Work vehicle and blade support structure

Abstract

To provide a work vehicle capable of suppressing an accumulation of sediment.SOLUTION: A motor grader 1 includes a rear frame 22, a front frame 21, a blade 24, and a support mechanism 23. The front frame 21 is rotatably connected to the rear frame 22. The support mechanism 23 supports the blade 24 on the front frame 21 so as to be slidable along the width direction of the blade 24. The support mechanism 23 includes upper support parts 73, 82 that support an upper end part 91a of the blade 24, and a lower support part 74 that supports the blade 24 rearward and below the upper support parts 73, 82.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a work vehicle and a blade support structure. [Background technology]

[0002] In a motor grader, the position of a blade disposed between the front and rear wheels is configured to be slidably adjustable relative to a frame (see, for example, Patent Document 1).

[0003] In the motor grader shown in Patent Document 1, a support structure is rotatably arranged on an arm extending downward from a rotating ring gear, and a blade is supported on the support structure so that its position can be adjusted. An upper slide rail and a lower slide rail are provided along the width direction on the rear surface of the blade, and an upper bearing arrangement and a lower bearing arrangement are provided on the support structure so as to sandwich the upper slide rail and the lower slide rail from above and below. This structure allows the position of the blade to be adjusted relative to the support structure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Pat. No. 6,904,978 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the structure of Patent Document 1, dirt and sand that went over the blade would accumulate on the upper slide rail, which required cleaning. The upper slide rail was provided along the width direction of the blade, so the cleaning range was wide, and because it was provided on the back side of the blade, it was difficult to access and cleaning was time-consuming.

[0006] An object of the present disclosure is to provide a work vehicle and a blade support structure capable of suppressing the accumulation of soil and sand. [Means for solving the problem]

[0007] A work vehicle according to a first aspect of the present disclosure includes a rear frame, a front frame, a blade, and a support mechanism. The front frame is rotatably connected to the rear frame. The support mechanism supports the blade on the front frame so that the blade can slide along the width direction of the blade. The support mechanism has a first support portion that supports an upper end of the blade, and a second support portion that supports the blade rearward and below the first support portion.

[0008] A blade support structure according to a second aspect of the present disclosure is a blade support structure for supporting a blade of a work vehicle having a rear frame and a front frame rotatably connected to the rear frame on the front frame so as to be slidable along the width direction of the blade, and includes a first support portion and a second support portion. The first support portion supports an upper end portion of the blade. The second support portion supports the blade rearward and below the first support portion.

[0009] A work vehicle according to a third aspect of the present disclosure includes a rear frame, a front frame, a blade, and a support mechanism. The front frame is rotatably connected to the rear frame. The support mechanism supports the blade on the front frame so that the blade can slide along the width direction of the blade. The support mechanism has a drawbar, a lift cylinder, and a blade rotation support portion. The drawbar is connected to the front frame so as to be vertically swingable. The lift cylinder swings the drawbar up and down. The blade rotation support portion rotatably supports the blade on the drawbar. In a side view, an upper end of the blade is disposed at a position overlapping a line extending downward from a connection portion of the lift cylinder to the drawbar, or forward of the connection portion in the front-rear direction. Effect of the Invention

[0010] According to the present disclosure, it is possible to provide a work vehicle and a blade support structure capable of suppressing the accumulation of soil and sand. [Brief description of the drawings]

[0011] [Figure 1] 1 is a perspective view of a motor grader according to an embodiment of the present disclosure. FIG. [Diagram 2] 1 is a perspective view showing a blade and a blade rotation support of a motor grader according to an embodiment of the present disclosure. FIG. [Diagram 3] 1 is a side view showing a blade and a blade rotation support of a motor grader according to an embodiment of the present disclosure. FIG. [Figure 4] In FIG. 3, the rotating parts are indicated by two-dot chain lines, and components hidden by these components are indicated by solid lines. [Diagram 5] 2 is a rear view of the blade and blade rotation support of the motor grader according to the embodiment of the present disclosure. FIG. [Figure 6] FIG. 2 is a front view of a blade and a blade pivot support according to an embodiment of the present disclosure. [Figure 7] In FIG. 6, the blades are indicated by two-dot chain lines, and the configuration hidden by the blades is indicated by solid lines. [Figure 8] FIG. 2 is a side cross-sectional view of a blade and a blade pivot support in an embodiment according to the present disclosure. [Figure 9] FIG. 2 is a rear perspective view of a blade according to an embodiment of the present disclosure. [Figure 10] 1 is a side view showing a drawbar, a blade, and a blade rotation support portion of a motor grader according to an embodiment of the present disclosure. FIG. [Figure 11] 11 is a diagram showing a state in which the tilt cylinder is extended from the state shown in FIG. 10 to rotate the blade so that the upper end portion moves downward. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, a motor grader (an example of a work vehicle) and a blade support structure according to an embodiment will be described with reference to the drawings.

