Work machine

Abstract

A frame coupling mechanism (16) for coupling a left side frame (11) to a left front attachment leg (7) is configured to comprise: a guide member (17) that is attached to the left side frame (11) and forms a space (19) between said guide member (17) and a flange part (7A) of the left front attachment leg (7); a wedge member (20) that is provided between the flange part (7A) and the guide member (17) and that comes into contact with the flange part (7A) by moving within the space (19) along the guide member (17); and a block body (21) that is provided to the guide member (17) and that restricts the movement of the wedge member (20) at a position where the wedge member (20) comes in contact with the flange part (7A) and the guide member (17).

Description

Work machinery

[0001] The present disclosure relates to a work machine such as a hydraulic excavator, and more particularly to a work machine in which the distance between left and right side frames that constitute a lower traveling body is variable.

[0002] A hydraulic excavator, a typical example of a construction machine, has a vehicle body made up of a self-propelled lower chassis and an upper rotating chassis rotatably mounted on the lower chassis, with a work device for performing excavation work and the like mounted on the front side of the upper rotating chassis. The lower chassis of a hydraulic excavator includes a center frame to which the upper rotating chassis is attached and side frames disposed on both the left and right sides of the center frame. The center frame is provided with mounting legs that extend out in the left and right directions, and the side frames are attached to the mounting legs.

[0003] Some hydraulic excavators have a variable width undercarriage (the distance between the left and right side frames) that can be adjusted by changing the mounting positions of the side frames relative to the center frame. When this type of hydraulic excavator is loaded onto a transport vehicle and transported to a work site, the width of the undercarriage can be reduced to fit within the transport width limit, and when excavation work or the like is performed, the width of the undercarriage can be expanded to increase the stability of the vehicle body.

[0004] In a structure in which the mounting legs of the center frame and the side frames are fastened together using multiple bolts, the multiple bolts are typically inserted into the bolt insertion holes of the mounting legs and screwed into the bolt holes of the side frames. Therefore, by arranging the multiple bolt insertion holes and bolt holes at equal intervals in the left-right direction (width direction), the mounting position of the side frames relative to the mounting legs can be moved left-right within the range of the bolt holes and bolt insertion holes, making it possible to adjust the width of the undercarriage. However, this structure requires the complicated task of attaching and detaching multiple bolts when changing the width of the undercarriage, which reduces workability.

[0005] In response to this problem, a structure is known in which the side frames are attached to the center frame by inserting the mounting legs of the center frame into fitting holes provided in the side frames. With this structure, the width dimension of the undercarriage can be adjusted by changing the insertion depth of the mounting legs into the fitting holes without attaching or removing bolts (Patent Document 1).

[0006] Japanese Patent Application Laid-Open No. 2018-017047

[0007] However, in the prior art of Patent Document 1, a gap is required between the fitting holes provided in the side frames and the mounting legs in order to insert and remove the mounting legs from the fitting holes, which results in a gap at the connection between the mounting legs of the center frame and the side frames.As a result, when performing excavation work or the like using a work implement with the width dimension of the undercarriage expanded, the gap formed at the connection between the mounting legs of the center frame and the side frames causes the vehicle body to shake (rattle), which causes a problem of reduced workability in excavation work.

[0008] The present invention has been made in consideration of the problems of the prior art described above, and an object of the present invention is to provide a work machine that can reduce gaps that occur at the connection between the mounting legs of the center frame and the side frames.

[0009] The present invention is a working machine comprising a self-propelled lower running body and an upper rotating body rotatably mounted on the lower running body, the lower running body comprising a center frame having a frame main body to which the upper rotating body is attached and mounting legs that extend laterally from the frame main body and have flange portions at their tips, side frames that are arranged on both the left and right sides of the center frame and are attached to the flange portions, and a frame connecting mechanism that connects the side frames to the mounting legs, wherein the frame connecting mechanism is characterized in that it comprises: guide members that are attached to the side frames and form a space between them and the flange portions; wedge members that are provided between the flange portions and the guide member and move along the guide member within the space to abut against the flange portions and the guide member; and a stopper member that is provided on the guide member and restricts movement of the wedge member at a position where the wedge member abuts against the flange portions and the guide member.

[0010] According to the present invention, a wedge member is inserted into the space formed between the flange portion of the mounting leg and the guide member, and this wedge member abuts against the flange portion and the guide member, thereby allowing the side frame to be connected to the flange portion of the mounting leg without any gaps.

[0011] 4 is a left side view of a hydraulic excavator according to an embodiment of the present invention. It is a plan view showing the lower running body with the crawler removed and the spacing between the side frames expanded. It is a plan view showing the lower running body with the crawler removed and the spacing between the side frames reduced. It is an enlarged plan view of a main portion, showing the frame connection mechanism and the like according to the first embodiment, arranged at section IV in FIG. 2. It is a left side view of the left front mounting leg, left side frame, and frame connection mechanism, as viewed from the direction of arrows V-V in FIG. 4. It is an exploded perspective view showing the left front mounting leg, left side frame, and frame connection mechanism. It is an exploded perspective view showing the guide member, wedge member, and stopper member of the frame connection mechanism. It is a cross-sectional view of the flange portion of the left front mounting leg, the left side frame, the frame connection mechanism, and the like, as viewed from the direction of arrows VIII-VIII in FIG. 4. It is a cross-sectional view taken from the same position as FIG. 8, showing the wedge member detached from the flange portion. It is a cross-sectional view of the flange portion, guide member, wedge member, stopper member, shim, and the like, as viewed from the direction of arrows X-X in FIG. 8. 17 is a cross-sectional view of the flange portion, guide member, wedge member, etc., as viewed in the direction of arrows XI-XI in FIG. 8. This is an enlarged plan view of essential parts of the frame connection mechanism according to the second embodiment, together with the left front mounting leg. This is a left side view of the left front mounting leg, left side frame, and frame connection mechanism, as viewed in the direction of arrows XIII-XIII in FIG. 12. This is a cross-sectional view of the flange portion of the left front mounting leg, the left side frame, and the frame connection mechanism, as viewed in the direction of arrows XIV-XIV in FIG. 12. This is a cross-sectional view taken from the same position as FIG. 14, showing the wedge member detached from the flange portion. This is a cross-sectional view of the flange portion, guide member, wedge member, stopper member, biasing member, etc., as viewed in the direction of arrows XVI-XVI in FIG. 14. This is an enlarged plan view of essential parts of the frame connection mechanism according to the third embodiment, together with the left front mounting leg. This is a left side view of the left front mounting leg, left side frame, and frame connection mechanism, as viewed in the direction of arrows XVIII-XVIII in FIG. This is a cross-sectional view of the flange portion of the left front mounting leg, the left side frame, and the frame connecting mechanism as viewed from the direction of arrows XIX-XIX in Figure 17. This is a cross-sectional view of the flange portion, guide member, wedge member, wedge pressing member, wedge returning member, etc. as viewed from the direction of arrows XX-XX in Figure 19. This is a cross-sectional view taken from the same position as Figure 19, showing the wedge member detached from the flange portion.22 is a cross-sectional view of the flange portion, the guide member, the wedge member, the wedge pressing member, the wedge returning member, etc., taken along the arrows XXII-XXII in FIG. 21.

[0012] Hereinafter, a hydraulic excavator will be described as an example of a work machine according to an embodiment of the present invention with reference to the accompanying drawings. In the embodiment, the traveling direction of the hydraulic excavator will be described as the front-rear direction, and the direction perpendicular to the traveling direction will be described as the left-right direction.

[0013] 1 to 11 show a first embodiment of the present invention. In Fig. 1, a hydraulic excavator 1 is configured to include a self-propelled crawler-type undercarriage 2, an upper rotating body 4 rotatably mounted on the undercarriage 2 via a slewing ring 3, and a working device 5 rotatably provided on the front side of the upper rotating body 4. The hydraulic excavator 1 is self-propelled to a work site by the undercarriage 2, and performs work such as excavating earth and sand using the working device 5 while rotating the upper rotating body 4.

[0014] The lower traveling body 2 is composed of a center frame 6 to which the upper rotating body 4 is attached, a left front mounting leg 7, a left rear mounting leg 8, a right front mounting leg 9, and a right rear mounting leg 10 that extend out in the left and right directions from the center frame 6, and a left side frame 11 and a right side frame 12 that are arranged on either side of the center frame 6. The left side frame 11 is attached to the left front mounting leg 7 and the left rear mounting leg 8, and the right side frame 12 is attached to the right front mounting leg 9 and the right rear mounting leg 10.

