JPWO2012026233A1 - Construction machinery - Google Patents

Abstract

The turning frame (11) includes a center frame (12) and a tail frame (30). Further, the center frame (12) is erected on the front bottom plate (13) and the front bottom plate (13), and the front side pins the lower boom (5A) and the boom cylinder (5E) of the work device (5). The left and right front vertical plates (14, 17) are the right bracket portions (14A, 17A). The tail frame (30) is composed of left and right I-type beams (31, 32) and a rear bottom plate (33) connecting the I-type beams (31, 32). The height dimension (A) of the boom pin insertion hole (15A, 18A) provided in the bracket portion (14A, 17A) is set to the height of the upper flange portion (31B, 32B) of the I-shaped beam (31, 32). Set smaller than the height dimension (B).

Description

  The present invention relates to a construction machine such as a hydraulic excavator, and more particularly to a construction machine including a turning frame formed by connecting a tail frame to the rear side of a center frame.

  Generally, a hydraulic excavator, which is a typical example of a construction machine, includes a self-propelled lower traveling body, an upper revolving body that is turnably mounted on the lower traveling body and forms a vehicle body with the lower traveling body, and the upper swivel It is mainly constituted by a working device provided on the front side of the body so as to be able to move up and down.

  The upper swing body includes a swing frame, a cab provided on the front left side of the swing frame, an engine and a hydraulic pump mounted on the rear side of the swing frame, a building cover that covers the engine, and the like. And a counterweight attached to the rear end.

  The revolving frame of the upper revolving structure includes, for example, a center frame constituting a central portion of the revolving frame, a tail frame connected to the rear side of the center frame, and left and right directions with the center frame and the tail frame interposed therebetween. It is comprised by the left and right side frame provided in both sides (patent document 1).

  In this case, the center frame of the revolving frame is, for example, a front bottom plate, and extends in the front and rear directions on the front bottom plate and is erected with a gap in the left and right directions, and the front side is connected to the boom and boom cylinder of the working device. It consists of left and right front vertical plates that serve as a bracket for pin connection. On the other hand, the tail frame is composed of left and right I-type beams joined to the rear part of each front vertical plate, and a rear bottom plate connecting the I-type beams.

  The left and right I-shaped beams of the tail frame are provided on the upper side of the left and right rear vertical plates, which extend in the front and rear directions and the front ends are joined to the front vertical plates, and on the front of the rear vertical plates, It is formed by an upper flange portion extending in the rear direction and having a front end joined to each front vertical plate, and a lower flange portion provided on the lower side of each rear vertical plate and extending in the front and rear directions and having the front end joined to the front bottom plate. ing.

  Further, the bracket portion of the center frame is provided with a boom pin insertion hole for pin coupling the foot portion (base end portion) of the boom and a cylinder pin insertion hole for pin coupling the base end portion of the boom cylinder. Yes. The foot part of the boom is pivotably attached to the bracket part of the center frame via a boom connecting pin inserted through the boom pin insertion hole, and the base end part of the boom cylinder is a cylinder pin. It is rotatably attached to the bracket portion of the center frame via a cylinder connecting pin inserted through the insertion hole.

  By the way, in order to effectively use the force of the boom cylinder, it is preferable to increase the distance between the foot portion of the boom and the base end portion of the boom cylinder. In order to increase this distance, the height dimension from the front bottom plate of the center frame to the foot of the boom, that is, the height dimension from the front bottom plate of the center frame to the center of the hole of the boom pin insertion hole must be increased. Can be considered. In this case, it is necessary that the left and right front vertical plates including the bracket portion have sufficient strength so as to withstand the torsional moment applied from the boom.

  On the other hand, Patent Document 2 discloses a configuration in which the strength of the left and right front vertical plates can be ensured by providing a reinforcing member between the left and right front vertical plates and the front bottom plate. . Further, in Patent Document 3, the front side of the left and right vertical plates (center beam) is configured in a box shape so that the strength of the front side of the left and right vertical plates can be secured. A configuration is disclosed.

JP 2001-342646 A JP 10-37244 A JP-A-8-165679

  In the prior art according to Patent Document 2, there is a concern that the weight of the swivel frame increases as the reinforcing member is provided. On the other hand, in the prior art according to Patent Document 3, the front side of the left and right vertical plates (center beams) is formed in a box shape, so that the structure becomes complicated, resulting in an increase in size and weight. .

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a construction machine capable of configuring a center frame of a revolving frame to be small and light.

  (1). In order to solve the above-described problems, the present invention is provided with a lower traveling body, an upper revolving body that is turnably mounted on the lower traveling body, and a front and rear side of the upper revolving body that can be raised and lowered. A center frame of a revolving frame that constitutes the upper revolving structure, and has a front bottom plate, and extends in the front and rear directions on the front bottom plate, and is erected at intervals in the left and right directions, and the front side is A tail frame connected to the rear side of the center frame is formed by a left and right front vertical plate which is a bracket portion that pin-couples a boom and a boom cylinder of the work device, and a rear portion of each front vertical plate. And left and right I-type beams and rear bottom plates connecting the I-type beams. The left and right I-type beams extend in the front and rear directions, and the front ends thereof are respectively Left and right rear vertical plates joined to the front vertical plate, and the respective rear vertical plates An upper flange portion provided on the upper side and extending in the front and rear directions and having a front end joined to each front vertical plate, and provided on the lower side of each rear vertical plate and extending in the front and rear directions, and the front end joined to the front bottom plate. It is applied to a construction machine formed by a lower flange portion.