[0013] (Overall configuration of Motor Grader 1) 1 is a perspective view of the appearance of a motor grader according to the present embodiment. In the following description, terms such as "up," "down," "left," "right," "front," and "rear" are based on the directions seen by an operator seated in the driver's seat.

[0014] The motor grader 1 includes a frame 10, left and right front wheels 11, left and right rear wheels 12, 13 (two wheels on each side), a work implement 14, a cab 15, and an engine room 16.

[0015] The frame 10 has a front frame 21 and a rear frame 22. The front frame 21 is disposed in front of the rear frame 22. The front frame 21 is connected to the rear frame 22. The front frame 21 is rotatable left and right relative to the rear frame 22. The front frame 21 is supported by left and right front wheels 11. The front frame 21 supports a work machine 14. The rear frame 22 is supported by left and right rear wheels 12, 13. The cab 15 is disposed on the rear frame 22. A driver's seat, operating devices, etc. are disposed in the cab 15. The engine room 16 is disposed on the rear frame 22. The engine room 16 is disposed rearward of the cab 15. An engine is housed in the engine room 16.

[0016] (Work equipment 14) The work implement 14 is attached to the front frame 21. The work implement 14 is disposed below the front frame 21. The work implement 14 is disposed between the left and right front wheels 11 and the left and right rear wheels 12, 13 in the front-rear direction. The work implement 14 has a support mechanism 23 and a blade 24. The support mechanism 23 supports the blade 24 on the front frame 21 so that the blade 24 can swing up and down and left and right, can slide left and right, and can rotate around the rotation axis of a rotating part 41 described later. The blade 24 is supported by the support mechanism 23.

[0017] (Support mechanism 23) The support mechanism 23 has a drawbar 31, a blade pivot support part 32, a lifter bracket 33, a pair of left and right lift cylinders 34, and a drawbar shift cylinder 36. The drawbar 31 is connected to the front end part of the front frame 21 by a ball joint so as to be swingable up and down and left and right. The blade pivot support part 32 is attached to the rear part of the drawbar 31. The blade pivot support part 32 supports the blade 24 to be rotatable on the drawbar 31. The lifter bracket 33 is fixed to the front frame 21. The pair of left and right lift cylinders 34 and the drawbar shift cylinder 36 are connected to the lifter bracket 33.

[0018] The left and right lift cylinders 34 are hydraulic cylinders. The left and right lift cylinders 34 are connected to the drawbar 31 and the lifter bracket 33. Each lift cylinder 34 has a cylinder portion 34a and a piston rod 34b that is movable relative to the cylinder portion 34a. The cylinder portion 34a is connected to the lifter bracket 33. The tip of the piston rod 34b is connected to the drawbar 31. The left and right lift cylinders 34 swing the drawbar 31 up and down by extending and retracting. The drawbar shift cylinder 36 is a hydraulic cylinder. The drawbar shift cylinder 36 swings the drawbar 31 left and right by extending and retracting.

[0019] Fig. 2 is a perspective view showing the blade 24 and the blade pivot support 32. Fig. 3 is a side view of the blade 24 and the blade pivot support 32.

[0020] (Blade rotation support part 32) The blade pivot support portion 32 has a pivot portion 41 and a blade support portion 42. The pivot portion 41 is attached to the rear portion of the drawbar 31. The blade support portion 42 supports the blade 24 on the pivot portion 41.

[0021] (Rotating part 41) The swivel section 41 has a swivel circle 51, a circle rotator 52, support arms 53, 54, a cylinder support 55, reinforcing members 56, 57 (FIG. 5 described later), and a tilt cylinder 58. The swivel circle 51 is rotatably supported at the rear of the drawbar 31. The circle rotator 52 hydraulically drives the swivel circle 51 to rotate. The swivel circle 51 can be driven to rotate in both clockwise and counterclockwise directions when viewed from above the vehicle. The tilt angle of the blade 24 relative to the fore-and-aft direction of the motor grader 1 is adjusted by driving the swivel circle 51 to rotate.