[0015] A drive wheel 13 is disposed at one end of each of the left and right side frames 11 and 12 in the longitudinal direction, and the drive wheel 13 is rotationally driven by a traveling device 13A. An idler wheel 14 is rotatably attached to the other end of each of the left and right side frames 11 and 12 in the longitudinal direction. An endless crawler belt 15 is wound around each of the drive wheel 13 and the idler wheel 14 provided on the left and right side frames 11 and 12. The crawler belt 15 moves in an orbit when the drive wheel 13 is rotated by the traveling device 13A, allowing the undercarriage 2 to travel stably on uneven terrain, etc.

[0016] The width dimension of the undercarriage 2 can be changed between an expanded dimension A shown in Fig. 2 and a contracted dimension B shown in Fig. 3. When the hydraulic excavator 1 performs excavation work or the like at a work site, the stability of the vehicle body during work can be improved by setting the width dimension of the undercarriage 2 to the expanded dimension A. On the other hand, when the hydraulic excavator 1 is loaded onto a transport vehicle and transported to the work site, for example, the width dimension of the undercarriage 2 can be set to the contracted dimension B, so that it fits within the transport width limit.

[0017] As shown in Figures 2 and 3, the center frame 6 forms the center of the undercarriage 2. The center frame 6 is formed, for example, by welding multiple steel plates together to form a sturdy, H-shaped structure in a plan view. The center frame 6 includes a frame main body 6B and multiple (e.g., four) mounting legs. A cylindrical body 6A for mounting the slewing ring 3 is fixed to the upper surface of the frame main body 6B. The base ends of the multiple mounting legs are integrally fixed to the frame main body 6B, and their tip ends extend laterally from the frame main body 6B. These multiple mounting legs include a left front mounting leg 7 and a left rear mounting leg 8 located on the left front and left rear sides of the center frame 6, and a right front mounting leg 9 and a right rear mounting leg 10 located on the right front and right rear sides of the center frame 6.

[0018] A flange portion 7A for mounting the left side frame 11 is integrally formed on the tip of the left front mounting leg 7. The flange portion 7A is formed like a plate that protrudes in the front-to-rear direction from the tip of the left front mounting leg 7. A lower surface 7B of the flange portion 7A is flat and abuts against an upper surface 11A, which is the surface of the left side frame 11. As shown in FIG. 5 , flange-side inclined surfaces 7C are integrally formed on both front-to-rear sides of the flange portion 7A. The flange-side inclined surfaces 7C are inclined obliquely upward from the lower surface 7B with respect to the upper surface 11A of the left side frame 11. Similarly, a flange portion 8A is integrally formed on the tip of the left rear mounting leg 8. A lower surface (not shown) of the flange portion 8A is flat, and flange-side inclined surfaces 8B are integrally formed on both front-to-rear sides of the flange portion 8A.

[0019] Meanwhile, a flange portion 9A for attaching the right side frame 12 is integrally formed on the tip side of the right front mounting leg 9. The lower surface (not shown) of the flange portion 9A is flat and abuts against the upper surface 12A, which is the surface of the right side frame 12. In addition, flange-side inclined surfaces 9B are integrally formed on both front-rear sides of the flange portion 9A. The flange-side inclined surfaces 9B are inclined obliquely upward from the lower surface with respect to the upper surface 12A of the right side frame 12. Similarly, a flange portion 10A is integrally formed on the tip side of the right rear mounting leg 10. The lower surface (not shown) of the flange portion 10A is flat and flange-side inclined surfaces 10B are integrally formed on both front-rear sides of the flange portion 10A.

[0020] A left side frame 11 is attached to the flange portion 7A of the left front mounting leg 7 and the flange portion 8A of the left rear mounting leg 8 using a frame connecting mechanism 16. A right side frame 12 is attached to the flange portion 9A of the right front mounting leg 9 and the flange portion 10A of the right rear mounting leg 10 using the frame connecting mechanism 16. The mounting position of the left side frame 11 relative to the left front mounting leg 7 and the left rear mounting leg 8, and the mounting position of the right side frame 12 relative to the right front mounting leg 9 and the right rear mounting leg 10, can be changed using the frame connecting mechanism 16. This changes the distance between the left side frame 11 and the right side frame 12, allowing the width dimension of the lower running body 2 to be changed between dimension A when expanded and dimension B when contracted.

[0021] Next, the frame connecting mechanism 16 according to this embodiment will be described.

[0022] As shown in Figures 2 and 3, a plurality of (e.g., three) frame connecting mechanisms 16 are provided between the flange portion 7A of the left front mounting leg 7 and the left side frame 11, between the flange portion 8A of the left rear mounting leg 8 and the left side frame 11, between the flange portion 9A of the right front mounting leg 9 and the right side frame 12, and between the flange portion 10A of the right rear mounting leg 10 and the right side frame 12.

[0023] 4 and 6, multiple (three) frame connection mechanisms 16 are provided between the flange portion 7A of the left front mounting leg 7 and the left side frame 11. That is, one frame connection mechanism 16 is disposed at the rear of the flange portion 7A, and two frame connection mechanisms 16 are disposed at the front of the flange portion 7A, aligned in the left-right direction and integrated together. Because these three frame connection mechanisms 16 have the same configuration, the following description will focus on the frame connection mechanism 16 disposed at the rear of the flange portion 7A of the left front mounting leg 7.

[0024] As shown in FIGS. 6 to 11, the frame connection mechanism 16 according to this embodiment includes a guide member 17, a wedge member 20, a block body 21, and a shim 22.

[0025] The guide member 17 is fixed to the upper surface 11A of the left side frame 11 adjacent to the rear side of the flange portion 7A provided on the left front mounting leg 7, and movably supports a wedge member 20 (described below). The guide member 17 is formed in a block shape having an upper surface 17A, a lower surface 17B, a front surface 17C, a rear surface 17D, and left and right side surfaces 17E. A wedge fitting hole 17F is formed in the left-right middle portion of the guide member 17, penetrating in the front-rear direction from the front surface 17C to the rear surface 17D. The wedge fitting hole 17F is a circular hole with a circular cross section, into which the wedge member 20 is slidably inserted. The guide member 17 is formed with multiple (four) bolt insertion holes 17G penetrating in the vertical direction from the upper surface 17A to the lower surface 17B on both left and right sides of the wedge fitting hole 17F. The guide member 17 is fixed to the upper surface 11A of the left side frame 11 by screwing a bolt 18 inserted into the bolt insertion hole 17G into the left side frame 11.

[0026] The front side of the guide member 17 is formed with a notch 17H, which is cut out by carving out the bottom surface 17B and the left and right side surfaces 17E from the front surface 17C to the rear surface 17D. As shown in Figure 9, when the guide member 17 is fixed to the left side frame 11 with bolts 18, the notch 17H of the guide member 17 is positioned above the flange-side inclined surface 7C of the flange portion 7A. As a result, a space 19 is formed between the front end of the guide member 17 and the flange-side inclined surface 7C of the flange portion 7A, extending in the length direction (front-rear direction) of the left side frame 11 and continuing from the wedge fitting hole 17F.

[0027] A rectangular hole 17J extending vertically from the upper surface 17A to the lower surface 17B is formed on the rear side of the guide member 17. The rectangular hole 17J is formed as a bottomed hole having a width dimension equivalent to the diameter of the wedge fitting hole 17F, for example, and communicates with the wedge fitting hole 17F. A block body 21 and a shim 22 (described later) are housed in the rectangular hole 17J so as to be detachable in the vertical direction.

[0028] The wedge member 20 is provided in the wedge fitting hole 17F of the guide member 17. The wedge member 20 is formed in a cylindrical shape with a circular cross section and a diameter equal to the diameter of the wedge fitting hole 17F. The wedge member 20 is slidably inserted into the wedge fitting hole 17F and movable in the length direction (front-rear direction) of the left side frame 11 and the left front mounting leg 7 relative to the left side frame 11. A wedge-side inclined surface 20B inclined with respect to the upper surface 11A of the left side frame 11 is formed on one end 20A of the wedge member 20 in the movement direction (front-rear direction). The wedge-side inclined surface 20B has the same inclination angle as the flange-side inclined surface 7C formed on the flange portion 7A and faces the flange-side inclined surface 7C in the movement direction of the wedge member 20. This allows the wedge-side inclined surface 20B to come into surface contact with the flange-side inclined surface 7C of the flange portion 7A. The wedge member 20 is movable between a position where the wedge side inclined surface 20B abuts against the flange side inclined surface 7C of the flange portion 7A (position in Figure 8) and a position where the wedge side inclined surface 20B is separated from the flange side inclined surface 7C of the flange portion 7A (position in Figure 9).