  A feature of the configuration adopted by the present invention is that the bracket portion of the center frame is provided with a boom pin insertion hole for pin-connecting the foot portion of the boom, and from the front bottom plate to the hole center of the boom pin insertion hole. The height dimension (A) is smaller than the height dimension (B), where (A) is the height dimension and (B) is the height dimension from the front bottom plate to the front end of the upper flange portion. It is in setting.

  According to this configuration, the height dimension from the front bottom plate to the foot portion of the boom can be reduced, and the torsional moment, bending moment, and the like applied from the boom to the left and right front vertical plates can be reduced accordingly. Therefore, it is necessary to provide a reinforcing member between the left and right front vertical plates and the front bottom plate as in the prior art, or to configure the front side of the left and right vertical plates (center beam) in a box shape. The center frame can be made small and lightweight. In addition, since the height position of the foot portion of the boom can be lowered, the height dimension of the construction machine as a whole can also be lowered. Therefore, for example, even when a trailer loaded with construction machines travels on a public road, this height dimension can be easily kept within a range regulated by laws and the like.

  (2). In the bracket portion of the center frame, a cylinder pin insertion hole for pin-coupling the boom cylinder is provided at a position on the front side and the lower side of the boom pin insertion hole, and the height When the dimension (A) is set smaller than the height dimension (B), the distance between the center of the cylinder pin insertion hole and the center of the boom pin insertion hole is (C) and the horizontal direction (D), and for comparison, the height dimension (Ap) from the front bottom plate to the center of the boom pin insertion hole is larger than the height dimension (Bp) from the front bottom plate to the front end of the upper flange. When the distance between the center of the cylinder pin insertion hole and the center of the boom pin insertion hole is (Cp) and the distance in the horizontal direction is (Dp), the distance (C) Is the separation dimension (C The distance (D) is set to be larger than the distance (Dp) so as to correspond to the height dimension (A) lower than the height dimension (Ap) so as to be equal to p). It is to have done.

  According to this configuration, the hole center of the cylinder pin insertion hole and the hole center of the boom pin insertion hole correspond to the amount of the height dimension (A) from the front bottom plate to the hole center of the boom pin insertion hole being lowered. Since the distance (D) in the horizontal direction is set to be large, it is possible to secure a separation dimension (C) between the hole center of the cylinder pin insertion hole and the hole center of the boom pin insertion hole. Thereby, even when the height dimension (A) from the front bottom plate to the hole center of the boom pin insertion hole is lowered, the distance between the foot portion of the boom and the base end portion of the boom cylinder can be secured. The force of the boom cylinder can be used effectively.

  (3). In the present invention, when the height dimension (A) is set smaller than the height dimension (B), the center line in the front and rear directions (S-) passing through the middle between the left front vertical plate and the right front vertical plate of the center frame. S) is the distance between the center frame turning center (O) and (E). As a comparison object, the height dimension (Ap) from the front bottom plate to the center of the boom pin insertion hole is the upper flange portion. Before passing through the middle of the left front vertical plate and the right front vertical plate of the center frame when it is larger than the height dimension (Bp) to the front end of the center frame (Sp-Sp) and the center frame turning center (Op) ) Is set to be smaller than the distance (Ep), where (Ep) is the distance.

  According to this configuration, the distance (E) between the center line (SS) in the rear direction and the turning center (O) of the center frame is set small before passing through the middle between the left front vertical plate and the right front vertical plate. Further, the left front and right front plates can be evenly approached in the left and right directions with respect to the turning wheel provided between the upper turning body and the lower traveling body. As a result, the turning wheel can receive the force applied from the left and right front vertical plates via the front bottom plate in a state that is closer to the left and right directions, and can reduce the twist of the center frame ( It can be advantageously constructed in terms of strength).

  (4). According to the present invention, the bracket portion of the center frame is provided with a cylinder pin insertion hole for pin coupling the boom cylinder at a position in front of and below the boom pin insertion hole. When the height dimension (A) is set smaller than the height dimension (B), the distance between the center of the cylinder pin insertion hole and the center of the boom pin insertion hole is (C), and the horizontal direction (D) and the distance between the center line (SS) of the center frame before and after passing through the middle of the left front vertical plate and the right front vertical plate of the center frame and the turning center (O) of the center frame (E), and for comparison, the height dimension (Ap) from the front bottom plate to the center of the boom pin insertion hole is larger than the height dimension (Bp) from the front bottom plate to the front end of the upper flange. Cylinder pin insertion The distance between the hole center and the boom pin insertion hole center is (Cp), the horizontal distance is (Dp), and the center frame before passing through the middle between the left front vertical plate and the right front vertical plate. , Where the distance between the center line (Sp-Sp) in the rear direction and the center of rotation (Op) of the center frame is (Ep), the separation dimension (C) is approximately the same as the separation dimension (Cp). Thus, the distance (D) is set to be larger than the distance (Dp) corresponding to the height dimension (A) being lower than the height dimension (Ap), and the distance (D It is preferable to set E) to be smaller than the distance (Ep). As a result, the same effects as in the items (2) and (3) can be obtained.

  (5). Further, the present invention provides a front plate extending in the left and right directions and connecting the left and right front vertical plates on the front side between the left and right front vertical plates, Has a configuration in which a first bent portion and a second bent portion bent at two locations in the front and rear directions are provided.

  According to this configuration, the front plate connecting the front side between the left and right front vertical plates is configured to be folded at two locations, so that the strength of the front plate is improved as compared with the case of folding at one location. In addition, the degree of freedom in design such as the inclination angle of the front plate and the positional relationship of the front end portion (lower end portion) of the front plate with respect to the turning wheel can be increased.