[0022] The support arms 53 and 54 are fixed to the swivel circle 51. The support arms 53 and 54 are configured to be rotatable integrally with the swivel circle 51. The support arm 53 extends rearward from the outer surface of the swivel circle 51 on the left side, and then extends downward. The support arm 54 extends rearward from the outer surface of the swivel circle 51 on the right side, and then extends downward. The support arms 53 and 54 are formed symmetrically opposite to each other. The cylinder support 55 protrudes downward from the rear side of the swivel circle 51. FIG. 4 shows the swivel unit 41 with a two-dot chain line, and shows the configuration hidden by these configurations with a solid line. As shown in FIG. 2 and FIG. 4, the cylinder support 55 rotatably supports the tilt cylinder 58.

[0023] 5 is a rear view of the blade 24 and the blade pivot support portion 32. The reinforcing member 56 connects the pivot circle 51 and the support arm 53, and reinforces the support arm 53. The reinforcing member 56 extends from the underside of the pivot circle 51 to the lower part of the support arm 53.

[0024] The reinforcing member 57 connects the swivel circle 51 and the support arm 54 and reinforces the support arm 54. The reinforcing member 57 extends from the underside of the swivel circle 51 to the lower part of the support arm 53.

[0025] The tilt cylinder 58 is a hydraulic cylinder that expands and contracts by hydraulic pressure. As shown in Figs. 2 and 4, a cylinder portion 58a of the tilt cylinder 58 is rotatably connected to the cylinder support 55. A tip end of a piston rod 58b of the tilt cylinder 58 is rotatably connected to a central support member 65, which will be described later. The expansion and contraction of the tilt cylinder 58 causes the blade 24 to swing about an axis extending in the width direction of the blade 24. Note that, when the blade 24 is arranged along the left-right direction as shown in Fig. 1, the width direction of the blade 24 coincides with the left-right direction.

[0026] (Blade support part 42) The blade support part 42 supports the blade 24 so as to be slidable in the width direction (left-right direction). As shown in Figures 4 and 5, the blade support part 42 has end support members 61, 62 (an example of a support member), a lower connecting member 63, an upper connecting member 64, a central support member 65 (an example of a support member), a slide cylinder 66, and cover members 67, 68 (not shown in Figure 4).

[0027] 4, the end support member 61 supports the blade 24 so as to be slidable in the width direction of the blade 24. The end support member 61 is supported by the support arm 53 so as to be rotatable about an axis parallel to the width direction of the blade 24. The end support member 61 is disposed on the left side of the support arm 53.

[0028] 3, the end support member 61 has a main body portion 71, an upper protrusion portion 72, an upper support portion 73, and a lower support portion 74. The main body portion 71 has a generally triangular shape in a side view, and the front end portion is curved to fit the rear shape of the blade 24. The upper protrusion portion 72 is disposed from the top of the main body portion 71 toward the front. The upper protrusion portion 72 is attached to the main body portion 71.

[0029] FIG. 6 is a view of the blade 24 and the blade rotation support part 32 as viewed from the front side. FIG. 7 is a view in which the blade 24 is shown in FIG. 6 by a two-dot chain line, and the configuration hidden by the blade 24 is shown by a solid line. The upper support part 73 is disposed on the upper protrusion part 72. The upper support part 73 is disposed below the upper protrusion part 72. The upper support part 73 is formed longer in the width direction of the blade 24 than the upper protrusion part 72. The upper support part 73 is formed with a recess 73a (an example of a first recess). As shown in FIG. 3, the recess 73a is formed by recessing the lower end surface of the upper support part 73 toward the front and upper side. The recess 73a is formed along the width direction (left and right direction) of the blade 24. The upper end part 91a of the blade 24 fits into the recess 73a.

[0030] The lower support portion 74 is disposed in front of the lower end of the main body portion 71, as shown in FIG. 3. A recess 74a (an example of a second recess) is formed in the lower support portion 74. The recess 74a is formed by recessing the upper surface of the lower support portion 74 downward. The recess 74a is formed along the width direction (left-right direction) of the blade 24. The rail portion 93 of the blade 24 fits into the recess 74a. The lower support portion 74 is formed to be longer in the blade width direction than the main body portion 71, as shown in FIG. 7.