[0029] With the wedge member 20 inserted into the wedge fitting hole 17F of the guide member 17, one end 20A of the wedge member 20 is positioned in the space 19 formed between the guide member 17 and the flange-side inclined surface 7C of the flange portion 7A. In this state, the one end 20A of the wedge member 20 moves forward (toward the flange portion 7A) within the space 19 along the wedge fitting hole 17F of the guide member 17. Then, as shown in FIG. 8 , by inserting the one end 20A of the wedge member 20 between the flange portion 7A and the guide member 17, the wedge member 20 abuts against both the guide member 17 (the inner peripheral surface of the wedge fitting hole 17F) and the flange portion 7A (the flange-side inclined surface 7C) without any gaps. As a result, the flange portion 7A of the left front mounting leg 7 and the left side frame 11 are connected via the wedge member 20 without any gaps.

[0030] Here, the wedge-side inclined surface 20B has the same inclination angle as the flange-side inclined surface 7C formed on the flange portion 7A and faces the flange-side inclined surface 7C in the movement direction of the wedge member 20. Therefore, by moving the wedge member 20 toward the flange portion 7A, the wedge-side inclined surface 20B can be reliably brought into contact with the flange-side inclined surface 7C. When the wedge member 20 is moved, the amount of change in the gap between the wedge-side inclined surface 20B and the flange-side inclined surface 7C is smaller than the amount of movement of the wedge member 20. Therefore, by appropriately setting the inclination angles of the wedge-side inclined surface 20B and the flange-side inclined surface 7C, the gap between the wedge-side inclined surface 20B and the flange-side inclined surface 7C can be finely adjusted. Moreover, the wedge member 20 has a circular cross-sectional shape, and the wedge fitting hole 17F of the guide member 17 is formed as a circular hole into which the wedge member 20 is slidably inserted. As a result, when the wedge member 20 abuts against the flange portion 7A, even if the wedge-side inclined surface 20B is not directly facing the flange-side inclined surface 7C, the wedge member 20 can rotate within the wedge fitting hole 17F. This allows the wedge-side inclined surface 20B to follow the flange-side inclined surface 7C of the flange portion 7A and make surface contact with it, allowing it to abut against the flange-side inclined surface 7C without any gaps.

[0031] A block body 21 serving as a stopper member is provided within the rectangular hole 17J of the guide member 17. The block body 21 restricts movement of the wedge member 20 when the wedge member 20 abuts against the flange portion 7A of the left front mounting leg 7 and the guide member 17. The block body 21 is formed, for example, in the shape of a rectangular parallelepiped block, and is detachably attached in the rectangular hole 17J of the guide member 17 in the vertical direction. As shown in FIG. 8 , the block body 21 is placed within the rectangular hole 17J with the wedge member 20 abutting against the flange portion 7A and the guide member 17, and restricts movement of the wedge member 20 by abutting against the other end 20C in the movement direction. This holds the wedge member 20 in a position where it abuts against the flange portion 7A of the left front mounting leg 7 and the guide member 17. A U-shaped handle 21A is fixed to the top surface of the block body 21 by welding or other means, and by gripping the handle 21A, the block body 21 can be easily attached to and detached from the rectangular hole 17J of the guide member 17.

[0032] The shim 22 is provided in the rectangular hole 17J of the guide member 17 together with the block body 21, and is disposed between the other end 20C of the wedge member 20 and the block body 21. The shim 22 has, for example, the same rectangular shape as the block body 21 and is formed from multiple thin plates of different thicknesses. The shims 22 are detachably attached in the vertical direction within the rectangular hole 17J of the guide member 17, and the position of the wedge member 20 relative to the flange portion 7A is finely adjusted depending on the number of shims 22. This allows the wedge member 20 to abut against both the guide member 17 and the flange portion 7A without any gaps.

[0033] The shim 22 is used to finely adjust the position of the wedge member 20 relative to the flange portion 7A and is not an essential component. That is, if the wedge member 20 abuts against both the guide member 17 and the flange portion 7A without any gaps when the block body 21 is placed in the square hole 17J of the guide member 17, the shim 22 can be omitted. Furthermore, the shim 22 may be placed not only between the other end 20C of the wedge member 20 and the block body 21 but also, for example, between the guide member 17 and the block body 21.

[0034] The frame connecting mechanism 16 that connects the left front mounting leg 7 of the center frame 6 to the left side frame 11 has the configuration described above. Similarly, the frame connecting mechanism 16 that connects the left rear mounting leg 8 to the left side frame 11, the frame connecting mechanism 16 that connects the right front mounting leg 9 to the right side frame 12, and the frame connecting mechanism 16 that connects the right rear mounting leg 10 to the right side frame 12 each include a guide member 17, a wedge member 20, a block body 21, and a shim 22.

[0035] Next, we will explain the process of releasing the connection between the left side frame 11 and the left front mounting leg 7 by the frame connection mechanism 16 in order to change the width dimension of the lower running body 2 from dimension B when contracted to dimension A when expanded.

[0036] When the frame connecting mechanism 16 connects the flange portion 7A of the left front mounting leg 7 and the left side frame 11, the wedge member 20 abuts against both the guide member 17 (the inner peripheral surface of the wedge fitting hole 17F) and the flange portion 7A (the flange-side inclined surface 7C) without any gaps, as shown in Figure 8. A block body 21 and a shim 22 arranged in the square hole 17J of the guide member 17 abut against the other end portion 20C of the wedge member 20, thereby restricting movement of the wedge member 20.

[0037] To release this connected state, for example, as shown in Figure 9, the handle 21A of the block body 21 placed in the square hole 17J of the guide member 17 is grasped and the block body 21 is pulled out above the guide member 17. The shim 22, which is placed in the square hole 17J together with the block body 21, is also pulled out above the guide member 17. This releases the restriction on the movement of the wedge member 20, allowing the wedge member 20 to move within the wedge fitting hole 17F of the guide member 17. As a result, a gap 23 is formed between the wedge-side inclined surface 20B of the wedge member 20 and the flange-side inclined surface 7C of the flange portion 7A in the space 19 formed between the flange portion 7A and the notch 17H of the guide member 17.

[0038] In this way, simply by removing the block body 21 from the guide member 17, a gap 23 is formed between the wedge-side inclined surface 20B of the wedge member 20 and the flange-side inclined surface 7C of the flange portion 7A, easily releasing the connection between the left front mounting leg 7 and the left side frame 11. Similarly, by releasing the connection between the left rear mounting leg 8 and the left side frame 11, the left side frame 11 becomes movable in the left-right direction. Meanwhile, by releasing the connection between the right front mounting leg 9 and the right rear mounting leg 10 and the right side frame 12, the right side frame 12 becomes movable in the left-right direction. In this state, for example, span cylinders (not shown) provided between the center frame 6 and the left side frame 11 and between the center frame 6 and the right side frame 12 are extended. This allows the width dimension of the undercarriage 2 to be changed from a retracted dimension B, which is suitable for loading the hydraulic excavator 1 onto a transport vehicle, to an extended dimension A, which is suitable for performing excavation work using the hydraulic excavator 1.

[0039] After changing the width dimension of the lower running body 2 to the expanded dimension A, the left side frame 11 is connected to the flange portion 7A of the left front mounting leg 7 using the frame connection mechanism 16. Specifically, for example, a rod-shaped jig (not shown) is inserted into the wedge fitting hole 17F from the rear surface 17D side of the guide member 17, and the other end portion 20C of the wedge member 20 is pressed toward the flange portion 7A. This eliminates the gap 23 formed between the wedge-side inclined surface 20B of the wedge member 20 and the flange-side inclined surface 7C of the flange portion 7A, and the wedge-side inclined surface 20B abuts against the flange-side inclined surface 7C.

[0040] In this state, the block body 21 is inserted into the square hole 17J of the guide member 17, and the block body 21 abuts against the other end 20C of the wedge member 20 to restrict movement of the wedge member 20. This holds the wedge member 20 in a position where it abuts against the flange portion 7A of the left front mounting leg 7 and the guide member 17. If there is a gap between the other end 20C of the wedge member 20 and the block body 21 at this time, a shim 22 is inserted between them to fine-tune the position of the wedge member 20 relative to the flange portion 7A. As a result, as shown in FIG. 8 , the wedge member 20 can be inserted between the guide member 17 (the inner peripheral surface of the wedge fitting hole 17F) and the flange portion 7A (the flange-side inclined surface 7C) and abutted against them without any gaps, and the left front mounting leg 7 and the left side frame 11 can be connected together using the wedge member 20 without any gaps.