1 is a front view showing a hydraulic excavator according to an embodiment of the present invention. It is a top view which shows a turning frame alone. It is a front view shown in the state which attached the turning wheel to the turning frame shown in FIG. It is a front view shown in the state which attached the turning wheel and the working apparatus to the turning frame shown in FIG. It is a right view of FIG. 2 which shows a turning frame alone. It is a perspective view which shows a turning frame. It is a disassembled perspective view which shows a turning frame. It is a front view which shows a center frame. It is a top view of FIG. 8 which shows a center frame. It is a front view which shows the center frame by a comparative example. It is a top view of FIG. 10 which shows the center frame by a comparative example.

  Hereinafter, an embodiment of a construction machine according to the present invention will be described in detail with reference to the accompanying drawings, taking as an example a case where the construction machine is applied to a hydraulic excavator.

  In the figure, reference numeral 1 denotes a wheel-type hydraulic excavator which is a typical example of a construction machine. The hydraulic excavator 1 includes a wheel-type lower traveling body 2 capable of self-propelling and a swiveling wheel 3 on the lower traveling body 2. The upper revolving body 4 that is mounted so as to be able to turn and constitutes the vehicle body together with the lower traveling body 2 and the working device 5 that is provided on the front side of the upper revolving body 4 so as to be able to move up and down are roughly constituted. This wheel-type hydraulic excavator 1 travels on a general road by a wheel-type lower traveling body 2, and performs excavation work of earth and sand using a work device 5 at a work site.

  Here, the lower traveling body 2 includes a track frame 2A to which the turning wheel 3 is attached on the upper surface side, and a front and rear wheels 2B provided on the track frame 2A and driven by a hydraulic motor (not shown). It is configured. The lower traveling body 2 is configured to travel on public roads, work sites, and the like by driving the wheels 2B.

  The upper turning body 4 is provided on a left side of the front part of the turning frame 11 and a turning frame 11 (described later) mounted on the track frame 2A of the lower traveling body 2 via a turning wheel 3 so as to be turnable. A counterweight 7 provided on the rear end side of the cab 6 and the swing frame 11 for balancing the weight of the working device 5; an engine and a hydraulic pump provided on the front side of the counterweight 7 (not shown) And a hydraulic oil tank 9 and a fuel tank 10 provided on the front side of the building cover 8.

  Further, the working device 5 is attached to a lower boom 5A as a boom whose base end side is rotatably attached to the front side of the revolving frame 11, and to the distal end side of the lower boom 5A. An upper boom 5B, an arm 5C rotatably attached to the distal end side of the upper boom 5B, a bucket 5D rotatably attached to the distal end side of the arm 5C, and left and right boom cylinders 5E (right side) Only, and a cylinder including a positioning cylinder 5F, an arm cylinder 5G, and a bucket cylinder 5H.

  Next, the structure of the turning frame 11 used in this embodiment will be described. In the present embodiment, the turning frame 11 is composed of four parts, and each part is integrally joined to form one frame.

  That is, as shown in FIGS. 2 to 7, the revolving frame 11 has a center frame 12 positioned at the center front side, a tail frame 30 positioned at the center rear side, and the left side of the center frame 12 and the tail frame 30. The left side frame 35 is positioned, and the right side frame 39 is also positioned on the right side.

  Reference numeral 12 denotes a center frame that constitutes a central portion of the revolving frame 11, and the center frame 12 extends on the front bottom plate 13 in the front and rear directions, and stands in the left and right directions with an interval therebetween. The left front vertical plate 14, the right front vertical plate 17 and the front vertical plates 14 and 17 which are provided are positioned on the front side of the front vertical plates 14 and 17 and extend in the left and right directions. A front plate 20 and a left cylinder mounting plate 21 and a right cylinder mounting plate 22 which are located on the front side of the front plate 20 and extend in the front and rear directions and are erected on the front bottom plate 13 at intervals in the left and right directions. It is roughly structured.

  Reference numeral 13 denotes a front bottom plate 13 of the center frame 12. The front bottom plate 13 is made of, for example, a thick steel plate having a substantially rectangular shape, and the revolving wheel 3 is attached to the lower surface side thereof. For this purpose, as shown in FIG. 9, the front bottom plate 13 is provided with a plurality of bolt insertion holes 13A on the same circumference around the turning center O, and mounting bolts inserted into the respective bolt insertion holes 13A. It is the structure which attaches the turning ring | wheel 3 to the lower surface side of the front bottom board 13 using (not shown).

  Further, the front bottom plate 13 is provided with a center hole 13B through which a center joint (not shown) is inserted at a portion corresponding to the turning center O. A swivel device mounting hole 13C to which a swivel device (not shown) is mounted is provided on the rear side of the center hole 13B.

  Next, the left front vertical plate 14 constituting a part of the center frame 12 will be specifically described.

  Reference numeral 14 denotes a left front vertical plate that is positioned on the left side on the front bottom plate 13 and is erected substantially vertically so as to extend in the front and rear directions. The left front vertical plate 14 has a mountain shape in which the front and rear center portions protrude upward, and the front side pin-couples a lower boom 5A and a left boom cylinder (not shown) of the work device 5 to be described later. It is a bracket portion 14A.

  The left bracket portion 14A is located on the front side of the left front vertical plate 14 and is used for pin coupling the lower boom 5A and the left boom cylinder. For this reason, the left bracket portion 14 </ b> A includes a left boom mounting plate portion 15 described later and a left cylinder mounting plate portion 16.

