel. On the other hand, the outer upper plate 119B of the outer plate 119 forms an inclined surface inclined obliquely downward from the idler wheel toward the rising plate 119A. The inclination of the outer upper plate 119B is the same as that of the upper surface plate 15C of the side frame body 15. The inclination angle is set to be approximately equal.

  Thus, in the idler wheel bracket 117 of the side frame 114 according to the comparative example, only the outer upper plate 119B of the outer plate 119 is inclined obliquely downward from the position of the idler wheel toward the rising plate 119A, and the inner plate 118 The height dimension of the outer side plate 119 is set smaller than the height dimension.

  For this reason, in the side frame 114 according to the comparative example, the outer plate 119 and the outer guide 122 are compared with each other in the closed space 121C formed between the inner plate 118 of the idler wheel bracket 117 and the guide frame 121A of the inner guide 121. The cross-sectional area of the closed space 122C formed between the guide frame 122A is reduced. As a result, the cross-sectional strength of the outer plate 119 is insufficient compared to the cross-sectional strength of the inner plate 118 fixed to the connection flange 116, and the outer plate 119 side is likely to be twisted when the excavator 1 turns. There arises a problem that the stability during running is lowered.

  On the other hand, in the side frame 114 of the comparative example, the corner portion 119C where the rising plate 119A of the outer plate 119 and the outer upper plate 119B that constitute the idler wheel bracket 117 intersect with the corner portion 15E of the side frame main body 15. The dimension L ′ of the upper and lower stepped portion 123 formed therebetween is smaller than the plate thickness dimension T ′ of the connection flange 116 to which the side frame body 15 and the idler wheel bracket 117 are fixed (L '<T').

  For this reason, in the side frame 114 according to the comparative example, as shown in FIG. 8, a load in the direction of arrow F1 acts from the corner portion 15E of the side frame body 15 toward the connection flange 116 due to the tension of the crawler belt. When a load in the direction of arrow F2 is applied from the corner 119C of the outer plate 119 constituting the bracket 117 toward the connection flange 116, an application point P1 of the load acting on the connection flange 116 from the corner 15E, The distance (the dimension L ′ of the stepped portion 123) between the corner portion 19C and the load application point P2 acting on the connection flange 116 is reduced. As a result, the load in the arrow F1 direction acting on the connection flange 116 from the corner corner 15E of the side frame body 15 and the arrow acting on the connection flange 116 from the corner corner 119C of the outer plate 119 constituting the idler wheel bracket 117. The shear stress acting on the connection flange 116 due to the load in the direction indicated by F2 increases, and there arises a problem that the durability of the connection flange 116 decreases.

  On the other hand, in the side frame 14 according to the present embodiment, the inner upper plate 18B of the inner plate 18 constituting the idler wheel bracket 17 is inclined obliquely downward from the idler wheel 6 toward the rising plate 18A of the inner plate 18. An inclined surface is formed, and the outer upper plate 19B of the outer plate 19 forms an inclined surface that is inclined obliquely downward from the idler wheel 6 toward the rising plate 19A of the outer plate 19. Thereby, the height dimension of the inner side board 18 and the height dimension of the outer side board 19 can be set substantially equal, and the inner side board 18 and the outer side board 19 are symmetrical about the idler wheel 6 in the left and right directions. Can be formed.

  For this reason, a closed space 22C formed between the inner plate 18 and the guide frame 22A of the inner guide 22, and a closed space 23C formed between the outer plate 19 and the guide frame 23A of the outer guide 23, It is formed as a closed space having substantially the same cross-sectional area, and is between a closed space 22D formed between the inner plate 18 and the guide frame 22B of the inner guide 22, and between the outer plate 19 and the guide frame 23B of the outer guide 23. The formed closed space 23D can be formed as a closed space having substantially the same cross-sectional area.

  As a result, the cross-sectional strength of the inner plate 18 fixed to the connecting flange 16 and the cross-sectional strength of the outer plate 19 can be made uniform, and when the excavator 1 performs left turn traveling and right turn traveling, Since one of the plate 18 and the outer plate 19 can be prevented from being twisted, the durability of the idler wheel bracket 17 can be enhanced, and the stability of the excavator 1 during travel can be enhanced.

  Further, by forming the inner plate 18 and the outer plate 19 of the idler wheel bracket 17 symmetrically in the left and right directions around the idler wheel 6, as shown in FIG. 5, the outer plate 19 (rising plate 19A) is formed. A step 20 having a dimension L larger than the plate thickness dimension T of the connection flange 16 is formed between the corner 19C where the outer plate 19B intersects with the corner 15E of the side frame body 15. Can do.

