JP2013086715A - Work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work vehicle capable of keeping an operator's riding comfort when the operator sits down in a driving seat.SOLUTION: The work vehicle includes a traveling machine body 11 which is equipped with an engine 8, and a track frame 17 which is provided in the lower part of the traveling machine body 11 and which winds and supports a traveling crawler 25. The track frame 17 is attached in a forward and backward swingable manner to the traveling machine body 11 via a link mechanism. The link mechanism comprises a pair of front and rear link members 19 and 20. The traveling machine body 11, the pair of front and rear link members 19 and 20, and the track frame 17 configure a four-link structure.

Description

  The present invention relates to a work vehicle such as a tractor in which left and right traveling crawlers are installed at the rear of a traveling machine body on which an engine and the like are mounted.

  The left and right traveling crawlers are installed at the rear part of the traveling machine body in a work vehicle such as a tractor, that is, the left and right front wheels are installed at the front part of the traveling machine body, and the left and right traveling crawlers are installed at the rear part of the traveling machine body. This is described in Patent Documents 1 to 3 as prior art.

  In the prior art, a rear axle is pivotally supported on a rear axle case of a traveling machine body, and a driving wheel body is attached to the rear axle, while a track frame extending in the front-rear direction is disposed at a portion below the rear axle case. The track frame is mounted with a traveling crawler, and a substantially middle portion in the front-rear direction of the track frame is disposed on the traveling machine body side of the rear axle case or the like at a position below the rear axle by an appropriate distance. The single swing fulcrum shaft is pivotally attached to the track frame so that the front and rear portions of the track frame move up and down in opposite directions. A traveling crawler is wound in a substantially triangular shape across the front driven wheel provided on the front end side of the track frame, the rear driven wheel provided on the rear end side, and the drive wheel. By rotating the traveling crawler, the traveling machine body is moved forward or backward.

Japanese Patent Laid-Open No. 10-45051 JP 2006-96199 A JP 2004-217054 A

  In the prior art, when the front part of the traveling machine body is pitched so as to move up and down, the traveling crawler that is in contact with the ground is inclined upward or downward about the swing fulcrum shaft. Therefore, there are problems as described below. For example, when moving forward or backward, when traveling over a convex part such as a farm shore, the traveling crawler tilts forward or downward about the swing fulcrum shaft, and the grounding surface of the traveling crawler Since the inclination angle in the front-rear direction tends to be large, the ground height of the traveling aircraft body is likely to change, and there is a problem that a good ride comfort of the operator who has boarded the control seat cannot be maintained. In addition, since the track frame is supported by the swing fulcrum shaft at a single point, the load is concentrated on the swing fulcrum shaft part, which not only prevents an increase in size, but also the swing frame. There is also a problem that a malfunction may occur due to deformation or the like of the moving fulcrum shaft.

  The present invention seeks to provide a work vehicle such as a tractor that has been improved by examining these current conditions.

  According to a first aspect of the present invention, there is provided a traveling machine body on which an engine is mounted, and a track frame that is provided at a lower portion of the traveling machine body and supports a traveling crawler around the traveling machine body. A work vehicle in which a frame is attached so as to be swingable back and forth, wherein the link mechanism is constituted by a pair of front and rear link members, and the traveling machine body, the pair of front and rear link members, and the track frame have a four-bar link structure. There is nothing.

  According to a second aspect of the present invention, in the work vehicle according to the first aspect, the outer periphery of the driving wheel body is provided with a plurality of metal cores at equal intervals on the inner peripheral side of the traveling crawler and drives the traveling crawler to rotate. A locking tooth body that engages with the metal core, and a ring-shaped portion; a rubber belt body is provided on the inner peripheral side of the traveling crawler; and the ring-shaped portion of the drive wheel body The advancing crawler is configured to rotate around by contacting the rubber belt body.

  According to a third aspect of the present invention, in the work vehicle according to the first or second aspect, the track frame includes a driven wheel body around which the traveling crawler is wound, and further supports the driven wheel body. An idler fork that can be expanded and contracted, and a tension spring that biases the driven wheel body on the inner peripheral side of the traveling crawler.

  According to the first aspect of the present invention, the vehicle includes a traveling machine body on which an engine is mounted, and a track frame that is provided at a lower portion of the traveling machine body and supports a traveling crawler around the traveling vehicle body, and the traveling machine body includes the link frame via a link mechanism. A work vehicle in which a track frame is attached so as to be swingable back and forth, wherein the link mechanism is constituted by a pair of front and rear link members, and the traveling machine body, the pair of front and rear link members, and the track frame have a four-bar link structure Therefore, the presence of the four-bar link structure makes it possible to support the traveling machine body, for example, by separating it from a ridge or a tall crop in a work vehicle straddling work. Sufficient space can be secured for crops. In addition, it is possible to prevent the traveling crawler from tilting forward and backward with a parallel link approximating operation of the four-bar link structure while ensuring a sufficient space for a ridge or a tall crop. . In addition, it is possible to prevent a significant variation in the ground resistance of the traveling crawler, and to reduce the risk of field disturbance and meandering.

  According to the second aspect of the present invention, a plurality of metal cores are provided at equal intervals on the inner peripheral side of the traveling crawler, and the outer peripheral side of the driving wheel body that drives the traveling crawler to rotate is engaged with the metal core. The engaging tooth body and the ring-shaped portion are combined, a rubber belt body is provided on the inner peripheral side of the traveling crawler, and the ring-shaped portion of the driving wheel body comes into contact with the rubber belt body, Since the traveling crawler is configured to rotate around, not only the engagement tooth body of the driving wheel body and the metal core of the traveling crawler are engaged, but also the ring-shaped portion of the driving wheel body. Also, the rotational force of the driving wheel can be transmitted to the traveling crawler by friction driving between the driving belt and the rubber belt. Therefore, it is possible to reduce the metal contact noise due to the engagement between the locking tooth body of the driving wheel body and the core metal body of the traveling crawler. That is, the driving noise of the traveling crawler can be reduced.

  According to the invention of claim 3, the track frame includes a driven wheel body around which the traveling crawler is wound, and further includes an extendable idler fork that supports the driven wheel body, and the traveling crawler. Since the tension spring for biasing the driven wheel body is provided on the inner peripheral side, the tension of the traveling crawler can be adjusted and maintained by a simple tension adjusting structure provided with, for example, a tension bolt.