[0031] As shown in FIG. 3 and FIG. 7, a through hole is formed in the lower part of the main body 71 and the lower part of the support arm 53 along the width direction of the blade 24. A rod-shaped lower connecting member 63 is inserted into the through hole. The end support member 61 can rotate relative to the support arm 53 around the lower connecting member 63. As shown in FIG. 3, a through hole 71a is formed in the upper part of the main body 71 along the circumferential direction around the lower connecting member 63. The front edge of the through hole 71a is shown as a front edge 71b, and the rear edge is shown as a rear edge 71c. A bolt 75 is inserted into the through hole 71a. The bolt 75 is fixed to the support arm 53. When the end support member 61 rotates relative to the support arm 53 in response to the extension and contraction of the tilt cylinder 58, the bolt 75 moves relative to the end support member 61 along the through hole 71a. The case where the end support member 61 rotates relative to the support arm 53 so that the upper support portion 73 moves downward is shown in Figure 3 by arrow A. The case where the end support member 61 rotates relative to the support arm 53 so that the upper support portion 73 moves upward is shown in Figure 3 by arrow B.

[0032] The end support member 62 supports the blade 24 so as to be slidable in the width direction of the blade 24. As shown in FIG. 7, the end support member 62 is supported by the support arm 54 so as to be rotatable about an axis parallel to the width direction of the blade 24. The end support member 62 is disposed on the right side of the support arm 54. The end support member 62 is disposed on the right side, and the end support member 61 is disposed on the left side. The end support member 62 is disposed opposite the end support member 61. The end support member 62 is disposed symmetrically with the end support member 61. The configuration of the end support member 62 is the same as that of the end support member 61, and includes a main body portion 71, an upper protruding portion 72, an upper support portion 73, and a lower support portion 74 as shown in FIG. 7. Unlike the end support member 61, the end support member 62 includes a configuration for holding the bottom side of the slide cylinder 66. The other configurations of the end support member 62 are the same as those of the end support member 61, and therefore detailed description thereof will be omitted.

[0033] As shown in Fig. 7, the lower connecting member 63 connects the end support member 61 and the end support member 62. The lower connecting member 63 is inserted into the support arm 54 and the end support member 62, and the end support member 62 is configured to be rotatable relative to the support arm 54 around the lower connecting member 63 as an axis, similar to the end support member 61. Also, similar to the end support member 61, a bolt 75 is inserted into the through hole 71a of the main body 71. When the end support member 62 rotates with respect to the support arm 54 in response to the extension and contraction of the tilt cylinder 58, the bolt 75 (see Fig. 4) moves relative to the end support member 62 along the through hole 71a.

[0034] As shown in Fig. 4, the upper connecting member 64 connects the end support member 61 and the end support member 62. The upper connecting member 64 is a rod-shaped member. The left end of the upper connecting member 64 is inserted into the upper protrusion 72 of the end support member 61, as shown in Fig. 3. The right end of the upper connecting member 64 is inserted into the upper protrusion 72 of the end support member 62.

[0035] As shown in FIG. 7, the central support member 65 is disposed between the end support member 61 and the end support member 62. FIG. 8 is a side cross-sectional view of the blade 24 and the blade pivot support portion 32. The cross-sectional view of FIG. 8 shows a cross-section in the width direction of the blade 24. The central support member 65 has a main body portion 81 and an upper support portion 82. The main body portion 81 is formed to be curved so as to follow the rear side of the blade 24. A through hole is formed in the lower portion 81a of the main body portion 81 in the left-right direction, and the lower connecting member 63 passes through the lower through hole. A through hole is formed in the upper portion 81b of the main body portion 81 in the left-right direction, and the upper connecting member 64 passes through this through hole. The upper support portion 82 is disposed in front of the upper portion 81b of the main body portion 81. A recess 82a (an example of a first recess) is formed in the upper support portion 82. As shown in FIG. 8, the recess 82a is formed by recessing the lower end surface of the upper support portion 82 toward the front and upper side. The recess 82a is formed along the width direction (left-right direction) of the blade 24. An upper end 91a of the blade 24 fits into the recess 82a. Above the portion of the main body 81 through which the upper connecting member 64 passes, a tip end of the piston rod 58b of the tilt cylinder 58 is rotatably supported.

[0036] The end support member 61, the end support member 62, and the central support member 65 are connected by the upper connecting member 64 and the lower connecting member 63. When the central support member 65 rotates around the lower connecting member 63 due to the extension and contraction of the tilt cylinder 58, the end support member 61 and the end support member 62 connected to the central support member 65 also rotate. In this way, the blade support part 42 rotates due to the extension and contraction of the tilt cylinder 58, and the blade 24 also rotates. The rotation of the blade support part 42 and the blade 24 is regulated by the stroke end of the tilt cylinder 58. Between the most contracted state and the most extended state of the tilt cylinder 58, the blade support part 42 and the blade 24 can rotate around the lower connecting member 63. Note that FIG. 11, which will be described later, shows a state in which the end support members 61, 62 and the central support member 65 are rotated in the direction of the arrow A shown in FIG. 3.