[0041] Similarly, the left rear mounting leg 8 and the left side frame 11, and the right front mounting leg 9 and right rear mounting leg 10 and the right side frame 12 can be connected without gaps using the frame connecting mechanism 16. In this way, with the width dimension of the lower running body 2 changed to the expanded dimension A, the left front mounting leg 7 and the left rear mounting leg 8 and the left side frame 11, and the right front mounting leg 9 and right rear mounting leg 10 and the right side frame 12 can be connected without gaps using the frame connecting mechanism 16. As a result, rattle due to gaps at the connection between the left front mounting leg 7 and the left side frame 11 is suppressed, and shaking that occurs when the hydraulic excavator 1 is performing excavation work using the work implement 5 is prevented, thereby improving the workability of the excavation work.

[0042] Furthermore, the frame connecting mechanism 16 has a guide member 17 attached to the left side frame 11 and a wedge member 20 that moves along the guide member 17, and can connect the left front mounting leg 7 to the left side frame 11 by inserting the wedge member 20 between the guide member 17 and the flange portion 7A and bringing them into contact with each other. Therefore, compared to a configuration in which, for example, multiple bolts are used to connect the flange portion of the left front mounting leg 7 to the left side frame 11, workability can be improved when connecting and releasing the flange portion 7A of the left front mounting leg 7 to the left side frame 11.

[0043] Furthermore, because the wedge member 20 of the frame connecting mechanism 16 moves in the length direction (front-rear direction) of the left side frame 11, the guide member 17 that movably supports the wedge member 20 does not protrude in the left-right direction from the left side frame 11. This allows the frame connecting mechanism 16 to be arranged compactly between the upper surface 11A of the left side frame 11 and the crawler track 15, contributing to space savings.

[0044] Thus, in this embodiment, the frame connecting mechanism 16 that connects the left side frame 11 to the left front mounting leg 7 is attached to the left side frame 11 and includes a guide member 17 that forms a space 19 between it and the flange portion 7A of the left front mounting leg 7, a wedge member 20 that is provided between the flange portion 7A and the guide member 17 and moves along the guide member 17 within the space 19 to come into contact with the flange portion 7A, and a block body 21 that is provided on the guide member 17 and restricts the movement of the wedge member 20 at the position where the wedge member 20 comes into contact with the flange portion 7A and the guide member 17.

[0045] With this configuration, by inserting the wedge member 20 between the guide member 17 and the flange portion 7A and abutting them, it is possible to connect the left front mounting leg 7 and the left side frame 11 without any gaps. As a result, it is possible to prevent rattling due to gaps at the connection between the left front mounting leg 7 and the left side frame 11, preventing shaking that occurs when the hydraulic excavator 1 is performing excavation work using the work implement 5, and improving the workability of the excavation work.

[0046] In this embodiment, the flange portion 7A is provided with a flange-side inclined surface 7C that is inclined relative to the upper surface 11A of the left side frame 11, and the wedge member 20 is provided with a wedge-side inclined surface 20B that faces the flange-side inclined surface 7C in the movement direction of the wedge member 20 and is capable of surface contact with the flange-side inclined surface 7C. With this configuration, by moving the wedge member 20 toward the flange portion 7A, the wedge-side inclined surface 20B can be reliably brought into contact with the flange-side inclined surface 7C. Furthermore, the surface contact of the wedge-side inclined surface 20B with the flange-side inclined surface 7C can increase the connection strength between the left front mounting leg 7 and the left side frame 11, which are connected using the frame connection mechanism 16.

[0047] In this embodiment, the wedge member 20 is formed in a cylindrical shape with a circular cross section, and the guide member 17 is formed with a wedge fitting hole 17F (circular hole) into which the wedge member 20 is slidably inserted. With this configuration, when the wedge member 20 abuts against the flange portion 7A, the wedge member 20 can rotate within the wedge fitting hole 17F even if the wedge-side inclined surface 20B does not directly face the flange-side inclined surface 7C. This allows the wedge-side inclined surface 20B to reliably follow and come into surface contact with the flange-side inclined surface 7C of the flange portion 7A.

[0048] In this embodiment, one end 20A of the wedge member 20 in the movement direction, which is the wedge-side inclined surface 20B in this embodiment, abuts against the flange portion 7A, which is the flange-side inclined surface 7C in this embodiment. The stopper member is detachably provided between the other end 20C of the wedge member 20 in the movement direction and the guide member 17, and is composed of a block body 21 that abuts against the other end 20C of the wedge member 20 when the one end 20A of the wedge member 20 abuts against the flange portion 7A of the left front mounting leg 7. With this configuration, simply by disposing the block body 21 between the other end 20C of the wedge member 20 and the guide member 17, it is possible to restrict the movement of the wedge member 20 at the position where it abuts against the flange portion 7A and the guide member 17, and the configuration of the frame connecting mechanism 16 can be simplified.

[0049] In this embodiment, shims 22 are disposed between the other end 20C of wedge member 20 and block body 21, or between guide member 17 and block body 21. With this configuration, the position of wedge member 20 relative to flange portion 7A can be finely adjusted depending on the number of shims 22, and wedge member 20 can be reliably brought into contact with both guide member 17 and flange portion 7A.

[0050] 12 to 16 show a second embodiment of the present invention. This embodiment is characterized in that the stopper member constituting the frame connecting mechanism includes a stopper body that is movable in the same direction as the wedge member, and a pressing member that presses the stopper body toward the wedge member. In the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and their description will be omitted.

[0051] In this embodiment, multiple (three) frame connection mechanisms 31 are provided between the flange portion 7A of the left front mounting leg 7 and the left side frame 11. That is, one frame connection mechanism 31 is disposed at the rear of the flange portion 7A, and two frame connection mechanisms 31 are disposed at the front of the flange portion 7A, side by side in the left-right direction and integrated together.

[0052] 14 to 16, a frame connection mechanism 31 according to the present embodiment includes a guide member 32, a wedge member 33, and a stopper member 34. However, it differs from the frame connection mechanism 16 according to the first embodiment in that the stopper member 34 is composed of a stopper body 35 and a pressure bolt 36.

[0053] The guide member 32 is fixed to the upper surface 11A of the left side frame 11 adjacent to the rear side of the flange portion 7A provided on the left front mounting leg 7, and movably supports a wedge member 33 (described below). The guide member 32 is formed in a block shape having an upper surface 32A, a lower surface 32B, a front surface 32C, a rear surface 32D, and left and right side surfaces 32E. A bottomed wedge fitting hole 32F extending from the front surface 32C to the rear surface 32D is formed in the middle of the guide member 32 in the left-right direction, and the wedge fitting hole 32F is a circular hole with a circular cross-section. The guide member 32 is formed with multiple (four) bolt insertion holes 32G that penetrate vertically from the upper surface 32A to the lower surface 32B on both left and right sides of the wedge fitting hole 32F. The guide member 32 is fixed to the upper surface 11A of the left side frame 11 by screwing the bolt 18 inserted into the bolt insertion hole 32G into the left side frame 11.

[0054] The front side of the guide member 32 is formed with a notch 32H, which is cut out by carving out the lower surface 32B and the left and right side surfaces 32E from the front surface 32C toward the rear surface 32D. As shown in FIG. 15 , when the guide member 32 is fixed to the left side frame 11 with the bolt 18, the notch 32H of the guide member 32 is positioned above the flange-side inclined surface 7C of the flange portion 7A. This forms a space 19 between the front end of the guide member 32 and the flange-side inclined surface 7C of the flange portion 7A, extending in the longitudinal direction (front-rear direction) of the left side frame 11 and continuing from the wedge fitting hole 32F. The rear surface 32D of the guide member 32 is formed with a bolt hole (internal thread hole) 32J that penetrates from the outside of the guide member 32 into the wedge fitting hole 32F. The bolt hole 32J is positioned concentrically with the wedge fitting hole 32F and receives a pressure bolt 36 (described later) threaded therein.

[0055] The wedge member 33 is provided in the wedge fitting hole 32F of the guide member 32. The wedge member 33 is formed in a cylindrical shape with a circular cross section and a diameter equal to the diameter of the wedge fitting hole 32F, and is slidably inserted into the wedge fitting hole 32F while being movable relative to the left side frame 11 and the left front mounting leg 7. A wedge-side inclined surface 33B inclined relative to the upper surface 11A of the left side frame 11 is formed on one end 33A of the wedge member 33 in the movement direction (front-rear direction). The wedge-side inclined surface 33B has the same inclination angle as the flange-side inclined surface 7C formed on the flange portion 7A, and faces the flange-side inclined surface 7C in the movement direction of the wedge member 33.