It is a side view of the tractor which shows the embodiment of the present invention. It is the same top view. It is a side enlarged view of a crawler traveling device. It is a side view of a track frame part. It is a disassembled perspective view of the crawler traveling device in the right rear view. It is a disassembled perspective view of the crawler traveling device in the left rear view. It is a disassembled perspective view of the right rear view of a track frame support part. It is a disassembled perspective view of the left side view of a track frame support part. It is a cross-sectional explanatory drawing of the back view of a crawler traveling apparatus. It is sectional explanatory drawing of the back view of a track frame support part. It is an expanded sectional view of a track frame support part. It is decomposition | disassembly explanatory drawing of FIG. It is expansion explanatory drawing of the rear view of a rolling wheel part. It is an expanded sectional view of a driving wheel body part in the back view. It is a partial expanded explanatory view of a driving wheel body part. It is a fragmentary perspective view of a driving wheel body part. It is decomposition | disassembly explanatory drawing of a driving wheel body part. It is a partial expanded explanatory view of a traveling crawler and a driving wheel body part. It is a principal part expanded explanatory view which shows the attachment modification of a drive wheel body part. It is a partial expanded sectional view of a traveling crawler. It is principal part expansion explanatory drawing which shows the modification of a driving | running | working crawler. It is a principal part enlarged explanatory view which shows the modification of a drive wheel body part. It is principal part expansion explanatory drawing which shows the modification of a driving | running | working crawler and a driving wheel body part. It is principal part expansion explanatory drawing which shows the modification of a driving | running | working crawler and a rolling wheel part. It is principal part explanatory drawing which shows the connection structure of the partial ring body in a drive wheel body. It is principal part explanatory drawing which shows arrangement | positioning of a driving | running | working crawler and a driving wheel body. It is principal part expansion explanatory drawing which shows the bearing structure of a rolling wheel part. It is principal part expansion explanatory drawing which shows the modification of the bearing structure of a rolling wheel part. It is principal part expansion explanatory drawing which shows the modification of the bearing structure of a rolling wheel part. It is principal part expansion explanatory drawing which shows the bearing structure of a driven wheel part. It is a principal part cross-sectional side view which shows the tension structure of a front driven wheel. It is a principal part cross-sectional rear view which shows the tension structure of a front driven wheel. It is action | operation explanatory drawing of FIG. It is principal part cross-section explanatory drawing which shows the modification of the tension structure of a front driven wheel. It is principal part cross-section explanatory drawing which shows the modification of the tension structure of a front driven wheel. It is principal part cross-section explanatory drawing which shows the modification of the tension structure of a front driven wheel. It is explanatory drawing of a crawler guide body, (a) is a top view, (b) is a front view, (c) is a bottom view, (d) is a left side view, (e) is a right side view, (f) is a side view (B) ff sectional drawing, (g) is the perspective view seen from diagonally upward. It is a partially cutaway side view of a track frame part. It is an enlarged plan view which shows the positional relationship of a driven wheel body and a crawler guide body. It is cross-sectional explanatory drawing of the back view which shows the traveling crawler of a standard specification. It is a cross-sectional explanatory drawing of the back view which shows the traveling crawler of offset specification. It is cross-sectional explanatory drawing of the back view which shows the traveling crawler of a narrow specification. It is a figure explaining the other example of the front and rear link member, (a) is a schematic side view, (b) is a cross-sectional explanatory drawing of back view.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings when applied to a tractor. As shown in FIGS. 1-4, the code | symbol 10 in a figure shows a tractor. The tractor 10 includes a traveling machine body 11, a pair of left and right front wheels 12 that support the front part of the traveling machine body 11, and a pair of left and right rear crawler traveling devices 13 that support the rear part of the traveling machine body 11. The traveling body 11 is equipped with an engine 8 and a control seat 9.

  As shown in FIGS. 1 to 4, a transmission case 40 is mounted on the rear part of the traveling machine body 11. Left and right rear axle cases 14 are provided on both left and right sides of the mission case 40. A rear crawler traveling device 13 is detachably attached to the traveling machine body 11 via a rear axle case 14. As shown in FIG. 9, one end of the rear axle 15 is pivotally supported in the rear axle case 14, and then a reduction final gear 37 is pivotally supported on one end of the axle 15. The other end side of the rear axle 15 is protruded from the rear axle case 14, and then the driving wheel body 16 is attached to the other end side of the axle 15. On the other hand, a track frame 17 extending in the front-rear direction is disposed below the rear axle case 14. A flange member 18 is detachably fastened to the rear axle case 14. A front link member 19 disposed on the front side of the rear axle 15 and a rear link member 20 disposed on the rear side of the rear axle 15 are provided. The track frame 17 is connected to the flange member 18 via the link members 19 and 20 so as to be swingable back and forth. That is, the flange member 18 (also referred to as the traveling machine body 11), the pair of front and rear link members 19 and 20, and the track frame 17 form a four-bar link structure.

  As shown in FIGS. 1 to 4, a front driven wheel body 21 is attached to the front end side of the track frame 17 via a tension adjusting mechanism 22. A rear driven wheel body 23 is attached to the rear end side of the track frame 17 by a support shaft 24. Synthetic rubber traveling crawlers 25 serving as crawler belts are wound around the drive wheel body 16, the front driven wheel body 21, and the rear driven wheel body 23 in a substantially triangular shape. The driving wheel body 16 (rear axle 15) is rotated forward or backward at an appropriate speed and the traveling crawler 25 is driven forward or backward to drive the traveling machine body 11 forward or backward. ing.

  A plurality of rolling wheels 26 and a crawler guide body 41 are provided. The plurality of rolling wheels 26 are rotatably provided on the track frame 17. Three rolling wheels 26 of the embodiment are arranged side by side. The crawler guide body 41 is for preventing the traveling crawler 25 from coming off in the left-right direction, and for holding down a plurality of metal cores 95 (see FIGS. 18 and 20) embedded in the traveling crawler 25 at equal intervals. Yes, and fastened to the track frame 17. A plurality of rolling wheels 26 and a crawler guide are arranged on an inner peripheral surface (an inner peripheral surface on the grounding side of the traveling crawler 25) between the front driven wheel body 21 and the rear driven wheel body 23 among the inner peripheral surface of the traveling crawler 25. The body 41 is brought into contact. The crawler guide body 41 is formed in a boat shape having an inverted T shape when viewed from the side. The plurality of rolling wheels 26 and the crawler guide body 41 are configured to land and support the grounding side of the traveling crawler 25.