  Reference numeral 15 denotes a left boom mounting plate portion located at an upper portion of the bracket portion 14A of the left front vertical plate 14, and the left boom mounting plate portion 15 uses a foot portion (base end portion) of the lower boom 5A as a boom connecting pin described later. 27 is rotatably supported (pin-coupled). Therefore, the left boom mounting plate portion 15 has a left boom pin insertion hole 15A through which the boom connecting pin 27 is inserted on the same axis as a right boom pin insertion hole 18A of the right boom mounting plate portion 18 described later. Is provided.

  Here, the left boom pin insertion hole 15 </ b> A is provided at a position lower than the front end of the upper flange portion 31 </ b> B of the I-shaped beam 31 constituting the tail frame 30 described later. That is, as shown in FIGS. 3 and 8, the height dimension from the front bottom plate 13 to the hole center of the left boom pin insertion hole 15A is A, and the height dimension from the front bottom plate 13 to the front end of the upper flange portion 31B. Is set to B, the height dimension A is set smaller than the height dimension B, as shown in the following formula 1. Thereby, the height dimension from the front bottom board 13 to the foot part of the lower boom 5A can be made low, and the torsional moment, bending moment, etc. which are applied to the left front vertical board 14 from this lower boom 5A can be suppressed.

  Reference numeral 16 denotes a left cylinder mounting plate portion that constitutes the left bracket portion 14A of the left front vertical plate 14 together with the left boom mounting plate portion 15. The left cylinder mounting plate portion 16 is located on the front side and lower side of the left boom mounting plate portion 15. Is located. The left cylinder mounting plate portion 16 supports (pin-couples) the base end portion (bottom portion) of the left boom cylinder so as to be rotatable via a connecting pin for a left cylinder (both not shown). Here, a pair of left cylinder pin insertion holes 16 </ b> A and 21 </ b> A are formed on the left cylinder mounting plate 16 and a later-described left cylinder mounting plate 21 provided facing the left bracket portion 14 </ b> A of the left front vertical plate 14. They are provided on the same axis. These left cylinder pin insertion holes 16A and 21A support the left boom cylinder via a left cylinder connecting pin.

  Next, the right front vertical plate 17 constituting a part of the center frame 12 will be specifically described.

  Reference numeral 17 denotes a right front vertical plate provided on the front bottom plate 13 with a left and right spacing between the left front vertical plate 14. The front right vertical plate 17 is located on the right side of the front bottom plate 13 and is erected substantially vertically so as to extend in the front and rear directions. Like the left front vertical plate 14, the right front vertical plate 17 has a mountain shape with the front and rear central portions protruding upward, and the front side includes the lower boom 5 </ b> A and the right boom cylinder 5 </ b> E of the work device 5. It is a right bracket portion 17A for pin connection. That is, the right bracket portion 17A includes a right boom mounting plate portion 18 and a right cylinder mounting plate portion 19 which will be described later.

  Reference numeral 18 denotes a right boom mounting plate portion located at an upper portion of the right bracket portion 17A of the right front vertical plate 17, and the right boom mounting plate portion 18 connects a foot portion (base end portion) of the lower boom 5A to a boom connection described later. A pin 27 is rotatably supported (pin coupled). For this purpose, the right boom mounting plate portion 18 is provided with a right boom pin insertion hole 18A for inserting the boom connection pin 27 on the same axis as the left boom pin insertion hole 15A of the left boom mounting plate portion 15. It has been.

  Here, as with the left boom pin insertion hole 15A, the right boom pin insertion hole 18A is also provided at a position lower than the front end of the upper flange portion 32B of the I-shaped beam 32 constituting the tail frame 30 described later. Yes. That is, as shown in FIGS. 3 and 8, the height dimension from the front bottom plate 13 to the hole center of the right boom pin insertion hole 18A is A, and the height dimension from the front bottom plate 13 to the front end of the upper flange portion 32B. Is set to B, the height dimension A is set to be smaller than the height dimension B, as shown in Equation 1 above. Thereby, the height dimension from the front bottom board 13 to the foot part of the lower boom 5A can be made low, and the torsional moment, bending moment, etc. which are applied to the right front vertical board 17 from this lower boom 5A can be suppressed.

  Reference numeral 19 denotes a right cylinder mounting plate portion which constitutes a right bracket portion 17A of the right front vertical plate 17 together with the right boom mounting plate portion 18. The right cylinder mounting plate portion 19 is located on the front side and the lower side of the right boom mounting plate portion 18. Is located. The right cylinder mounting plate portion 19 supports (pin-couples) the base end portion (bottom portion) of the right boom cylinder 5E so as to be rotatable via a right cylinder connecting pin 28 described later. Here, the right cylinder mounting plate portion 19 and the right cylinder mounting plate 22 described later have a pair of right cylinder pin insertion holes 19A, 22A on the same axis and the left cylinder pin insertion holes 16A, 21A is also provided on the same axis. These right cylinder pin insertion holes 19A, 22A support the right boom cylinder 5E via the right cylinder connecting pin 28.

  Next, 20 is a front plate that is located on the front side of the front bottom plate 13 and connects the left and right front vertical plates 14 and 17, and the front plate 20 constitutes a part of the center frame 12. . Here, the front plate 20 is formed as a trihedral plate that is bent at two locations in the front and rear directions, for example, by bending a plate material such as a steel plate.

  Specifically, the front plate 20 includes a front surface portion 20A that rises vertically from the front bottom plate 13, and a first bent portion 20B that is located on the upper end side of the front surface portion 20A and is bent toward the rear side. The first inclined portion 20C that is continuous with the front surface portion 20A via the first bent portion 20B, and the second inclined portion that is located on the upper end side of the first inclined portion 20C and is bent toward the front side. It is comprised by the bending part 20D and the 2nd inclination part 20E which follows the 1st inclination part 20C via this 2nd bending part 20D. In the front plate 20, the lower end edge of the front surface portion 20 </ b> A is joined to the upper surface of the front bottom plate 13 using welding means, the left end edge is joined to the inner surface of the left front vertical plate 14, and the right end edge is the inner side of the right front vertical plate 17. It is joined to the side.