[0037] The slide cylinder 66 shown in FIG. 4 slides the blade 24 in the width direction relative to the end support members 61, 62 and the central support member 65 by expanding and contracting. The slide cylinder 66 is arranged along the left-right direction. As shown in FIG. 7, the slide cylinder 66 has a cylinder portion 66a and a piston rod 66b. The cylinder portion 66a of the slide cylinder 66 is attached to the end support member 62. The tip of the piston rod 66b is attached to the rear surface side of the blade 24. The movement of the piston rod 66b relative to the cylinder portion 66a causes the blade 24 to move in the width direction of the blade 24 relative to the end support members 61, 62.

[0038] 7, the cover member 67 is disposed so as to cover the space between the support arm 53 and the central support member 65. The cover member 67 is supported by the upper connecting member 64 and the lower connecting member 63. The cover member 68 is disposed so as to cover the space between the central support member 65 and the support arm 54. The cover member 68 is supported by the upper connecting member 64 and the lower connecting member 63.

[0039] (Blade 24) 9 is a perspective view of the blade 24 as viewed from the rear. The blade 24 has a blade portion 91, a rear portion 92, a rail portion 93 (an example of a supported portion), a visor portion 94, and an end bit 95. The blade portion 91 is curved so as to protrude rearward. The blade portion 91 has an upper end portion 91a and a main body portion 91b. The upper end portion 91a is disposed above the main body portion 91b. The lower end of the main body portion 91b is shown as a cutting edge 91c (an example of the lower end of the blade).

[0040] The upper end portion 91a fits into the recessed portion 73a of the upper support portion 73 arranged on the upper protruding portion 72 of the end support member 61, the recessed portion 82a of the upper support portion 82 of the central support member 65, and the recessed portion 73a of the upper support portion 73 arranged on the upper protruding portion 72 of the end support member 62. The upper end portion 91a is fixed to the main body portion 91b. The upper end portion 91a may be removably attached to the main body portion 19b. It is more preferable that the upper end portion 91a is made of a material having higher wear resistance than the main body portion 91b, but they may be made of the same material.

[0041] The rear portion 92 is disposed on the rear surface 91d of the blade portion 91. As shown in FIG. 9, the rear portion 92 is disposed on the rear surface 91d along the width direction (left-right direction). The rear portion 92 is box-shaped. The rear portion 92 has an upper surface 92a, a lower surface 92b, a rear surface 92c, and a pair of side surfaces 92d. In a state in which the upper end portion 91a and the blade tip 91c are arranged vertically side by side as shown in FIG. 3, the upper surface 92a is disposed from the rear surface 91d toward the rear side. The upper surface 92a is inclined downward toward the rear. As a result, soil that has moved rearward beyond the upper end portion 91a of the blade 24 slides down the upper surface 92a and falls to the ground, so that soil can be prevented from accumulating on the upper surface 92a.

[0042] The state in which the upper end 91a and the cutting edge 91c are arranged vertically can also be said to mean that the upper end 91a and the cutting edge 91c are in the same position in the front-to-rear direction. In this specification, the term "vertical direction" does not have a strict meaning, but rather refers to a range that can be recognized as "vertical" in a socially acceptable sense, including a margin of error, and the term "same" does not have a strict meaning, but rather refers to a range that can be recognized as "same" in a socially acceptable sense, including a margin of error.

[0043] As shown in FIG. 3, the upper surface 92a is inclined so as to follow the upper end 91a from the rear side of the upper end 91a. In this specification, the inclination angle of the upper end 91a and the inclination angle of the upper surface 92a do not have to strictly match, and includes a range that can be recognized as following the upper end 91a from the rear side of the upper end 91a according to social convention. The lower surface 92b is disposed from the rear surface 91d toward the rear side in the state of the blade 24 shown in FIG. 3. The lower surface 92b is inclined so as to follow the rearward direction. The rear surface 92c connects the rear end of the upper surface 92a to the rear end of the lower surface 92b. The pair of side surfaces 92d connect both ends of the upper surface 92a, both ends of the lower surface 92b, and both ends of the rear surface 92c.