  As shown in FIGS. 3 and 4, front and rear upper pivot shafts 27 and 28 are provided on the flange member 18. Front and rear upper end pivot shafts 27 and 28 are extended in parallel with the rear axle 15. The upper end side boss portions of the front link member 19 and the rear link member 20 are rotatably supported by the front and rear upper end pivot shafts 27 and 28. The track frame 17 is provided with front and rear lower pivot shafts 30 and 31. The lower end of the front link member 19 is rotatably connected to the track frame 17 by a front lower end pivot shaft 30. The front lower end pivot shaft 30 is positioned on the front side of the front upper pivot shaft 27, and the front link member 19 is tilted forward and supported.

  As shown in FIGS. 3 and 4, the rear link member 20 has a lower end rotatably connected to the track frame 17 by a rear lower end pivot shaft 31. The rear lower end pivot shaft 31 is positioned rearward of the rear upper pivot shaft 28, and the rear link member 20 is tilted backward and supported. As a result, the front and rear link members 19 and 20 are arranged in a C shape spreading downward from each other in a side view of the tractor 10 (FIGS. 3 and 4). The traveling crawler 25 has a distance Df from the vertical line passing through the rear axle 15 to the front driven wheel body 21 in the side view of the tractor 10 (FIGS. 3 and 4). It is stretched in a substantially triangular shape larger than the distance Db to 23.

  With the above configuration, when the tractor 10 is caused to travel forward, the traveling crawler 25 receives the forward reaction force from the ground, whereby the track frame 17 moves forward with respect to the traveling machine body 11 and the traveling crawler 25 rises forward. Inclined to posture. That is, when the track frame 17 moves in the forward direction with respect to the traveling machine body 11, the front link member 19 is rotated in the direction in which the front link member 19 is tilted so that the inclination angle from the horizontal plane becomes small with the upper pivot shaft 27 as a fulcrum. Move. Further, the rear link member 20 rotates in the direction in which the rear link member 20 stands up so that the inclination angle from the horizontal plane becomes larger with the upper end pivot shaft 28 as a fulcrum. As a result, the traveling crawler 25 tilts forward and moves forward.

  On the other hand, when the tractor 10 is caused to travel backward, by receiving a reverse reaction force from the ground, the track frame 17 moves rearward with respect to the traveling machine body 11, and the traveling crawler 25 is inclined to the forward lowering posture. That is, when the track frame 17 moves rearward with respect to the traveling machine body 11, the front link member 19 stands up so that the inclination angle from the horizontal plane increases with the front upper end pivot shaft 27 as a fulcrum. To turn. Further, the rear link member 20 is rotated in a direction in which the rear link member 20 is tilted so that the inclination angle from the horizontal plane becomes small with the rear upper end pivot shaft 28 as a fulcrum. As a result, the traveling crawler 25 tilts forward and moves backward.

  When the driving of the traveling crawler 25 inside the turn is interrupted to turn left or right, the traveling crawler 25 inside the turning tilts forward and downward during forward traveling, and during backward traveling. The traveling crawler 25 on the inner side of the turn is inclined upward.

  Front and rear restricting pins as stoppers for restricting forward rotation of the front link member 19 with the front upper end pivot shaft 27 as a fulcrum and rear rotation of the rear link member 20 with the rear upper end pivot shaft 28 as a fulcrum. 34, 34 a, 35, 35 a are provided on the flange member 18. A range in which the lower end side of the front link member 19 (rear link member 20) rotates forward with the front upper end pivot shaft 27 as a fulcrum is set by the front restriction pin 34 (front restriction pin 34a). A range in which the lower end side of the rear link member 20 (front link member 19) rotates backward with the rear upper end pivot shaft 28 as a fulcrum is set by the rear restriction pin 35 (rear restriction pin 35a). The forward and backward movement of the traveling crawler 25 relative to the traveling machine body 11 is configured to be restricted by the front and rear restricting pins 34, 34a, 35, and 35a.

  And when it pitches so that the front part of the said traveling body 11 may fall (forward inclination operation | movement), the front link member 19 will be in the direction which falls so that the inclination angle from a horizontal surface may become small with the front-lower-end pivot shaft 30 as a fulcrum. Rotate. On the other hand, the rear link member 20 rotates with respect to the track frame 17 so as to stand up so that the inclination angle from the horizontal plane becomes larger with the rear lower end pivot shaft 31 as a fulcrum. Accordingly, the traveling crawler 25 is supported in a forwardly raised posture with respect to the traveling machine body 11.

  Further, when pitching (backward tilting operation) so that the front portion of the traveling machine body 11 is raised, the front link member 19 stands up so that the inclination angle from the horizontal plane becomes larger with the front lower end pivot shaft 30 as a fulcrum. To turn. On the other hand, the rear link member 20 rotates in the direction of falling so that the inclination angle from the horizontal plane becomes smaller with the rear lower end pivot shaft 31 as a fulcrum. As a result, the traveling crawler 25 is supported in the forwardly lowered posture with respect to the traveling machine body 11.

  By the way, in the four-bar link structure constituted by the flange member 18, the pair of front and rear link members 19 and 20, and the track frame 17, the “instant center” when the track frame 17 as one node moves in the longitudinal direction. "Is located at the intersection where the extension line of the front link member 19 and the extension line of the rear link member 20 cross each other. The track frame 17 moves in the longitudinal direction around the “instantaneous center”.

  In this case, the front and rear link members 19 and 20 are arranged in a downwardly widened C shape, so that the instantaneous center moves to the rear side of the aircraft when the traveling vehicle 11 is pitched forward and downward. When the traveling machine body 11 is pitched forwardly, it moves to the front side of the machine body, so that the instantaneous center can be held at a height that approximates the height of the rear axle 15. As a result, when the traveling machine body 11 pitches, the distance that the traveling machine body 11 moves back and forth with respect to the track frame 17 can be significantly reduced compared to the longitudinal movement distance of the prior art.