  On the other hand, an opening 20F is formed in the front plate 20 across the front surface portion 20A and the first inclined portion 20C, and the opening 20F is, for example, an opening for passing a hydraulic hose (not shown) for the working device 5 It has become. In addition, left and right cylinder mounting plates 21 and 22, which will be described later, are joined to the front surface of the front plate 20 over the front surface portion 20A and the first inclined portion 20C.

  Reference numeral 21 denotes a left cylinder mounting plate provided on the left side of the front surface of the front plate 20. The left cylinder mounting plate 21 extends in the front and rear directions and is erected from the front bottom plate 13 to the first inclined portion 20C of the front plate 20. ing. The left cylinder mounting plate 21 faces the left cylinder mounting plate portion 16 provided on the left bracket portion 14A of the left front vertical plate 14.

  Here, the left cylinder mounting plate 21 is joined to the upper left side of the front bottom plate 13 and the front left side of the front plate 20 using welding means. The front end portion of the left cylinder mounting plate 21 is provided with a left cylinder pin insertion hole 21A for inserting a left cylinder connecting pin. The left cylinder pin insertion hole 21 </ b> A is disposed so as to face the left cylinder pin insertion hole 16 </ b> A provided in the left cylinder mounting plate 16.

  Reference numeral 22 denotes a right cylinder mounting plate provided on the front right side of the front plate 20, and the right cylinder mounting plate 22 extends in the front and rear directions in the same manner as the left cylinder mounting plate 21 described above and extends from the front bottom plate 13 to the front plate 20. The first inclined portion 20C is erected. The right cylinder mounting plate 22 faces the right cylinder mounting plate portion 19 and is joined to the right upper surface of the front bottom plate 13 and the front right side of the front plate 20 using welding means. The front end of the right cylinder mounting plate 22 is provided with a right cylinder pin insertion hole 22A for inserting the right cylinder connecting pin 28. The right cylinder pin insertion hole 22A is connected to the right cylinder pin insertion hole 19A. It is arranged facing each other.

  Reference numerals 23 and 24 denote outer reinforcing plates provided on the outer surfaces of the front portions of the left and right front vertical plates 14 and 17, respectively. The outer reinforcing plates 23 and 24 are respectively provided to the left and right front vertical plates 14 and 17. Of these, the boom pin insertion holes 15A, 18A and the cylinder pin insertion holes 16A, 19A are joined to the outer surface of the part (the parts to become the left and right bracket portions 14A, 17A), and the thickness of the part Is to increase.

  Reference numerals 25 and 26 denote inner reinforcing plates respectively provided on the inner inner surfaces of the upper portions of the left and right front vertical plates 14 and 17. The inner reinforcing plates 25 and 26 correspond to the left and right front vertical plates 14 and 17, respectively. Among them, it is joined to the inner side surface of the portion where the boom pin insertion holes 15A, 18A are formed (the portions to be the left and right boom mounting plate portions 15, 18), and the thickness of the portion is increased.

  Reference numeral 27 denotes a boom connecting pin for rotatably supporting the foot part of the lower boom 5A on the left and right boom mounting plate parts 15 and 18, and the boom connecting pin 27 is inserted into the left and right boom pins. It is inserted through the holes 15A and 18A.

  28 is a bottom right cylinder connecting pin for rotatably supporting the base end (bottom) of the right boom cylinder 5E between the right cylinder mounting plate 19 and the right cylinder mounting plate 22. The right cylinder connecting pin 28 is inserted into the right cylinder pin insertion holes 19A, 22A. Reference numeral 29 denotes a rod-side right cylinder connecting pin that rotatably supports the tip end side (rod side) of the right boom cylinder 5E on the lower boom 5A.

  Next, reference numeral 30 denotes a tail frame connected to the rear side of the center frame 12. The tail frame 30 is generally composed of left and right I-shaped beams 31 and 32, a rear bottom plate 33, and a pair of horizontal plates 34, which will be described later.

  Reference numerals 31 and 32 denote left and right I-type beams connected to the left and right front vertical plates 14 and 17 and the front bottom plate 13 of the center frame 12, respectively. It is formed in a letter shape. These I-type beams 31 and 32 are arranged on the rear side of the left and right front vertical plates 14 and 17 so as to extend in the front and rear directions with an interval in the left and right directions.

  Here, the left I-shaped beam 31 includes a left rear vertical plate 31A extending in the front and rear directions, and an upper flange portion that is joined to the upper end edge of the left rear vertical plate 31A using welding means and extends in the front and rear directions. It is formed by 31B and the lower flange part 31C which is joined to the lower end edge of the left rear vertical board 31A using a welding means and extends in the front and rear directions. Similarly, the right I-shaped beam 32 is formed by a right rear vertical plate 32A, an upper flange portion 32B, and a lower flange portion 32C in the same manner as the left I-shaped beam 31.

  The front end side of the tail frame 30 is connected to the rear end portion of the center frame 12 by welding means. For this purpose, the front edge of each rear vertical plate 31A, 32A is the rear edge of each front vertical plate 14, 17, and the front end of each upper flange 31B, 32B is the rear end of each front vertical plate 14, 17. On the upper surface side, the front end edges of the lower flange portions 31C and 32C and the front end edge of the rear bottom plate 33 described later are joined to the rear end edge of the front bottom plate 13, respectively. Here, in a state where the tail frame 30 and the center frame 12 are connected, the height dimension B of the front ends of the upper flange portions 31B and 32B is larger than the height dimension A of the boom pin insertion holes 15A and 18A. (See Equation 1).