[0056] With the wedge member 33 inserted into the wedge fitting hole 32F of the guide member 32, one end 33A of the wedge member 33 is disposed in the space 19 formed between the guide member 32 and the flange-side inclined surface 7C of the flange portion 7A. A cylindrical projection 33D having a smaller diameter than the wedge member 33 is provided on the other end 33C of the wedge member 33 and concentrically with the wedge member 33. The annular end face of the other end 33C of the wedge member 33 centered on the cylindrical projection 33D forms a spring bearing surface 33E.

[0057] The stopper member 34 is provided on the guide member 32 and restricts the movement of the wedge member 33 when the wedge member 33 is in contact with the flange portion 7A and the guide member 32. As shown in Figures 14 to 16, the stopper member 34 is configured to include a stopper main body 35 and a pressure bolt 36.

[0058] The stopper body 35 is disposed in the wedge fitting hole 32F of the guide member 32 and is movable in the same direction as the wedge member 33. The stopper body 35 is formed, for example, from a thick disk having the same outer diameter as the wedge member 33, and is disposed between the rear surface 32D of the guide member 32 and the other end 33C of the wedge member 33 so as to be slidable along the wedge fitting hole 32F. A recess 35A is formed in the end face of the stopper body 35 that is located on the rear surface 32D side of the guide member 32. The recess 35A is formed as a bottomed hole located in the center of the stopper body 35, and the tip of the pressure bolt 36 abuts against the recess 35A. On the other hand, the end face of the stopper body 35 that is located on the wedge member 33 side serves as a spring receiving surface 35B.

[0059] A pressing bolt 36 serving as a pressing member is provided on the rear surface 32D of the guide member 32. The pressing bolt 36 has a threaded portion 36A that screws into the bolt hole 32J of the guide member 32 and a head portion 36B that is disposed outside the guide member 32. When the threaded portion 36A of the pressing bolt 36 is screwed into the bolt hole 32J of the guide member 32, the tip of the threaded portion 36A abuts against the recessed portion 35A of the stopper body 35. When the pressing bolt 36 is rotated in the tightening direction (e.g., clockwise) in this state, the pressing bolt 36 presses the stopper body 35, and the stopper body 35 approaches the wedge member 33 along the wedge fitting hole 32F of the guide member 32.

[0060] A compression spring 37 serving as a biasing member is provided in the wedge fitting hole 32F of the guide member 32, and is disposed between the wedge member 33 and the stopper main body 35. One end of the compression spring 37 abuts against the spring bearing surface 33E of the wedge member 33, and the other end of the compression spring 37 abuts against the spring bearing surface 35B of the stopper main body 35. By rotating the pressure bolt 36 threaded into the bolt hole 32J of the guide member 32 in the tightening direction, the stopper main body 35 moves toward the wedge member 33. At this time, the compression spring 37 contracts between the stopper main body 35 and the wedge member 33, applying a spring force to the wedge member 33. As a result, the wedge-side inclined surface 33B of the wedge member 33 can be pressed against the flange-side inclined surface 7C of the flange portion 7A with an appropriate pressing force (spring force), and the wedge-side inclined surface 33B can be brought into contact with the flange-side inclined surface 7C (see FIG. 14 ). The stopper body 35 and the pressing bolt 36 restrict the movement of the wedge member 33 via the compression spring 37, and the wedge member 33 is held in a position where it abuts against the flange portion 7A and the guide member 32.

[0061] 15, when the stopper body 35 abuts against the rear surface 32D of the guide member 32, the compression spring 37 assumes its natural length and does not apply spring force to the wedge member 33. This allows the wedge-side inclined surface 33B of the wedge member 33 to be separated from the flange-side inclined surface 7C of the flange portion 7A.

[0062] The compression spring 37 is not an essential component, as it presses the wedge-side inclined surface 33B of the wedge member 33 against the flange-side inclined surface 7C of the flange portion 7A with an appropriate pressing force. That is, for example, a long pressing bolt 36 may be used to directly contact the stopper body 35 against the wedge member 33, and the amount of tightening of the pressing bolt 36 may be adjusted to cause the wedge-side inclined surface 33B of the wedge member 33 to contact the flange-side inclined surface 7C of the flange portion 7A without any gap.

[0063] The frame connection mechanism 31 according to the second embodiment has the configuration described above. Next, we will explain the process of releasing the connection between the left side frame 11 and the left front mounting leg 7 by the frame connection mechanism 31 in order to change the width dimension of the lower running body 2 from dimension B when contracted to dimension A when expanded.

[0064] When the frame connecting mechanism 31 connects the flange portion 7A of the left front mounting leg 7 and the left side frame 11, as shown in Figure 14, the stopper body 35, which is disposed in the wedge fitting hole 32F of the guide member 32, is pressed toward the wedge member 33 by the pressure bolt 36. At this time, the compression spring 37, which is disposed between the wedge member 33 and the stopper body 35, applies a spring force to the wedge member 33. As a result, the wedge member 33 is held in a position where the wedge-side inclined surface 33B abuts against the flange-side inclined surface 7C of the flange portion 7A.

[0065] To release this connection, the pressure bolt 36 is rotated in the loosening direction (e.g., counterclockwise). As a result, as shown in Figure 15, the stopper body 35 comes into contact with the rear surface 32D of the guide member 32, and the compression spring 37 extends to its natural length. This allows the wedge-side inclined surface 33B of the wedge member 33 to separate from the flange-side inclined surface 7C of the flange portion 7A.

[0066] In this way, by separating the wedge-side inclined surface 33B of the wedge member 33 from the flange-side inclined surface 7C of the flange portion 7A, the connection between the left front mounting leg 7 and the left side frame 11 is released. Similarly, by releasing the connection between the left rear mounting leg 8 and the left side frame 11 using the frame connection mechanism 31, the left side frame 11 becomes movable in the left-right direction. This allows the width dimension of the lower running body 2 to be changed from the retracted dimension B to the extended dimension A.

[0067] After changing the width dimension of the lower running body 2 to the expanded dimension A, the left side frame 11 is connected to the flange portion 7A of the left front mounting leg 7 using the frame connection mechanism 31. Specifically, the pressure bolt 36 is rotated in the tightening direction to bring the stopper main body 35 closer to the wedge member 33. At this time, the compression spring 37 applies a spring force to the wedge member 33, causing the wedge-side inclined surface 33B of the wedge member 33 to abut against the flange-side inclined surface 7C with an appropriate pressing force (spring force) within the space 19 formed between the guide member 32 and the flange portion 7A. As a result, the stopper main body 35 and the pressure bolt 36 restrict the movement of the wedge member 33 via the compression spring 37. As a result, the wedge member 33 can be inserted between the guide member 32 (the inner surface of the wedge fitting hole 32F) and the flange portion 7A (the flange-side inclined surface 7C) and abutted against both, and the left front mounting leg 7 and the left side frame 11 can be connected without any gaps using the wedge member 33.

[0068] Similarly, the left rear mounting leg 8 and the left side frame 11 are connected using the frame connecting mechanism 31. As a result, when the width dimension of the lower running body 2 is changed to the expanded dimension A, the left front mounting leg 7 and the left rear mounting leg 8 can be connected to the left side frame 11 using the frame connecting mechanism 31 without any gaps.

[0069] In the second embodiment, the stopper member 34 of the frame connecting mechanism 31 includes a stopper body 35 that is movable in the same direction as the wedge member 33, and a pressing bolt 36 (pressing member) that presses the stopper body 35 toward the wedge member 33. With this configuration, by tightening the pressing bolt 36 into the bolt hole 32J of the guide member 32, the wedge member 33 is pressed against the flange portion 7A of the left front mounting leg 7 via the stopper body 35, and movement of the wedge member 33 can be restricted at the position where the wedge-side inclined surface 33B abuts against the flange-side inclined surface 7C of the flange portion 7A. As a result, the wedge member 33 can be inserted between the guide member 32 and the flange portion 7A and abutted against both, and the left front mounting leg 7 and the left side frame 11 can be connected using the wedge member 33 without any gaps.

[0070] Moreover, in the second embodiment, a compression spring 37 (biasing member) that biases the wedge member 33 in a direction that brings it into contact with the flange portion 7A is provided between the wedge member 33 and the stopper main body 35. With this configuration, the compression spring 37 applies a spring force to the wedge member 33, thereby pressing the wedge-side inclined surface 33B of the wedge member 33 against the flange-side inclined surface 7C of the flange portion 7A with an appropriate pressing force (spring force). As a result, the wedge-side inclined surface 33B can always be in contact with the flange-side inclined surface 7C, and the left front mounting leg 7 and the left side frame 11 can be connected without any gaps.