  Therefore, due to the tension of the crawler belt 8 wound around the idler wheel 6 and the drive wheel 7, the load in the direction indicated by the arrow F1 from the corner corner portion 15E of the side frame body 15 toward the connection flange 16 as shown in FIG. When the load in the direction of arrow F2 acts from the corner corner 19C of the outer plate 19 constituting the idler wheel bracket 17 toward the connection flange 16, the load acting on the connection flange 16 from the corner corner 15E. The distance (the dimension L of the stepped portion 20) between the acting point P1 and the acting point P2 of the load acting on the connecting flange 16 from the corner 19C can be kept at a relatively large value.

  As a result, an arrow F1 direction load acting on the connection flange 16 from the corner corner 15E of the side frame body 15 and an arrow acting on the connection flange 16 from the corner corner 19C of the outer plate 19 constituting the idler wheel bracket 17 are shown. The shear stress acting on the connection flange 16 due to the load in the direction F2 can be reduced, and the durability of the connection flange 16 can be increased.

  In the embodiment described above, the case where the upper connecting plate 21 connects the inner upper plate 18B of the inner plate 18 and the outer upper plate 19B of the outer plate 19 constituting the idler wheel bracket 17 is illustrated. . However, the present invention is not limited to this. For example, as in the modification shown in FIG. 9, the upper end of the inner upper plate 18B ′ extends toward the outer plate 19 and the upper end of the outer upper plate 19B ′ extends to the inner plate 18. The upper end portion of the inner upper plate 18B ′ and the upper end portion of the outer upper plate 19B ′ may be fixed to each other at the left and right center portions by means of welding or the like.

  Moreover, in embodiment mentioned above, the hydraulic excavator 1 is mentioned as an example and demonstrated as a tracked vehicle. However, the present invention is not limited to this, and can be widely applied to other tracked vehicles such as a hydraulic crane.

1 Hydraulic excavator (tracked vehicle)
6 idler wheel 7 drive wheel 11 track frame 12 center frame 14 side frame 15 side frame main body 15A inner surface plate 15B outer surface plate 15C upper surface plate 15E, 19C corner corner 16 connection flange 17 idler wheel bracket 18 inner plate 18B, 18B 'inner upper Plate 19 Outer plate 19B, 19B 'Outer upper plate 20 Stepped portion 25 Other connecting flange 26 Drive wheel bracket

Claims (5)

A center frame and a side frame attached to the center frame via left and right legs and extending in the front and rear directions;
The side frame includes a side frame main body positioned at a front and rear center portion, and an idler wheel bracket provided on one side of the front and rear directions of the side frame main body via a connection flange to which an idler wheel is attached, It is constituted by a drive wheel bracket that is provided via another connection flange on the other side of the front and rear direction of the side frame main body and to which a drive wheel is attached,
The side frame body includes an inner surface plate attached to the leg portion, an outer surface plate facing the inner surface plate in the left and right directions, and a connection between the inner surface plate and the upper end portion of the outer surface plate. And an upper surface plate inclined obliquely downward toward the
The idler wheel bracket includes an inner plate disposed on the center frame side with the idler wheel interposed therebetween and provided with an inner upper plate on the upper end side, and an upper end disposed on the opposite side of the center frame with the idler wheel interposed therebetween. In a track frame of a tracked vehicle constituted by an outer plate provided with an outer upper plate on the side,
The inner upper plate of the inner plate forms an inclined surface that is inclined obliquely downward from the idler wheel toward the inner plate, and the outer upper plate of the outer plate is inclined toward the outer plate from the idler wheel. A track frame for a tracked vehicle characterized by forming an inclined surface inclined downward.   The side frame main body and the idler wheel bracket are disposed between a corner corner where the outer surface plate and the upper surface plate of the side frame body intersect and a corner corner where the outer plate and the outer upper plate of the idler wheel bracket intersect. The track frame of a track type vehicle according to claim 1, wherein stepped portions having dimensions larger than the plate thickness dimensions of the connection flanges to be connected to each other are formed.   A step portion formed between a corner portion where the outer surface plate and the upper surface plate of the side frame body intersect and a corner portion where the outer plate and the outer upper plate of the idler wheel bracket intersect with each other is formed of the connection flange. The track frame of a tracked vehicle according to claim 2, wherein the track frame is set to a dimension that is not less than 2 times and not more than 5 times the plate thickness dimension.   4. The track frame for a tracked vehicle according to claim 1, wherein the inner plate and the outer plate of the idler wheel bracket are formed symmetrically in the left and right directions across the idler wheel. The inner upper plate and the outer upper plate of the idler wheel bracket are connected by an upper connecting plate extending in the left and right directions at a position adjacent to the connection flange,
The upper connecting plate is configured to incline in a mountain shape so as to be symmetrical in the left and right directions from the left and right central portions toward the inner and outer plates of the idler bracket. 5. A track frame for a tracked vehicle according to 3 or 4.

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