[0044] The rail portion 93 is disposed on the rear surface 92c as shown in FIG. 9. The rail portion 93 is a plate-shaped member. The rail portion 93 is disposed along the width direction. The rail portion 93 protrudes downward from the lower end of the rear surface 92c. The rail portion 93 fits into the recess 74a of the lower support portion 74 of the end support member 61 as shown in FIG. 3, and into the recess 74a of the lower support portion 74 of the end support member 62 as shown in FIG. 8. The upper end portion 91a fits into the upper support portion 82 and the pair of upper support portions 73, and the rail portion 93 fits into the pair of lower support portions 74, so that the blade 24 is supported by the rotating portion 41 by the upper support portion 82 and the pair of upper support portions 73, and the pair of lower support portions 74 so as to be slidable in the width direction. As shown in FIG. 3 and FIG. 8, the pair of lower support portions 74 support the blade 24 rearward and downward of the upper support portions 73 and 82. The upper support portion 82 and the pair of upper support portions 73 arranged on either side thereof correspond to an example of a first support portion. The pair of lower support portions 74 correspond to an example of a second support portion.

[0045] The eaves portion 94 is disposed on the upper surface 92a. The eaves portion 94 is a plate-shaped member. The eaves portion 94 is disposed along the width direction. The eaves portion 94 protrudes rearward from the rear end of the upper surface 92a. The eaves portion 94 is inclined downward as it approaches the rear. In the state shown in FIG. 3, the eaves portion 94 covers the upper side of the lower support portion 74. This makes it possible to prevent soil and sand sliding down from the upper surface 92a from entering the recessed portion 74a of the lower support portion 74. The end bits 95 are disposed on both ends of the blade portion 91 in the width direction, as shown in FIG. 6 and FIG. 9. The end bits 95 are disposed on the front surface of the blade portion 91.

[0046] As shown in FIG. 4, the tip of the piston rod 66b of the slide cylinder 66 described above is attached to the rear surface 92c of the rear portion 92.

[0047] As the slide cylinder 66 extends and retracts, the upper end portion 91a slides through the recess 82a and the pair of recesses 73a, and the rail portion 93 slides through the pair of recesses 74a, allowing the blade 24 to slide in the width direction (left and right direction) relative to the pair of end support members 61 and the central support member 65.

[0048] In this embodiment, the upper end 91a of the blade 24 is supported by the upper support portion 82 and a pair of upper support portions 73, so that there is no need to provide a slide rail on the upper part of the rear surface of the blade 24 as in the conventional method, and accumulation of soil and sand can be prevented.

[0049] (Positional relationship between the lift cylinder 34, the upper support portion 73, and the lower support portion 74) Next, the positional relationship between the lift cylinder 34, the upper support part 73, and the lower support part 74 will be described. Fig. 10 is a side view showing the draw bar 31, the blade 24, and the blade rotation support part 32. In Fig. 10, the blade 24 is in a state where the upper end part 91a and the cutting edge 91c of the blade 24 are aligned vertically. In this state, the blade 24 has rotated so that the upper end part 91a is positioned upward, and the bolt 75 is positioned near the front edge 71b of the through hole 71a.

[0050] As shown in FIG. 10, the tip of the piston rod 34b of the lift cylinder 34 is connected to the connection part 35 of the draw bar 31. The connection part 35, the positions of the upper support parts 73 and 82, and the position of the cutting edge 91c of the blade 24 are arranged on substantially the same vertical line in a side view (see line L1). Therefore, the extension of the lift cylinder 34 can efficiently press the cutting edge 91c of the blade 24 against the ground. In addition, since the connection part 35, the positions of the upper support parts 73 and 82, and the position of the cutting edge 91c of the blade 24 are arranged on a straight line, the blade 24 is less likely to shake, so that rattle is less likely to occur and wear is reduced. In addition, in this specification, "on a straight line" does not have a strict meaning, but includes errors and the like, and refers to a range that can be recognized as "on a straight line" according to social conventions.

[0051] FIG. 11 shows a state where the tilt cylinder 58 is extended from the state shown in FIG. 10 and the blade 24 is rotated so that the upper end 91a moves downward (see arrow A). In FIG. 11, the bolt 75 abuts against the rear edge 71c of the through hole 71a. As shown in FIG. 10 and FIG. 11, in this embodiment, the positions of the upper support parts 73, 82 are disposed at the same position as the connection part 35 in the front-rear direction or in front of the connection part 35. Also, as shown in FIG. 10 and FIG. 11, the lower support part 74 is disposed rearward of the connection part 35 in the front-rear direction. When the upper end 91a of the blade 24 is rotated so as to move downward, the positions of the upper support part 73 and the lower support part 74 are disposed on either side of a straight line L1 extending vertically from the connection part 35.