  Further, as shown in FIGS. 1 and 2, a rotary tiller working machine 1 having a rotary tiller 2 is provided. The lower link 3 and the top link 4 (three-point link mechanism) protrude from the rear part of the traveling machine body 11 to the rear side, and the rotary tiller 1 is mounted on the lower link 3 and the top link 4. A hydraulic lift mechanism 5 is provided at the rear part of the traveling machine body 11 (upper part of the transmission case 40). A front and rear intermediate portion of the lower link 3 is connected to a lift arm 6 of the hydraulic lift mechanism 5 via a lift rod 7. While the rotary tiller 1 is moved up and down by operation of the hydraulic lift mechanism 5, the rotary tillage claws 2 are used to cultivate the soil in the field. Needless to say, various working machines can be attached to the tractor 10 instead of the rotary tilling work machine 1.

  Next, with reference to FIGS. 5 to 10, the mounting structure of the track frame 17, the link members 19 and 20, and the flange member 18 will be described. As shown in FIGS. 8 to 10, the flange member 18 is made of a steel plate and a flat plate-shaped first bracket body 51, a steel plate and a flat plate-shaped second bracket body 52, and a steel plate and a flat plate-shaped third bracket before and after the flat plate shape. There are bracket bodies 53, 54, and horizontal rail-shaped bracket bodies 55, 56, 57 in the front and rear of a flat plate shape made of a steel plate. The first bracket body 51 and the second bracket body 52 are formed in the same shape. The front and rear horizontal rail bracket bodies 55 and 56 are fixed to the front and rear third bracket bodies 53 and 54 by welding.

  Then, bolts 61 are fastened to the first bracket body 51 and the second bracket body 52 in a cantilever manner at one end side of the two front and rear restriction pins 34 and 35 on the large diameter side. The other end sides of the restricting pins 34 and 35 are projected from the opposing surfaces of the first bracket body 51 and the second bracket body 52. Furthermore, the bolts 62 are fastened to the first bracket body 51 and the second bracket body 52 in the form of both ends at both end surfaces of the front and rear horizontal cross-bar bracket bodies 55, 56, 57. Also, the nuts 63 are fastened to the first bracket body 51 and the second bracket body 52 in the form of both ends with the screw portions at both ends of the two front and rear restricting pins 34a and 35a on the small diameter side.

  In addition, the front and rear upper end pivot shafts 27 and 28 are passed through the upper end boss portions of the front and rear link members 19 and 20, and both end portions of the front and rear upper pivot shafts 27 and 28 are connected to the first bracket body 51. And the bolt 65 is fastened to the 2nd bracket body 52 via the shaft pressing plate body 64 in the both-ends form. The shaft retainer plate 64 is fastened with a nut 63 to prevent the shaft retainer plate 64 from rotating about its axis.

  Meanwhile, the seat plate body 66 is fixed to the first bracket body 51 by welding. The first bracket body 51 and the seat plate body 66 are fastened to the rear axle case 14 with bolts 67 and 68, respectively. Further, the front and rear third bracket bodies 53 and 54 are fastened to the rear axle case 14 with bolts 69 and 70, respectively. The rear axle case 14 is detachably fixed between the first bracket body 51 and the third bracket bodies 53 and 54 in a sandwiched manner. In the assembling operation, the second bracket body 52 is fixed to the first bracket body 51 and the front and rear link members 19 and 20 are provided on the flange member 18 to constitute a unit. After that, the flange member 18 of the unit structure is brought into contact with the bottom surface side of the rear axle case 14 from the lower side of the rear axle case 14, and the first bracket body 51, the seat plate body 66, and the third bracket bodies 53 and 54. The bolts 67, 68, 69, 70 are fastened, and the front and rear link members 19, 20 are assembled to the rear axle case 14 via the flange member 18.

  Further, the steady bracket body 44 is fixed to the seat plate body 66 by welding. The left and right turnbuckle check chain body 45 as a stabilizer is mounted so that the tilling work machine 1 (left and right lower links 3) does not swing to the left and right more than necessary in a state where the swinging work machine 1 allows a slight swing in the left and right direction. Provide. One end side of the check chain body 45 is connected to the middle of the front and rear width of the lower link 3, and the other end side of the check chain body 45 is detachably connected to the steady bracket body 44.

  Next, referring to FIGS. 4 and 9 to 13, a connection structure between the track frame 17 and the link members 19 and 20 will be described. As shown in FIGS. 11 and 12, the body inner shaft portion 76 on one end side of the lower pivot shafts 30 and 31 is rotated on the lower boss portion of the link members 19 and 20 via slide bearing metals 71 and 72. It is pivotally supported. A large-diameter shaft portion 73 and a taper-shaped tape are formed on the other end side (outside the fuselage) of the lower pivot shafts 30 and 31 that protrude from the lower boss side of the link members 19 and 20 toward the outer side of the fuselage. A pad portion 74 and a small diameter shaft portion 75 are provided. A small-diameter shaft portion 75 is connected to the large-diameter shaft portion 73 via a taper portion 74. Bolt holes 76 are formed in the end surfaces on the other end side of the lower end pivot shafts 30 and 31. In addition, the outer diameter of the body inner shaft portion 76 is formed larger than the outer diameter of the large diameter shaft portion 73.

  As shown in FIGS. 11 and 12, a bearing cylinder 77 is welded and fixed to the upper surface of a square columnar track frame 17 elongated in the front-rear direction. The large diameter hole 78 for inserting the large diameter shaft portion 73 of the lower end pivot shafts 30 and 31, the small diameter hole 79 for inserting the small diameter shaft portion 75 of the lower end pivot shafts 30 and 31, and the small diameter hole 79 are large. A shaft hole 81 of the bearing cylinder 77 is formed by a taper hole 80 communicating with the diameter hole 78. A thrust washer 82 is fitted on the other end side (outside the machine body) of the lower pivot shafts 30 and 31, and a bearing cylinder 77 is fitted.