[0071] 17 to 22 show a third embodiment of the present invention. This embodiment is characterized in that the stopper member constituting the frame connecting mechanism includes a stopper body that is movable in the same direction as the wedge member, a pressing member that is movable in a direction intersecting the movement direction of the wedge member and presses the stopper body toward the wedge member by contacting the stopper member, and a movement mechanism that moves the pressing member. In the third embodiment, the same components as those in the first embodiment described above are designated by the same reference numerals, and their description will be omitted.

[0072] In this embodiment, multiple (three) frame connection mechanisms 41 are provided between the flange portion 7A of the left front mounting leg 7 and the left side frame 11. That is, one frame connection mechanism 41 is disposed at the rear of the flange portion 7A, and two frame connection mechanisms 41 are disposed at the front of the flange portion 7A, side by side in the left-right direction and integrated together.

[0073] 19 to 22 , a frame connection mechanism 41 according to the present embodiment includes a guide member 42, a wedge member 43, and a stopper member 44. However, it differs from the frame connection mechanism 16 according to the first embodiment in that the stopper member 44 is configured by a stopper main body 45, a pressing tool 46, and a pressing tool moving mechanism 47.

[0074] The guide member 42 is fixed to the upper surface 11A of the left side frame 11 adjacent to the rear side of the flange portion 7A provided on the left front mounting leg 7, and movably supports a wedge member 43 (described below). The guide member 42 is formed in a block shape having an upper surface 42A, a lower surface 42B, a front surface 42C, a rear surface 42D, a left side surface 42E, and a right side surface 42F. A bottomed wedge fitting hole 42G extending from the front surface 42C to the rear surface 42D is formed in the middle of the guide member 42 in the left-right direction, and the wedge fitting hole 42G is a circular hole with a circular cross-section. The guide member 42 is formed with multiple (four) bolt insertion holes 42H that penetrate vertically from the upper surface 42A to the lower surface 42B on both left-right sides of the wedge fitting hole 42G. The guide member 42 is fixed to the upper surface 11A of the left side frame 11 by screwing the bolt 18 inserted into the bolt insertion hole 42H into the left side frame 11.

[0075] A notch 42J is formed on the front side of the guide member 42 by cutting out the lower surface 42B, left side surface 42E, and right side surface 42F from the front surface 42C toward the rear surface 42D. As shown in Figure 21 , when the guide member 42 is fixed to the left side frame 11 with bolts 18, the notch 42J of the guide member 42 is positioned above the flange-side inclined surface 7C of the flange portion 7A. As a result, a space 19 is formed between the front end of the guide member 42 and the flange-side inclined surface 7C of the flange portion 7A, extending in the length direction (front-rear direction) of the left side frame 11 and continuing from the wedge fitting hole 42G.

[0076] A press tool fitting hole 42K is formed in the right side surface 42F of the guide member 42, extending horizontally toward the left side surface 42E. The press tool fitting hole 42K is a bottomed rectangular hole with a rectangular cross section extending in the left-right direction, and is perpendicular to and communicates with the wedge fitting hole 42G. A press tool 46, described below, is slidably inserted into the press tool fitting hole 42K. A bolt insertion hole 42L is formed in the left side surface 42E of the guide member 42, extending from the outside of the guide member 42 toward the right side surface 42F. The bolt insertion hole 42L passes through the press tool fitting hole 42K, and an operating bolt 49, described below, is inserted through the bolt insertion hole 42L. In addition, two bolt holes (internal thread holes) 42M are formed in the left side surface 42E of the guide member 42, sandwiching the bolt insertion hole 42L from the front-rear direction.

[0077] A return member mounting groove 42N is formed in the lower surface 42B of the guide member 42. The return member mounting groove 42N is located below (directly below) the center of the wedge fitting hole 42G and extends in the front-to-rear direction from the rear surface 42D to the front surface 42C of the guide member 42. The return member mounting groove 42N is formed as a linear groove with a groove width smaller than the hole diameter of the wedge fitting hole 42G, and communicates with the lower ends of the wedge fitting hole 42G and the pressing tool fitting hole 42K. A return member 51, described later, is located in the return member mounting groove 42N so as to be movable in the front-to-rear direction.

[0078] The wedge member 43 is provided in the wedge fitting hole 42G of the guide member 42. The wedge member 43 is formed in a cylindrical shape with a circular cross section and a diameter equal to the diameter of the wedge fitting hole 42G, and is slidably inserted into the wedge fitting hole 42G while being movable relative to the left side frame 11 and the left front mounting leg 7. A wedge-side inclined surface 43B inclined with respect to the upper surface 11A of the left side frame 11 is formed on one end 43A of the wedge member 43 in the movement direction. The wedge-side inclined surface 43B has the same inclination angle as the flange-side inclined surface 7C formed on the flange portion 7A, and faces the flange-side inclined surface 7C in the movement direction of the wedge member 43.

[0079] With the wedge member 43 inserted into the wedge fitting hole 42G of the guide member 42, one end 43A of the wedge member 43 is disposed in the space 19 formed between the guide member 42 and the flange-side inclined surface 7C of the flange portion 7A. A recessed portion 43D recessed toward the center is formed on the outer peripheral surface of the other end 43C side of the wedge member 43. The recessed portion 43D opens into the return member attachment groove 42N of the guide member 42, and engages with a tip protrusion 51A of the return member 51, which will be described later.

[0080] The stopper member 44 is provided on the guide member 42 and restricts movement of the wedge member 43 when the wedge member 43 is in contact with the flange portion 7A and the guide member 42. As shown in Figures 19 to 22, the stopper member 44 is configured to include a stopper main body 45, a pressing tool 46, and a pressing tool moving mechanism 47.

[0081] The stopper body 45 is disposed in the wedge fitting hole 42G of the guide member 42 and is movable in the same direction as the wedge member 43. The stopper body 45 is formed, for example, of a cylinder having the same outer diameter as the wedge member 43, and one end 45A of the stopper body 45 in the movement direction faces the other end 43C of the wedge member 43. A stopper-side inclined surface 45C is formed on the other end 45B of the stopper body 45 and is disposed in the pressing tool fitting hole 42K of the guide member 42. The stopper-side inclined surface 45C is inclined so that the axial dimension of the stopper body 45 gradually decreases from the left side surface 42E to the right side surface 42F of the guide member 42.

[0082] A groove 45D is formed in the vertical center of the stopper body 45 by cutting the stopper body 45 horizontally from the other end 45B toward the one end 45A. The groove 45D opens at the other end 45B of the stopper body 45 and accommodates an operating bolt 49, which will be described later. A recessed portion 45E is formed in the outer peripheral surface of the stopper body 45, recessed toward the center. The recessed portion 45E opens into the return member mounting groove 42N of the guide member 42 and engages with the intermediate protrusion 51B of the return member 51.

[0083] The pressing tool 46 is provided in the pressing tool fitting hole 42K of the guide member 42 and is movable in a direction (left-right direction) that intersects at a right angle with the movement direction of the wedge member 43. The pressing tool 46 is made of, for example, a rectangular prism-shaped block body having a cross-sectional shape similar to that of the pressing tool fitting hole 42K and moves along the pressing tool fitting hole 42K. A pressing-side inclined surface 46A is formed on the surface of the pressing tool 46 facing the front surface 42C of the guide member 42. The pressing-side inclined surface 46A has the same inclination angle as the stopper-side inclined surface 45C of the stopper main body 45 and faces the stopper-side inclined surface 45C in the movement direction of the pressing tool 46.

[0084] The pressing tool moving mechanism 47 is provided on the guide member 42 and the pressing tool 46, and moves the pressing tool 46 relative to the guide member 42. The pressing tool moving mechanism 47 is composed of a bolt hole (internal thread hole) 48 provided in the pressing tool 46, and an operating bolt 49 that is rotatably supported on the guide member 42 and screws into the bolt hole 48.

[0085] The bolt hole 48 constituting the pressing tool moving mechanism 47 is formed in the pressing tool 46. The bolt hole 48 is disposed concentrically with the bolt insertion hole 42L formed in the guide member 42, and passes through in the movement direction (left-right direction) of the pressing tool 46. A threaded portion 49A of an operating bolt 49 is screwed into the bolt hole 48.

[0086] The operating bolt 49, which constitutes the pressing tool moving mechanism 47 together with the bolt hole 48, is inserted through the bolt insertion hole 42L of the guide member 42 and protrudes into the pressing tool fitting hole 42K. The operating bolt 49 has a threaded portion 49A that screws into the bolt hole 48 of the pressing tool 46 inside the pressing tool fitting hole 42K, and a head portion 49B that is disposed outside the guide member 42. A disk-shaped flange portion 49C is fixed integrally to the vicinity of the head portion 49B, and the flange portion 49C is rotatably supported by a bolt support member 50.