[0052] Furthermore, when the tilt cylinder 58 is in its most retracted state, as shown in Fig. 10, the upper support parts 73, 82 and the upper end part 91a of the blade 24 are disposed in a position overlapping with a line (straight line L1) extending downward from the connection part 35 in a side view. When the tilt cylinder 58 is extended from the state shown in Fig. 10, the upper support parts 73, 82 and the upper end part 91a of the blade 24 are disposed forward of the connection part 35 in the front-to-rear direction perpendicular to the straight line L1, as shown in Fig. 11. Fig. 11 shows the tilt cylinder 58 in its most extended state.

[0053] (Features, etc.) In the motor grader 1 of this embodiment, the support mechanism 23 has upper support parts 73, 82 that support the upper end part 91a of the blade 24, and a lower support part 74 that supports the blade 24 rearward and below the upper support parts 73, 82. This makes it possible to prevent soil and sand from accumulating without the need to provide a slide rail on the upper part of the rear surface of the blade 24 as in the conventional case.

[0054] In the motor grader 1 of this embodiment, the upper end 91a of the blade 24 fits into the upper support parts 73, 82 of the support mechanism 23, and the rail part 93 of the blade 24 fits into the lower support part 74. This allows the upper end 91a to slide on the upper support parts 73, 82 and the rail part 93 to slide on the lower support part 74, thereby allowing the blade 24 to slide relative to the support mechanism 23.

[0055] In the motor grader 1 of this embodiment, the upper support parts 73, 82 include recesses 73a, 82a, and an upper end part 91a of the blade 24 fits into the recesses 73a, 82a. The lower support part 74 includes a recess 74a, and a rail part 93 of the blade 24 fits into the recess 74a. This allows the upper end part 91a to slide within the recesses 73a, 82a, and the rail part 93 to slide within the recess 74a, thereby allowing the blade 24 to slide relative to the support mechanism 23.

[0056] In the motor grader 1 of this embodiment, the blade 24 has a blade portion 91 and a rear portion 92 disposed on a rear surface 91d of the blade portion 91. The rear portion 92 has an upper surface 92a that is inclined to follow the upper end portion 91a. This allows soil and sand to slide down the upper surface 92a and fall to the ground, even if the soil and sand moves over the upper end portion 91a of the blade 24 and moves toward the rear surface 91d of the blade portion 91, without accumulating on the rear portion 92.

[0057] The motor grader 1 of this embodiment has a eaves portion 94 that protrudes rearward from the upper surface 92a of the rear portion 92 of the blade 24. This makes it possible to prevent soil that has moved to the rear side of the blade 24 from falling into the recessed portion 74a of the lower support portion 74, etc.

[0058] In the motor grader 1 of this embodiment, when the cutting edge 91c and upper end 91a of the blade 24 are arranged vertically, the connection part 35 of the lift cylinder 34 to the drawbar 31 is arranged on a straight line L1 connecting the upper end 91a and the cutting edge. This allows the cutting edge 91c of the blade 24 to be efficiently pressed against the ground by extending the lift cylinder 34. In addition, by arranging the connection part 35, the positions of the upper supports 73, 82, and the position of the cutting edge 91c of the blade 24 on a straight line, the blade 24 is less likely to shake, making it less likely to rattle and reducing wear.

[0059] In the motor grader 1 of this embodiment, the upper end 91a of the blade 24 is disposed at the same position as or in front of the connection portion 35 in the front-to-rear direction. The lower support portion 74 is disposed rearward of the connection portion 35 in the front-to-rear direction. Therefore, when the upper end 91a of the blade 24 rotates so as to move downward, the positions of the upper support portions 73, 82 and the position of the lower support portion 74 are disposed on either side of a straight line L1 extending vertically from the connection portion 35.

[0060] The blade support structure of this embodiment includes upper support parts 73, 82 that support the upper end part 91a of the blade 24, and a lower support part 74 that supports the blade 24 rearward and below the upper support parts 73, 82. This makes it possible to prevent soil and sand from accumulating without the need to provide a slide rail on the upper part of the rear surface of the blade 24 as in the conventional case.

[0061] (Other embodiments) Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention.

[0062] (A) In the motor grader of the above embodiment, as shown in FIG. 3, the overhanging portion 94 covers the upper part of the lower support portion 74, but it may be extended further to cover the upper part of the slide cylinder 66.

[0063] (B) In the above embodiment, the upper end 91a of the blade 24 is supported by three members, namely, the end support members 61, 62 and the central support member 65, but this is not limited to this, and the upper end 91a of the blade 24 may be supported by two or less or four or more members.