  With the above configuration, the other end side of the lower pivot shafts 30 and 31 projecting from the lower boss portions of the link members 19 and 20 with the small diameter shaft portion 75 as the head in the shaft hole 81 from the large diameter hole 78 side. To insert. The shaft retainer plate 64 is brought into contact with the end surface of the bearing cylinder 77 on the small diameter hole 79 side, the tip of the bolt 65 is inserted into the small diameter hole 79, and the bolt 65 is inserted into the bolt hole 76 on the bottom end pivot shaft 30, 31 end surface. The small-diameter shaft portion 75 is press-fitted into the small-diameter hole 79, the large-diameter shaft portion 73 is press-fitted into the large-diameter hole 78, and the lower pivot shafts 30, 31 are inserted into the bearing cylinder 77 on the top surface of the track frame 17. Secure the other end.

  As shown in FIGS. 1, 4, and 9 to 13, a traveling machine body 11 on which the engine 8 is mounted, left and right front wheels 12 that are provided below the front part of the traveling machine body 11, and a lower rear part of the traveling machine body 11. A track frame 17 and left and right traveling crawlers 25 attached to the track frame 17, a rear axle 15 that transmits rotational force to the traveling crawler 25, and a swing that supports the track frame 17 on the traveling body 11 so as to be swingable. In a working vehicle in which the front and rear upper pivot shafts 27 and 28 as fulcrum shafts are provided apart from each other, the front and rear upper pivot shafts 27 are directly below the rear axle case 14 as an axle case on which the rear axle 15 is pivotally supported. , 28, and the track frame 17 is connected to the rear axle case 14 via the front link member 19 and the rear link member 20 provided on the front and rear upper pivot shafts 27, 28. Therefore, for example, when moving forward or backward, when traveling over a convex portion such as a farm shore, the traveling crawler 25 tilts forward or downward with the front and rear upper pivot shafts 27 and 28 as the center. However, the inclination angle in the front-rear direction of the ground contact surface of the traveling crawler 25 is smaller than that of the conventional art. That is, the ground height of the traveling machine body 11 is less likely to change than before, and the ride comfort of the operator who has boarded the control seat 9 can be maintained in a good state.

  As shown in FIGS. 4 and 9 to 13, the front and rear upper pivot shafts 27 and 28 and the front and lower lower pivot shafts 30 and 31 form a swing fulcrum shaft, and the rear axle case 14 has the front and rear upper pivots. Attaching shafts 27 and 28 are provided, front and rear lower end pivoting shafts 30 and 31 are provided on the track frame 17, and upper and lower end portions of the front and rear link members 20 and 21 are provided on the respective pivoting shafts 27, 28, 30, and 31. It is connected. Therefore, even if the support load to the traveling machine body 11 of the track frame 17 is large, the support loads on the front and rear upper pivot shafts 27 and 28 and the front and lower lower pivot shafts 30 and 31 can be reduced. Can be easily achieved. Further, it is possible to reduce the occurrence of malfunction due to deformation of the pivot shafts 27, 28, 30, 31 and the like, and to improve the load resistance or durability.

  As shown in FIGS. 9 to 13, a first bracket body 51 as an inboard fulcrum body and a second bracket body 52 as an outboard fulcrum body are provided on the inboard side surface and the outboard side surface of the rear axle case 14. Components of the lower link 3 as a link mechanism for supporting the tilling work machine 1 on the traveling machine body 11 by sandwiching the front and rear upper pivot shafts 27 and 28 between the bracket body 51 and the second bracket body 52 ( The front and rear upper pivot shafts 27 and 28 or the front and rear link members 19 and 20 are arranged on the outer side of the check chain body 45). Accordingly, the support rigidity of the upper end pivot shafts 27 and 28 can be easily improved while the lower link 3 can be moved up and down without being limited by the rear upper end pivot shaft 28 or the rear link members 19 and 20. . Further, the support structure for the upper pivot shafts 27 and 28 can be simplified, and the manufacturing cost can be reduced.

  As shown in FIG. 10, the front and rear lower pivot shafts 30 and 31 are provided on the track frame 17 within the lateral width of the traveling crawler 25, and the lower ends of the front and rear link members 19 and 20 are offset to the track frame 17 side. It is configured. Therefore, the lower end pivoting shafts 30 and 31 or the link members 19 and 20 can be installed without substantially projecting the lower end pivotal shafts 30 and 31 or the link members 19 and 20 from the left and right widths of the traveling crawler 25. Therefore, for example, the front and rear lower pivot shafts 30 and 31 or the front and rear link members 19 and 20 can be supported while being separated from the heel G or the tall crop in the tractor 10 crossing ridge, and the heel G or the tall crop is supported. Sufficient space can be secured.

  As shown in FIGS. 1, 4, and 11, a traveling machine body 11 on which the engine 8 is mounted, left and right front wheels 12 provided on the lower front side of the traveling machine body 11, and a track frame 17 provided on the lower rear side of the traveling machine body 11. The left and right traveling crawlers 25 attached to the track frame 17, the rear axle 15 for transmitting the rotational force to the traveling crawler 25, and a plurality of rolling wheels 26 provided on the track frame 17, via the plurality of rolling wheels 26. In the work vehicle that supports the grounding side of the traveling crawler 25, the front upper end pivot shaft 27 and the rear upper end pivot shaft 28 as the two upper pivot shafts provided immediately below the rear axle 15, and the track frame 17 Two link members 19 and 20 are connected between a front lower pivot shaft 30 and a rear lower pivot shaft 31 as two lower pivot shafts provided, and two link members 19 and 20 are connected to the front and rear of the rear axle 15. Top front upper pivot 27 and the rear upper end pivot shaft 28 are arranged in a distributed manner, and two lower front pivot shafts 30 and rear lower pivot shafts 31 are disposed on the upper surface side between the plurality of rolling wheels 26 on the upper surface side of the track frame 17. One of the is arranged. Therefore, the support height of the front lower end pivot shaft 30 provided between the plurality of rolling wheels 26 can be lowered. While the bearing structure of the upper and lower front upper pivot shafts 27 and the front lower pivot shaft 30 can be reduced in cost or weight, the bearing of the front lower pivot shaft 30 against the ground reaction force of the traveling crawler 25. The structure can be advantageously constructed in terms of strength. Further, the length of the boss body of the link member 19 can be easily secured, and the boss body of the front link member 19 can be pivotally supported on the front lower end pivot shaft 30 by using a highly versatile bush.