  Reference numeral 33 denotes a rear bottom plate that connects the lower ends of the left and right I-shaped beams 31 and 32. The rear bottom plate 33 is formed in a flat plate shape with a steel plate or the like, and the lower flange portions 31C of the I-shaped beams 31 and 32 are provided. It is joined to 32C using welding means. Two openings 33A and 33B are formed in the rear bottom plate 33, and maintenance of equipment mounted on the engine or the like can be performed from the lower side of the upper swing body 4 through the openings 33A and 33B.

  Reference numeral 34 denotes a pair of horizontal plates that connect the I-type beams 31 and 32 at two positions in the middle of the left and right I-type beams 31 and 32. Each of the horizontal plates 34 is formed into a flat plate shape by a steel plate or the like. And is joined to the upper surface of the rear bottom plate 33 and the vertical plates 31A and 32A, the upper flange portions 31B and 32B, and the lower flange portions 31C and 32C of the I-type beams 31 and 32 using welding means. Each of these horizontal plates 34 is provided with a total of four engine support brackets 34A (see FIGS. 2 to 4), and each engine support bracket 34A has an anti-vibration mount (not shown). The engine is supported via

  Reference numeral 35 denotes a left side frame which is attached to the left side of the center frame 12 and the tail frame 30. The left side frame 35 has a D-shaped cross section and extends in the front and rear directions, and the left D frame 36 and the left D frame 36. And a plurality of left extending beams 37 provided between the center frame 12 and the tail frame 30 and extending in the left and right directions, a cab support frame 38 for supporting the cab 6, and the like.

  Reference numeral 39 denotes a right side frame attached to the right side position of the center frame 12 and the tail frame 30. The right side frame 39 has a D-shaped cross section and extends in the front and rear directions. The right D frame 40 and the right D frame 40 The center frame 12 and the tail frame 30 are provided with a plurality of right extending beams 41 extending leftward and rightward.

  Next, the configuration of the center frame 12 used in the present embodiment will be described in comparison with the configuration of the comparative example shown in FIGS. In the comparative example, a dash (′) is added to the configuration corresponding to the present embodiment, and the description thereof is omitted.

  The center frame 12 'of the comparative example shown in FIGS. 10 and 11 constitutes the tail frame 30' with the boom pin insertion holes 15A 'and 18A' of the left and right boom mounting plate portions 15 'and 18'. It is provided at a position higher than the front ends of the upper flange portions 31B 'and 32B' of the I-shaped beams 31 'and 32'. That is, in the case of the comparative example, the height dimension from the front bottom plate 13 'to the hole center of the boom pin insertion holes 15A', 18A 'is Ap, and the front end of the upper flange portions 31B', 32B 'from the front bottom plate 13'. Assuming that the height dimension up to Bp is Bp, the height dimension Ap is set larger than the height dimension Bp as shown in Equation 2 below.

  On the other hand, in the case of the present embodiment, as shown in FIGS. 3 and 8, the height dimension from the front bottom plate 13 to the hole center of the boom pin insertion holes 15A, 18A is A, and from the front bottom plate 13 When the height dimension to the front end of the upper flange portions 31B and 32B is B, the height dimension A is set smaller than the height dimension B as shown in the above equation (1).

  Further, in the case of the present embodiment, the distance between the center of the left and right cylinder pin insertion holes 16A, 21A, 19A, 22A and the center of the boom pin insertion holes 15A, 18A is C. Let D be the horizontal distance. In this case, in the present embodiment, the horizontal distance D is set larger than the horizontal distance Dp in the configuration of the comparative example shown in FIGS. Yes.

  That is, as shown in FIG. 10, the distance between the center of the left and right cylinder pin insertion holes 16A 'and 19A' and the center of the boom pin insertion holes 15A 'and 18A' in the comparative example is Cp. And the horizontal distance is Dp. In this case, the horizontal distance D according to the present embodiment shown in FIG. 8 is set to be larger than the horizontal distance Dp according to the comparative example (see Expression 3).

  Specifically, even if the height dimension A according to the present embodiment is lower than the height dimension Ap according to the comparative example, the separation dimension C according to the present embodiment is approximately the same as the separation dimension Cp according to the comparative example. Is set. That is, in the present embodiment, the horizontal distance D is set to be larger than the horizontal distance Dp according to the comparative example corresponding to the height dimension A lower than the height dimension Ap (several numbers). 3).

  Thus, in the present embodiment, even if the height dimension A from the front bottom plate 13 to the hole center of the boom pin insertion holes 15A, 18A is lowered, the foot part of the lower boom 5A and the base end part of each boom cylinder 5E (The distance C) can be increased, and the force of each boom cylinder 5E can be used effectively.

  Furthermore, as shown in FIG. 9, in the present embodiment, the center line SS before and behind the center frame 12 passes through the middle of the left front vertical plate 14 and the right front vertical plate 17 and the center of rotation O of the center frame 12. And E (the distance in the horizontal direction). In this case, in this embodiment, the distance E is set smaller than the distance Ep of the configuration of the comparative example shown in FIGS.

  That is, as shown in FIG. 11, in the comparative example, the center line Sp-Sp of the center frame 12 'and the center frame 12' turn before and after passing through the middle of the left front vertical plate 14 'and the right front vertical plate 17'. A distance from the center Op (horizontal interval) is set to Ep. In this case, the distance E according to the present embodiment shown in FIG. 9 is set smaller than the distance Ep according to the comparative example (see Expression 4).