[0087] The bolt support member 50 is disposed on the left side surface 42E of the guide member 42. As shown in Figures 18 and 20, the bolt support member 50 is attached to the left side surface 42E of the guide member 42 by two bolts 50A that are threaded into bolt holes 42M of the guide member 42. A flange fitting hole 50B into which the flange 49C of the operating bolt 49 is rotatably fitted, and a cover portion 50C that sandwiches the flange 49C between the bolt support member 50 and the left side surface 42E of the guide member 42 are formed in the center of the bolt support member 50.

[0088] The operating bolt 49 is inserted through the bolt insertion hole 42L of the guide member 42 and protrudes into the pressing tool fitting hole 42K. The threaded portion 49A of the operating bolt 49 is threaded into the bolt hole 48 of the pressing tool 46 within the pressing tool fitting hole 42K, and the head 49B and flange 49C of the operating bolt 49 are disposed outside the guide member 42 (left side surface 42E). In this state, the bolt support member 50 is fixed to the left side surface 42E of the guide member 42 by two bolts 50A threaded into the bolt holes 42M of the guide member 42. As a result, the flange 49C of the operating bolt 49 is rotatably fitted into the flange fitting hole 50B of the bolt support member 50 and is axially positioned by the cover portion 50C and the left side surface 42E of the guide member 42. In this way, the operating bolt 49 is rotatably supported by the guide member 42 with the threaded portion 49 A screwed into the bolt hole 48 of the pressing tool 46 .

[0089] Therefore, by rotating the head 49B of the operating bolt 49 in the tightening direction (for example, clockwise), the pressing tool 46 moves toward the left side surface 42E along the pressing tool fitting hole 42K of the guide member 42. The pressing side inclined surface 46A of the moving pressing tool 46 comes into contact with the stopper side inclined surface 45C of the stopper body 45, and the pressing tool 46 is inserted between the stopper side inclined surface 45C of the stopper body 45 and the inner circumferential surface of the pressing tool fitting hole 42K. The stopper body 45 is pressed by the pressing side inclined surface 46A of the pressing tool 46, and moves along the wedge fitting hole 42G of the guide member 42 toward the wedge member 43. As a result, the wedge member 43 is pressed by the stopper body 45 and moves toward the flange portion 7A of the left front mounting leg 7, and the wedge side inclined surface 43B of the wedge member 43 can abut against the flange side inclined surface 7C within the space 19 formed between the guide member 42 and the flange portion 7A (see Figure 19).

[0090] On the other hand, by rotating the head 49B of the operating bolt 49 in the loosening direction (e.g., counterclockwise), the pressing tool 46 moves toward the right side surface 42F along the pressing tool fitting hole 42K of the guide member 42. As a result, the pressing-side inclined surface 46A of the pressing tool 46 disengages from the stopper-side inclined surface 45C of the stopper main body 45. When the pressing tool 46 and the stopper main body 45 are moved in accordance with the rotation of the operating bolt 49, the threaded portion 49A of the operating bolt 49 is accommodated in the groove 45D of the stopper main body 45.

[0091] The return member 51 is disposed between the upper surface 11A of the left side frame 11 and the guide member 42 so as to be movable in the front-rear direction. The return member 51 moves the wedge member 43, which is in contact with the flange portion 7A (flange-side inclined surface 7C), in a direction away from the flange portion 7A. The return member 51 is formed, for example, using an elongated flat plate extending in the front-rear direction and is movable along a return member mounting groove 42N formed in the guide member 42. One end of the return member 51 disposed in the return member mounting groove 42N is provided with a tip protrusion 51A that protrudes upward, and the tip protrusion 51A engages with the recessed portion 43D of the wedge member 43. In addition, one end of the return member 51 is provided with an intermediate protrusion 51B adjacent to the rear side of the tip protrusion 51A, and the intermediate protrusion 51B engages with the recessed portion 45E of the stopper body 45.

[0092] Meanwhile, the other end 51C of the return member 51 protrudes from the rear surface 42D of the guide member 42 to the outside of the guide member 42. A handle 51D made of a cylindrical rod is fixed to the other end 51C of the return member 51 by welding or other means. The return member 51 can be moved in a direction away from the flange portion 7A of the left front mounting leg 7 while gripping the handle 51D. At this time, the tip projection 51A of the return member 51 engages with the recessed portion 43D of the wedge member 43, and the middle projection 51B of the return member 51 engages with the recessed portion 45E of the stopper body 45.

[0093] Therefore, when the operating bolt 49 (head 49B) is rotated in the loosening direction and the pressing-side inclined surface 46A of the pressing tool 46 is disengaged from the stopper-side inclined surface 45C of the stopper body 45, the wedge member 43 can be moved in a direction away from the flange portion 7A by the return member 51. As a result, as shown in Fig. 21 , the wedge-side inclined surface 43B of the wedge member 43 can be disengaged from the flange-side inclined surface 7C of the flange portion 7A.

[0094] The frame connection mechanism 41 according to the third embodiment has the configuration described above. Next, we will explain the process of releasing the connection between the left side frame 11 and the left front mounting leg 7 by the frame connection mechanism 41 in order to change the width dimension of the lower running body 2 from dimension B when contracted to dimension A when expanded.

[0095] 19 and 20, when the frame connecting mechanism 41 connects the flange portion 7A of the left front mounting leg 7 and the left side frame 11, the stopper body 45 disposed in the wedge fitting hole 42G of the guide member 42 is pressed toward the wedge member 43 by the pressing tool 46. As a result, the wedge member 43 is held in a position where the wedge-side inclined surface 43B abuts against the flange-side inclined surface 7C of the flange portion 7A.

[0096] To release this connection, the operating bolt 49 is rotated in the loosening direction. As a result, as shown in FIG. 22 , the pressing tool 46 moves along the pressing tool fitting hole 42K of the guide member 42 toward the right side surface 42F and out of the movement range of the stopper body 45. In this state, the return member 51 is moved along the return member mounting groove 42N of the guide member 42 in a direction away from the flange portion 7A of the left front mounting leg 7. The tip projection 51A of the return member 51 engages with the recessed portion 43D of the wedge member 43, and the middle projection 51B of the return member 51 engages with the recessed portion 45E of the stopper body 45. Therefore, the wedge member 43 and the stopper body 45 can be moved along with the return member 51 in a direction away from the flange portion 7A. This reliably disengages the wedge-side inclined surface 43B of the wedge member 43 from the flange-side inclined surface 7C of the flange portion 7A.

[0097] In this way, by separating the wedge-side inclined surface 43B of the wedge member 43 from the flange-side inclined surface 7C of the flange portion 7A, the connection between the left front mounting leg 7 and the left side frame 11 is released. Similarly, by releasing the connection between the left rear mounting leg 8 and the left side frame 11 using the frame connection mechanism 41, the left side frame 11 becomes movable in the left-right direction. This allows the width dimension of the lower running body 2 to be changed from the retracted dimension B to the extended dimension A.

[0098] After changing the width dimension of the lower running body 2 to the expanded dimension A, the left side frame 11 is connected to the flange portion 7A of the left front mounting leg 7 using the frame connection mechanism 41. Specifically, the operating bolt 49 is rotated in the tightening direction to move the pressing tool 46 toward the left side surface 42E along the pressing tool fitting hole 42K of the guide member 42. At this time, the pressing side inclined surface 46A of the moving pressing tool 46 abuts against the stopper side inclined surface 45C of the stopper main body 45, causing the stopper main body 45 to move toward the wedge member 43 along the wedge fitting hole 42G of the guide member 42.

[0099] As a result, the wedge member 43 is pressed by the stopper body 45 and moves toward the flange portion 7A of the left front mounting leg 7, and the wedge-side inclined surface 43B of the wedge member 43 abuts against the flange-side inclined surface 7C in the space 19 formed between the guide member 42 and the flange portion 7A. At this time, the stopper body 45 abuts against the wedge member 43, and the pressing-side inclined surface 46A of the pressing tool 46 fitted in the pressing tool fitting hole 42K of the guide member 42 abuts against the stopper-side inclined surface 45C of the stopper body 45. Therefore, the movement of the wedge member 43 is restricted by the stopper body 45 and the pressing tool 46. As a result, the wedge member 43 can be inserted between the guide member 42 (the inner surface of the wedge fitting hole 42G) and the flange portion 7A (the flange-side inclined surface 7C) and abutted against both, and the left front mounting leg 7 and the left side frame 11 can be connected without any gaps using the wedge member 43.