  As shown in FIGS. 4 and 11, the track frame 17 supports the rear grounding side of the traveling crawler 25 via the rear driven wheel body 23, and includes the rolling wheel 26 adjacent to the rear driven wheel body 23 and the rear driven wheel body 23. Between the moving wheel bodies 23, the other of the two front lower pivot shafts 30 and the rear lower pivot shaft 31 is disposed on the upper surface side of the track frame 17. Therefore, the support height of the rear lower end pivot shaft 31 provided between the rolling wheel 26 adjacent to the rear driven wheel body 23 and the rear driven wheel body 23 can be reduced. With respect to the ground reaction force of the traveling crawler 25, the bearing structure of the rear lower end pivot shaft 31 can be advantageously configured in terms of strength. Moreover, the boss body length of the link members 19 and 20 can be ensured easily, and the boss body of the rear link member 20 can be pivotally supported on the rear lower end pivot shaft 31 by using a versatile bush.

  As shown in FIG. 4, the two link members 19 and 20 are arranged in a letter C shape in a side view of the body, and the two link members 19 are more than the distance between the upper ends of the two link members 19 and 20. , 20 is configured such that the distance between the lower end sides thereof is increased. Therefore, compared with the conventional single fulcrum structure, the allowance of the two link members 19 and 20 projected from the traveling crawler 25 toward the traveling machine body 11 can be reduced. When the 20 member swings, it is possible to easily reduce the occurrence of problems such as the mud adhering to the two link members 19 and 20 interfering with surrounding components.

  As shown in FIGS. 4 and 11, a front upper end pivot shaft 27 and a rear upper end pivot shaft 28 are disposed in the vicinity of the driving resultant force line X on the forward side of the traveling crawler 25, and the pivot shaft 27 on the front side of the machine body is disposed. It is arranged below the driving resultant line X so that the center Y of the swing locus of the track frame 17 is below the driving resultant line X. Therefore, the link members 19 and 20 can be supported so as not to be easily displaced with respect to the driving force on the forward side of the traveling crawler 25, and the traveling crawler 25 can follow the road surface against the rolling reaction force. When starting or stopping, the traveling machine body 11 can be prevented from tilting back and forth, and the traveling machine body 11 can be moved in a stable posture.

  As shown in FIGS. 11 and 12, a front lower end pivot shaft 30 and a rear lower pivot shaft 31 are formed in a two-stage stepped shaft shape, and a bearing cylinder 77 as a lower bearing body provided in the track frame 17 is formed. The bolt 65 is fastened, so that the front lower end pivot shaft 30 and the rear lower pivot shaft 31 have two stepped shaft portions (a large diameter shaft portion 73 of the lower end pivot shaft and a small diameter shaft portion 75 of the lower end pivot shaft). Are configured to be press-fitted. Therefore, the front lower end pivot shaft 30 and the rear lower pivot shaft 31 are tapered and the front lower pivot shaft 30 and the rear lower pivot shaft 31 are assembled by the guide action of the tapered portion. Can be improved. For example, it is not necessary to incorporate the front lower end pivot shaft 30 and the rear lower pivot shaft 31 by driving or pressing. In addition, two steps of a front lower end pivot shaft 30 and a rear lower pivot shaft 31 are respectively crimped to the boss body holes of the link members 19, 20, so that the front lower pivot shaft 30 and the rear lower pivot shaft are mounted. The axial strength of 31 can be maintained.

  As apparent from the above description and FIGS. 3 to 13, the vehicle includes a traveling machine body 11 on which the engine 8 is mounted, and a track frame 17 that is provided below the traveling machine body 11 and supports the traveling crawler 25 by winding. A work vehicle in which the track frame 17 is attached to the traveling machine body 11 via a link mechanism so as to be swingable back and forth, and the link mechanism is constituted by a pair of front and rear link members 19 and 20; Since the airframe 11, the pair of front and rear link members 19 and 20, and the track frame 17 form a four-bar link structure, the presence of the four-bar link structure causes, for example, the heel G or the back of the tractor 10 to be straddled. It is possible to support the traveling machine body 11 apart from a high crop, and provide a sufficient space for a ridge G or a tall crop. It can be coercive. In addition, while the structure can secure a sufficient space for ridges G or tall crops, etc., the forward and backward inclined posture of the traveling crawler 25 is greatly changed by the parallel link approximation operation of the four-bar link structure. Can be prevented. In addition, it is possible to prevent a significant variation in the ground resistance of the traveling crawler 25, and to reduce the risk of field disturbance and meandering.

  Next, a power transmission structure between the traveling crawler 25 and the driving wheel body 16 will be described with reference to FIGS. As shown in FIGS. 14 to 17, the bolt 87 is fastened to the inner hole edge side of the donut-shaped sheet metal rim body 86 on the disc-like mounting portion 15 a at the end of the rear axle 15 that protrudes outward from the rear axle case 14. . Bolts 88 are fastened to the inner hole edge side of the donut-shaped drive wheel body 16 on the outer peripheral edge side of the rim body 86. The drive wheel body 16 has a ring-shaped sprocket tooth bottom 89 and a pair of bifurcated sprocket teeth 90 serving as locking tooth bodies protruding in the radial direction from both sides of the sprocket tooth bottom 89. The sprocket tooth bottom 89 corresponds to a ring-shaped portion of the drive wheel body 16. A plurality of sets of sprocket tooth bodies 90 are provided at equal intervals throughout the sprocket tooth bottom 89. That is, the sprocket tooth bottom 89 is formed endlessly on the entire outer peripheral surface of the drive wheel body 16, while a pair of bifurcated sprocket teeth 90 project radially outward from both side edges of the sprocket tooth bottom 89, and the drive wheel A plurality of sets of sprocket tooth bodies 90 are arranged at equal intervals on the entire outer peripheral surface of the body 16.