  Thereby, in this Embodiment, the engagement (positional relationship) of the left front vertical board 14 and the right front vertical board 17 with respect to the turning wheel 3 can be approached equally in the left and right directions, and the twist of the center frame 12 can be reduced. Can do.

  The hydraulic excavator 1 according to the present embodiment has the above-described configuration. The hydraulic excavator 1 travels on a general road or the like by the lower traveling body 2 and thus self-travels to the work site, and then the upper swing body 4. The excavation work of earth and sand is performed by moving the working device 5 up and down while turning.

  Here, when excavation work or the like is performed by the work device 5, a large load such as excavation reaction force is applied to the left and right front vertical plates 14 and 17 of the center frame 12 that supports the work device 5. In contrast, the center frame 12 according to the present embodiment has a height dimension A from the front bottom plate 13 to the center of the boom pin insertion holes 15A, 18A, and the upper flanges of the I-shaped beams 31, 32 from the front bottom plate 13. It is set smaller than the height dimension B to the front ends of the portions 31B and 32B. As a result, the height dimension from the front bottom plate 13 to the foot portion of the lower boom 5A can be reduced, and the torsional moment and bending moment applied to the left and right front vertical plates 14 and 17 from the lower boom 5A can be suppressed accordingly. .

  Therefore, it is necessary to provide a reinforcing member between the left and right front vertical plates and the front bottom plate as in the prior art, or to configure the front side of the left and right vertical plates (center beam) in a box shape. The center frame 12 can be made small and light. In addition, since the height position of the foot portion of the lower boom 5A can be lowered, the height of the excavator 1 as a whole can also be lowered. Therefore, for example, even when a trailer loaded with the hydraulic excavator 1 travels on a public road, this height dimension can be easily kept within a range regulated by laws and the like.

  According to the present embodiment, the left and right cylinder pin insertion holes 16A, 21A corresponding to the reduced height dimension A from the front bottom plate 13 to the hole center of the boom pin insertion holes 15A, 18A. , 19A, 22A and the distance D in the horizontal direction between the boom pin insertion holes 15A, 18A. Therefore, in this embodiment, a large separation dimension C between the hole centers of the cylinder pin insertion holes 16A, 21A, 19A, and 22A and the boom pin insertion holes 15A and 18A can be secured. Thereby, even when the height dimension A from the front bottom plate 13 to the hole center of the boom pin insertion holes 15A, 18A is lowered, the separation dimension between the foot part of the lower boom 5A and the base end part of each boom cylinder 5E. C can be secured large, and the force of each boom cylinder 5E can be used effectively.

  According to the present embodiment, the distance E between the center line SS in the rear direction and the turning center O of the center frame 12 is set small before passing through the middle between the left front vertical plate 14 and the right front vertical plate 17. Accordingly, in the present embodiment, the engagement (positional relationship) between the left front vertical plate 14 and the right front vertical plate 17 with respect to the turning wheel 3 can be made closer to each other in the left and right directions. As a result, the swivel wheel 3 can receive the force applied from the front vertical plates 14 and 17 via the front bottom plate 13 in the left and right directions in a more nearly equal state, and the twist of the center frame 12 can be reduced. Can do. That is, the center frame 12 can be advantageously configured in terms of strength.

  In other words, as in the present embodiment, the horizontal distance D between the hole centers of the cylinder pin insertion holes 16A, 21A, 19A, 22A and the boom pin insertion holes 15A, 18A is set large. Then, the protruding amount (overhang amount) to the front side of the base end portion of each boom cylinder 5E increases. However, in the present embodiment, by setting the distance E to be small, the deviation amount (offset amount) of each boom cylinder 5E with respect to the turning center O can be reduced so that the strength of the center frame 12 as a whole can be ensured. Yes.

  Furthermore, according to this Embodiment, it is set as the structure which bends the front board 20 which connects the front part side between the left and right front vertical boards 14 and 17 in two places. As a result, in the present embodiment, the strength of the front plate 20 can be improved as compared with the front plate 20 ′ formed by bending at one place as in the comparative example shown in FIGS. 10 and 11.

  In the present embodiment, the hydraulic excavator 1 including the working device 5 having the two-piece boom specification in which the boom is divided into the lower boom 5A and the upper boom 5B has been described as an example. However, the present invention is not limited to this. For example, the present invention can be applied to a hydraulic excavator including a mono-boom specification working device constituted by a single boom.

  Further, in the present embodiment, the wheel-type hydraulic excavator 1 having the wheels 2B as the construction machine has been described as an example. However, the present invention is not limited to this, and other examples such as a crawler-type hydraulic excavator are available. It may be applied to construction machinery.

1 Excavator (construction machine)
2 Lower traveling body 4 Upper revolving body 5 Working device 5A Lower boom (boom)
5E Boom cylinder 11 Swivel frame 12, 12 'Center frame 13, 13' Front bottom plate 14, 14 'Left front vertical plate 14A Left bracket part 15A, 15A' Left boom pin insertion hole 16A, 21A, 16A 'Left cylinder pin insertion Hole 17, 17 'Right front vertical plate 17A Right bracket portion 18A, 18A' Right boom pin insertion hole 19A, 22A, 19A 'Right cylinder pin insertion hole 20, 20' Front plate 20B First bent portion 20D Second Bending portions 30, 30 'tail frames 31, 32, 31', 32 'left and right I-shaped beams 31A, 32A left, right rear vertical plates 31B, 32B, 31B', 32B 'upper flange portion 31C, 32C Lower flange part 33 Rear bottom plate A, Ap Height dimension B, Bp Height dimension C, Cp Separation dimension D, Dp Horizontal distance E, Ep distance O, Op turning center S-S, Sp-Sp center line