[0064] (C) In the above embodiment, the rail portion 93 of the blade 24 is supported by two members, the end support members 61 and 62, but this is not limited to this, and the rail portion 93 of the blade 24 may be supported by one or three or more members.

[0065] (D) In the above embodiment, it has been described that the upper support portion 73 is attached to the upper protrusion 72, but the upper support portion 73 may be detachable from the upper protrusion 72. In this case, when the upper support portion 73 becomes worn, only the upper support portion 73 can be replaced. Furthermore, the upper protrusion 72 may be detachable from the main body portion 71. In this case, when the upper support portion 73 becomes worn, the upper protrusion 72 can be replaced together with the upper support portion 73. [Industrial Applicability]

[0066] The work vehicle and blade support structure disclosed herein can provide the effect of suppressing the accumulation of soil and sand. [Explanation of symbols]

[0067] 1: Motor grader 21: Front frame 22: Rear frame 23:Support mechanism 24: Blade 73: Upper support part 74: Lower support part 82: Upper support part 91a: Upper end

Claims

1. Rear frame and a front frame rotatably connected to the rear frame; Blade and a support mechanism that supports the blade on the front frame so as to be slidable along a width direction of the blade, The support mechanism includes a first support portion that supports an upper end portion of the blade, and a second support portion that supports the blade rearward and downward from the first support portion. Work vehicle.

2. The blade is A curved blade portion, a supported portion disposed on a rear side of the blade portion along the width direction, The upper end of the blade is fitted into the first support portion, The supported portion of the blade is fitted into the second support portion. A work vehicle according to claim 1.

3. The support mechanism includes: a drawbar connected to the front frame so as to be capable of swinging up and down; A lift cylinder that swings the draw bar up and down; a rotating portion rotatably supported by the drawbar; a blade support portion having the first support portion and the second support portion, the blade support portion being supported on the rotating portion so as to be swingable in the front-rear direction and supporting the blade; having The blade support portion is The blade further includes a plurality of support members arranged side by side in the width direction and supporting the blade on the rotating portion, the first support portion is formed in each of the plurality of support members and includes a first recess into which the upper end of the blade is fitted; The second support portion is formed in each of the plurality of support members and includes a second recess into which the supported portion of the blade fits. The work vehicle according to claim 2.

4. The blade is A curved blade portion, a rear portion disposed on a rear surface of the blade portion, The rear portion has an upper surface that is inclined to conform to the upper end portion. A work vehicle according to claim 1.

5. The blade is A curved blade portion, a rear portion disposed on a rear surface of the blade portion; and a visor portion protruding rearward from an upper surface of the rear portion. A work vehicle according to claim 1.

6. The support mechanism includes: a drawbar connected to the front frame so as to be capable of swinging up and down; A lift cylinder that swings the draw bar up and down; a blade rotation support portion that rotatably supports the blade on the draw bar, When viewed from the side, the upper end of the blade is disposed at a position overlapping a line extending downward from a connection portion of the lift cylinder to the draw bar or is disposed forward of the connection portion in the front-rear direction. A work vehicle according to claim 1.

7. The support mechanism includes: a drawbar connected to the front frame so as to be capable of swinging up and down; A lift cylinder that swings the draw bar up and down; a blade rotation support portion that rotatably supports the blade on the draw bar, When viewed from the side, in a state in which the lower end and the upper end of the blade are arranged in a vertical direction, a connection portion of the lift cylinder to the draw bar is arranged on a straight line connecting the first support portion and the lower end. A work vehicle according to claim 1.

8. In the front-rear direction, the second support portion is disposed rearward of the connection portion. A work vehicle according to claim 6.

9. A blade support structure for a motor grader having a rear frame and a front frame rotatably connected to the rear frame, the blade support structure supporting the blade on the front frame slidably along a width direction of the blade, A first support portion that supports an upper end portion of the blade; A second support portion that supports the blade rearward and downward from the first support portion. Blade support structure.

10. Rear frame and a front frame rotatably connected to the rear frame; Blade and a support mechanism that supports the blade on the front frame so as to be slidable along a width direction of the blade, The support mechanism includes: a drawbar connected to the front frame so as to be capable of swinging up and down; A lift cylinder that swings the draw bar up and down; a blade rotation support portion that rotatably supports the blade on the draw bar, When viewed from the side, an upper end of the blade is disposed at a position overlapping a line extending downward from a connection portion of the lift cylinder to the draw bar or is disposed forward of the connection portion in the front-rear direction. Work vehicle.

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