  Further, the donut-shaped iron alloy drive wheel body 16 is formed by being divided into four partial wheel bodies 16a. The size of one partial ring body 16a is formed to a size of a quarter of the same circumference. The end surfaces 16b in the radiation direction are attached to each other, and the four partial ring bodies 16a are coupled in a ring shape, and the four partial ring bodies 16a are arranged on the same circumference to form the drive wheel body 16. The four partial ring bodies 16a are independently attached to and detached from the rim body 86, and any one of the four partial ring bodies 16a is configured to be replaceable. That is, since the four partial ring bodies 16a can be handled independently in an assembly operation or the like, the single component (one partial ring body 16a) can be reduced in weight and easily carried and assembled.

  15 and 18, the endless belt-like traveling crawler 25 includes a synthetic rubber crawler body 94 having a large number of lugs 25a formed on the outer peripheral surface side, and a plurality of cores embedded in the crawler body 94 at equal intervals. It consists of a metal body 95. The core metal body 95 includes a pair of core metal claw portions 95a that mesh the sprocket tooth bodies 90, a core metal barrel portion 95b that connects the core metal claw portions 95a, and a left-right direction from both ends of the core metal barrel portion 95b. Left and right wing pieces 95c. A plurality of sets of cored bar claws 95a are projected at equal intervals across the entire inner peripheral surface of the crawler body 94. Note that the entire core metal body 95 (including the core metal claw portion 95a) is covered with a synthetic rubber which is a constituent material of the crawler body 94.

  Further, a flat belt-like contact convex portion 94a is integrally formed on the inner peripheral surface of the crawler body 94 between the cored bar claws 95a adjacent to each other in the extending direction of the endless belt. A plurality of contact protrusions 94a are provided at equal intervals over the entire inner peripheral surface of the crawler body 94. In addition, between each contact convex part 94a, the inner peripheral convex surface part 94b which connects them is formed. The height of the inner peripheral convex surface portion 94b is formed to be lower than the height of the contact convex portion 94a that protrudes toward the inner peripheral side of the traveling crawler 25. The lateral displacement of the traveling crawler 25 can be prevented by the contact between the inner side surface of the pair of cored bar claws 95a and the contact convex portion 94a or the inner peripheral convex portion 94b. Further, by connecting the inner peripheral convex surface portion 94b, the rubber layer on the inner peripheral surface of the traveling crawler 25 can be formed with a layer thickness, the contact convex portion 94a is reinforced, and the inner peripheral side of the traveling crawler 25 (rubber such as the contact convex portion 94a). Layer) can be prevented from peeling off.

  That is, as shown in FIG. 15, when the traveling crawler 25 is wound around the driving wheel body 16, the contact convex portion 94 a is pressed by rubber contact with the sprocket tooth bottom 89 formed in a pulley shape, and is in contact with the sprocket tooth bottom 89. The low torque torque of the drive wheel body 16 is transmitted to the traveling crawler 25 side by friction between the convex portions 94a. Driving noise can be reduced by the rubber contact. Further, the sprocket tooth body 90 is fitted between the core metal claws 95a adjacent to each other in the extending direction of the endless belt, and the sprocket tooth body 90 is brought into contact with the metal core claws 95a by metal contact. The high torque rotational force of the driving wheel body 16 is transmitted to the traveling crawler 25 side by the engagement of the gold pawl portion 95a. Driving loss can be reduced by the metal contact, and occurrence of tooth jumping (idling) can be prevented.

  Further, as shown in FIG. 18, the cross-sectional end face shape of the sprocket tooth bottom 89 of the drive wheel body 16 is formed in a trapezoidal shape. The trapezoid outer peripheral side width c of the sprocket tooth bottom 89 and the metal core from the difference (ba) between the trapezoid inner peripheral width a of the sprocket tooth bottom 89 and the root inner width b of the claw 95a of the metal core 95. The difference (dc) between the front end side inner widths d of the 95 claw portions 95a is configured to be large.

  In addition, the largest difference (dc) between the trapezoid outer peripheral side width c of the sprocket tooth bottom 89 and the tip side inner width d of the claw portion 95a of the metal core 95 is formed, and compared with the difference (dc), A difference (da) between the trapezoid inner peripheral width a of the sprocket tooth bottom 89 and the tip inner width d of the claw 95a of the metal core 95 is formed small, and the trapezoid inner peripheral width a of the sprocket tooth bottom 89 is The difference (ba) in the root side inner width b of the claw portion 95a of the core metal body 95 is further reduced.

  As shown in FIGS. 1, 14 to 16, and 18, a traveling machine body 11 on which the engine 8 is mounted, a track frame 17 provided below the traveling machine body 11, a driving wheel body 16 and a driven wheel body on the track frame 17. In a work vehicle that includes left and right traveling crawlers 25 that are mounted via 21 and 23 and that has a plurality of metal cores 95 that mesh with the driving wheel body 16 in the traveling crawler 25, A contact convex portion 94a as a rubber belt body is provided at the portion, and the sprocket tooth bottom portion 89 as the annular portion of the driving wheel body 16 and the annular portions of the driven wheel bodies 21 and 23 abut against the contact convex portion 94a, so that the traveling crawler 25 is It is configured to rotate. Accordingly, during light load, the rotational force of the drive wheel body 16 is transmitted to the traveling crawler 25 by the friction drive between the sprocket tooth bottom 89 of the drive wheel body 16 and the contact convex portion 94a. On the other hand, during heavy load, the rotational force of the driving wheel 16 is transmitted to the traveling crawler 25 by metal contact between the metal core 95 and the toothed body (sprocket toothing 90) of the driving wheel 16. That is, while it is possible to reduce driving noise at light load, it is possible to reduce drive loss due to deflection and the like, and to prevent tooth jump at heavy load. Furthermore, the driven ring bodies 21 and 23 always roll on the contact convex portions 94a, and the metal contact sound generated from the driven ring bodies 21 and 23 can be reduced.