Claims (5)

A lower traveling body (2), an upper revolving body (4) that is turnably mounted on the lower traveling body (2), and a front side of the upper revolving body (4) that can be raised and lowered. A working device (5),
The center frame (12) of the revolving frame (11) constituting the upper revolving structure (4) extends in the front and rear directions on the front bottom plate (13) and the front bottom plate (13), and in the left and right directions. The left and right front vertical plates (14, 17) and
A tail frame (30) connected to the rear side of the center frame (12), and left and right I-shaped beams (31, 32) joined to the rear part of the front vertical plates (14, 17); A rear bottom plate (33) connecting the I-shaped beams (31, 32),
The left and right I-shaped beams (31, 32) extend in the front and rear directions, and the left and right rear vertical plates (31A, 32A) whose front ends are joined to the front vertical plates (14, 17). The upper flange portion (31B, 32B) provided on the upper side of each rear vertical plate (31A, 32A) and extending in the front and rear directions and having a front end joined to each front vertical plate, and each rear vertical plate (31A) , 32A), the construction machine is formed by lower flange portions (31C, 32C) which are provided on the lower side and extend in the front and rear directions and whose front ends are joined to the front bottom plate (13).
The bracket portions (14A, 17A) of the center frame (12) are provided with boom pin insertion holes (15A, 18A) for pin-joining the foot portions of the boom (5A),
A height dimension from the front bottom plate (13) to the hole center of the boom pin insertion hole (15A, 18A) is (A), and the front end of the upper flange portion (31B, 32B) from the front bottom plate (13). A construction machine characterized in that the height dimension (A) is set smaller than the height dimension (B) when the height dimension up to (B) is taken. The boom cylinder (5E) is pin-coupled to the bracket portion (14A, 17A) of the center frame (12) at a position in front of and below the boom pin insertion hole (15A, 18A). Providing cylinder pin insertion holes (16A, 19A)
The hole center of the cylinder pin insertion hole (16A, 19A) and the hole pin insertion hole (15A, 18A) when the height dimension (A) is set smaller than the height dimension (B). And the distance in the horizontal direction is (D).
For comparison, the height dimension (Ap) from the front bottom plate (13 ′) to the center of the hole of the boom pin insertion hole (15A ′, 18A ′) is determined from the front bottom plate (13 ′) to the upper flange portion (31B ′, 32B ′). ) Between the hole center of the cylinder pin insertion hole (16A ', 19A') and the hole pin insertion hole (15A ', 18A') when the height dimension (Bp) to the front end is larger. When the separation dimension is (Cp) and the horizontal distance is (Dp),
The distance (D) corresponding to the height dimension (A) lower than the height dimension (Ap) so that the separation dimension (C) is substantially the same as the separation dimension (Cp). ) Is set to be larger than the distance (Dp). When the height dimension (A) is set to be smaller than the height dimension (B), the center frame (12) has a front and rear direction that passes through the middle of the left front vertical plate (14) and the right front vertical plate (17). The distance between the center line (SS) and the turning center (O) of the center frame (12) is (E),
As a comparison object, the height dimension (Ap) from the front bottom plate (13 ′) to the center of the hole of the boom pin insertion hole (15A ′, 18A ′) is changed from the front bottom plate (13 ′) to the upper flange portion (31B ′, 32B). The center of the center frame (12 ′) before and after passing through the middle of the left front vertical plate (14 ′) and the right front vertical plate (17 ′) when the height dimension (Bp) to the front end of ′) is larger. When the distance between the line (Sp−Sp) and the turning center (Op) of the center frame (12 ′) is (Ep),
The construction machine according to claim 1, wherein the distance (E) is set smaller than the distance (Ep). The boom cylinder (5E) is pin-coupled to the bracket portion (14A, 17A) of the center frame (12) at a position in front of and below the boom pin insertion hole (15A, 18A). Providing cylinder pin insertion holes (16A, 19A)
The hole center of the cylinder pin insertion hole (16A, 19A) and the hole pin insertion hole (15A, 18A) when the height dimension (A) is set smaller than the height dimension (B). (C), the horizontal distance is (D), and the center frame (12) passes through the middle of the left front vertical plate (14) and the right front vertical plate (17) before and after. The distance between the center line (SS) and the center of rotation (O) of the center frame (12) is (E),
For comparison, the height dimension (Ap) from the front bottom plate (13 ′) to the center of the hole of the boom pin insertion hole (15A ′, 18A ′) is determined from the front bottom plate (13 ′) to the upper flange portion (31B ′, 32B ′). ) Between the hole center of the cylinder pin insertion hole (16A ', 19A') and the hole pin insertion hole (15A ', 18A') when the height dimension (Bp) to the front end is larger. The separation dimension is (Cp), the horizontal distance is (Dp), and the center frame (12 ') passes through the middle of the left front vertical plate (14') and right front vertical plate (17 ') before and after. When the distance between the center line (Sp−Sp) of the center and the turning center (Op) of the center frame (12 ′) is (Ep),
The distance (D) corresponding to the height dimension (A) lower than the height dimension (Ap) so that the separation dimension (C) is substantially the same as the separation dimension (Cp). ) Is set larger than the distance (Dp), and the distance (E) is set smaller than the distance (Ep). On the front side between the left and right front vertical plates (14, 17), a front plate (20) extends in the left and right directions and connects the left and right front vertical plates (14, 17). Provided,
The front plate (20) is configured to be provided with a first bent portion (20B) and a second bent portion (20D) bent at two locations in the front and rear directions. Construction machinery.

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