[0100] Similarly, the left rear mounting leg 8 and the left side frame 11 are connected using the frame connecting mechanism 41. As a result, when the width dimension of the lower running body 2 is changed to the expanded dimension A, the left front mounting leg 7 and the left rear mounting leg 8 can be connected to the left side frame 11 using the frame connecting mechanism 41 without any gaps.

[0101] Here, in the third embodiment, the stopper member 44 of the frame connecting mechanism 41 is configured to include a stopper main body 45 that is arranged to be movable in the same direction as the wedge member 43, a pressing tool 46 that is arranged to be movable in a direction intersecting the movement direction of the wedge member 43 and presses the stopper main body 45 toward the wedge member 43 by abutting against the stopper main body 45, and a pressing tool moving mechanism 47 that moves the pressing tool 46, and the pressing tool moving mechanism 47 is configured by a bolt hole 48 formed in the pressing tool 46 and an operating bolt 49 that is rotatably supported by the guide member 42 and threaded into the bolt hole 48 of the pressing tool 46.

[0102] With this configuration, for example, by rotating the operating bolt 49 in the tightening direction and moving the pressing tool 46 along the pressing tool fitting hole 42K of the guide member 42, the pressing-side inclined surface 46A of the pressing tool 46 can be brought into contact with the stopper-side inclined surface 45C of the stopper main body 45. As a result, the stopper main body 45 moves along the wedge fitting hole 42G of the guide member 42 and presses the wedge member 43 toward the flange portion 7A. In this case, the amount of movement of the wedge member 43 can be finely adjusted according to the amount of tightening of the operating bolt 49. As a result, the wedge-side inclined surface 43B of the wedge member 43 can be brought into contact with the flange-side inclined surface 7C of the flange portion 7A with an appropriate pressing force, thereby connecting the left front mounting leg 7 and the left side frame 11 without any gaps. Furthermore, when the pressing-side inclined surface 46A of the pressing tool 46 abuts against the stopper-side inclined surface 45C of the stopper member 45, a large pressing force acts on the wedge member 43 due to the wedge principle. Therefore, the left front mounting leg 7 and the left side frame 11 can be fixed reliably with a high degree of freedom.

[0103] Furthermore, in the third embodiment, a recess 43D is provided on the outer peripheral surface of the wedge member 43 of the frame connecting mechanism 41, and the guide member 42 is provided with a tip projection 51A provided on one longitudinal end that engages with the recess 43D and a return member 51 whose other longitudinal end 51C protrudes outside the guide member 42 and moves the wedge member 43 in a direction away from the flange portion 7A. With this configuration, the wedge-side inclined surface 43B of the wedge member 43 can be reliably released from the flange-side inclined surface 7C of the flange portion 7A, making it possible to easily and quickly release the connection between the left front mounting leg 7 and the left side frame 11.

[0104] The frame connection mechanism 41 according to the third embodiment is illustrated as including a return member 51 that moves the wedge member 43 in a direction away from the flange portion 7A. However, the return member 51 can also be applied to the frame connection mechanism 16 according to the first embodiment and the frame connection mechanism 31 according to the second embodiment.

[0105] Furthermore, the third embodiment illustrates a case in which the pressing tool 46 moves in a direction that intersects at a right angle (orthogonal) with the moving direction of the wedge member 43. However, the present invention is not limited to this, and for example, a pressing tool that moves in a direction that intersects at an acute angle with the moving direction of the wedge member may be used.

[0106] In the embodiments, the wedge members 20, 33, 43 are formed using cylinders with a circular cross section. However, the present invention is not limited to this, and the wedge members may be formed using, for example, prisms with a polygonal cross section, truncated cones with a circular cross section, or truncated pyramids with a polygonal cross section.

[0107] Furthermore, in the embodiment, the frame connecting mechanism 16 that connects the flange portion 7A of the left front mounting leg 7 to the left side frame 11 is illustrated as being disposed on the upper surface 11A of the left side frame 11. However, the present invention is not limited to this, and the frame connecting mechanism 16 may be disposed on, for example, a side surface in the left or right direction of the left side frame 11. This also applies to the frame connecting mechanism 16 that connects the flange portion 8A of the left rear mounting leg 8 to the left side frame 11, the frame connecting mechanism 16 that connects the flange portion 9A of the right front mounting leg 9 to the right side frame 12, and the frame connecting mechanism 16 that connects the flange portion 10A of the right rear mounting leg 10 to the right side frame 12.

[0108] Furthermore, in the embodiment, the flange-side inclined surface 7C is integrally formed with the flange portion 7A of the left front mounting leg 7. However, the present invention is not limited to this, and for example, a separate member having an inclined surface may be fixed to the flange portion by means of welding or the like. The same applies to the left rear mounting leg 8, the right front mounting leg 9, and the right rear mounting leg 10.

[0109] DESCRIPTION OF SYMBOLS 2 Lower traveling body 4 Upper rotating body 6 Center frame 7 Left front mounting leg 7A, 8A, 9A, 10A Flange portion 7C, 8B, 9B, 10B Flange side inclined surface 8 Left rear mounting leg 9 Right front mounting leg 10 Right rear mounting leg 11 Left side frame 11A, 12A Upper surface (surface) 12 Right side frame 16, 31, 41 Frame connecting mechanism 17, 32, 42 Guide member 17F, 32F, 42G Wedge fitting hole (circular hole) 19 Space 20, 33, 43 Wedge member 20A, 33A, 43A One end 20B, 33B, 43B Wedge side inclined surface 20C, 33C, 43C Other end 21 Block body (stopper member) 22 Shim 34, 44 Stopper member 35, 45 Stopper body 36 Pressing bolt (pressing member) 37 Compression spring (biasing member) 43D Recessed portion 46 Pressing tool 47 Pressing tool moving mechanism 48 Bolt hole 49 Operating bolt 51 Returning member

Claims

1. A work machine comprising a self-propelled lower running body and an upper rotating body rotatably mounted on the lower running body, the lower running body comprising a center frame having a frame main body to which the upper rotating body is attached and mounting legs which extend left and right from the frame main body and have flange portions at their tips, side frames which are arranged on both left and right sides of the center frame and attached to the flange portions, and a frame connecting mechanism which connects the side frames to the mounting legs, wherein the frame connecting mechanism comprises: a guide member which is attached to the side frame and forms a space between the flange portions and the guide member; a wedge member which is provided between the flange portions and the guide member and moves along the guide member within the space to abut against the flange portions and the guide member; and a stopper member which is provided on the guide member and restricts movement of the wedge member at a position where the wedge member abuts against the flange portions and the guide member.

2. A work machine as described in claim 1, characterized in that the flange portion is provided with a flange-side inclined surface that is inclined with respect to the surface of the side frame, and the wedge member is provided with a wedge-side inclined surface that faces the flange-side inclined surface in the movement direction of the wedge member and is capable of surface contact with the flange-side inclined surface.

3. A work machine as described in claim 2, characterized in that the wedge member is formed in a cylindrical shape with a circular cross section, and the guide member is formed with a circular hole into which the wedge member is slidably inserted.

4. The work machine described in claim 1, characterized in that one end of the wedge member in the moving direction abuts against the flange portion, and the stopper member is detachably provided between the other end of the wedge member in the moving direction and the guide member, and is constituted by a block body that abuts against the other end of the wedge member when the one end of the wedge member abuts against the flange portion.

5. A work machine according to claim 4, characterized in that a shim is disposed between the other end of the wedge member and the block body, or between the guide member and the block body.

6. A work machine as described in claim 1, characterized in that the stopper member includes a stopper body that is movable in the same direction as the wedge member, and a pressing member that presses the stopper body toward the wedge member.

7. A work machine according to claim 6, characterized in that a biasing member is provided between said wedge member and said stopper body, for biasing said wedge member in a direction in which it abuts against said flange portion.

8. The work machine according to claim 1, characterized in that the stopper member includes a stopper body that is movable in the same direction as the wedge member, a pressing tool that is movable in a direction intersecting the movement direction of the wedge member and presses the stopper body toward the wedge member by abutting against the stopper body, and a pressing tool moving mechanism that moves the pressing tool.

9. A work machine as described in claim 8, characterized in that the pressing tool moving mechanism is composed of a bolt hole formed in the pressing tool and a bolt rotatably supported by the guide member and screwed into the bolt hole of the pressing tool.

10. A work machine as described in claim 1, characterized in that a recess is provided on the outer peripheral surface of the wedge member, and the guide member is provided with a return member having one end in the longitudinal direction that engages with the recess and the other end in the longitudinal direction that protrudes outside the guide member, for moving the wedge member in a direction away from the flange portion.

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