  As shown in FIGS. 15 and 18, a contact convex portion 94 a as a rubber belt body is provided in the central portion of the lateral width of the traveling crawler 25, and the contact convex portion 94 a is integrally formed on the inner peripheral surface of the traveling crawler 25. A sprocket tooth bottom 89 as a ring-shaped portion of the driving wheel body 16 and an outer peripheral surface as a ring-shaped portion of the driven wheel bodies 21 and 23 are configured to rotate on the contact convex portion 94a. Accordingly, during light load, the rotational force of the drive wheel body 16 is transmitted to the traveling crawler 25 by the friction drive between the sprocket tooth bottom 89 of the drive wheel body 16 and the contact convex portion 94a. That is, it is possible to reduce drive noise at light load. Wear of the driving wheel body 16 or the metal core body 95 can be prevented. On the other hand, during heavy load, the rotational force of the drive wheel body 16 is transmitted to the traveling crawler 25 by metal contact between the teeth of the metal core 95 and the drive wheel body 16. That is, the drive loss due to the deflection or sag of the traveling crawler 25 can be reduced. The tooth jump of the drive wheel body 16 can be prevented. Furthermore, since the driven wheel bodies 21 and 23 always roll on the contact convex portions 94a, the metal contact sound generated from the driven wheel bodies 21 and 23 portions can be reduced.

  As shown in FIGS. 15 and 18, left and right sprocket teeth 90 are protruded on both sides of the outer peripheral portion of the driving wheel body 16, and a sprocket tooth bottom 89 is formed between the left and right sprocket teeth 90. The metal core 95 is brought into metal contact with the sprocket tooth body 90, and the contact convex portion 94 a is brought into contact with the inner surface of the left and right sprocket tooth bodies 90 and the sprocket tooth bottom 89. Therefore, even when a side-slip force is applied to the traveling crawler 25, it is possible to easily prevent the traveling crawler 25 from being detached from the drive wheel body 16 due to the contact between the inner side surfaces of the left and right sprocket tooth bodies 90 and the contact convex portions 94a. . Due to the contact between the sprocket tooth bottom 89 formed on the entire outer periphery of the drive wheel 16 and the contact convex portion 94a of the traveling crawler 25, the friction surface between the sprocket tooth bottom 89 and the contact convex portion 94a can be widely formed. The contact surface pressure between 89 and the contact convex portion 94a can be reduced, and wear of the sprocket tooth bottom 89 or the contact convex portion 94a can be suppressed.

  As shown in FIGS. 15 and 18, the end surface of the sprocket tooth bottom 89 of the drive wheel body 16 is formed in a trapezoidal shape, and the trapezoid inner peripheral side width a of the sprocket tooth bottom 89 and the claw part base side of the metal core 95 are formed. The difference (cd) between the trapezoid outer peripheral side width c of the sprocket tooth bottom 89 and the inner width d of the tip of the claw part of the metal core is larger than the difference (ab) of the inner width b. doing. Therefore, it is possible to easily prevent the traveling crawler 25 from being detached from the driving wheel body 16 even when a side slip force is applied to the traveling crawler 25.

  Next, the structure of the drive wheel body 16 will be described with reference to FIGS. 17, 19, and 25. FIG. 17 is an explanatory diagram in which the driving wheel body 16 is disposed on the left side of the traveling machine body 11, and FIG. 19 is an explanatory diagram in which the driving wheel body 16 is disposed on the right side of the traveling machine body 11, and a flat rim body 86 on the rear axle 15. The through-hole 91 is formed in the rim body 86 and the bolt 88 is passed through the through-hole 91, while the screw hole 92 is formed in the drive wheel body 16, and the bolt 88 is inserted into the screw hole 92. The drive wheel body 16 is fastened to the rim body 86 by screwing.

  With the above configuration, in general, in the tractor 10 in which the forward movement time is longer than the reverse movement, of the sprocket tooth bodies 90 of the drive wheel body 16, the tooth bodies 90 that abut on the cored bar claw portion 95 a by forward movement. The forward side wears more than the reverse side. For example, when the advancing side surface of the sprocket tooth body 90 is worn, the driving wheel body 16 arranged on the left side of the traveling machine body 11 as shown in FIG. 17 is arranged on the right side of the traveling machine body 11 as shown in FIG. The forward side surface of the sprocket tooth body 90 in FIG. 17 is the reverse side surface in FIG. 19, and the reverse side surface in FIG. 17 is the forward side surface in FIG. That is, by replacing the left and right driving wheel bodies 16 on the left and right sides of the traveling machine body 11, the left and right driving wheel bodies 16 can be used with the reverse side surface with less wear as the forward side surface, and the service life of the driving wheel body 16 is increased. Thus, the part replacement cost can be reduced. Further, since the contact surface (fastening surface) of the drive wheel body 16 with respect to the rim body 86 is the same surface on the left side and the right side of the traveling machine body 11, only the contact surface (one side surface) of the drive wheel body 16 is milled. The processing cost can be reduced.

  Further, as shown in FIG. 25, the driving wheel body 16 is formed by being divided into four partial ring bodies 16a, and the four partial ring bodies 16a are joined in a ring shape by attaching the end faces 16b in the radial direction. In the structure arranged on the circumference, an attachment step 16c is formed on each end face 16b on both ends of the drive wheel body 16 respectively. A through hole 16d is formed in the attachment step 16c of one end face 16b that is formed to be thin. A screw hole 16e is provided in the attachment step 16c of the other end surface 16b formed to be thick.

  That is, the partial ring body 16a is brought into contact with one side surface of the rim body 86, and the rim body 86 and the partial ring body 16a are contacted from the other side surface of the rim body 86 via the through hole 91 and the through hole 16d. The bolt 88 is inserted, and then the bolt 88 is inserted into the screw hole 16e of the adjacent partial ring body 16a. The joining step portions 16 c of the adjacent partial ring bodies 16 a are combined, and the adjacent partial ring bodies 16 a are fastened to the rim body 86 on one side surface of the rim body 86. Therefore, the fixed position of each partial ring body 16a can be easily determined by the combination of the attachment step portions 16c of each partial ring body 16a. In addition, the operator can hold the tool with the other hand while screwing the bolt 88 while supporting the partial ring body 16a with one hand.

  Next, the structure of the rear crawler traveling device 13 will be described with reference to FIGS. 9, 22 to 24, and 26. As shown in FIG. 26, the traveling crawler 25 is stretched on the track frame 17 via the drive wheel body 16, the driven wheel bodies 21 and 23, and the rolling wheel 26. On the other hand, the left and right width center lines Q of the driven wheels 21 and 23 and the rolling wheels 26 are offset by a certain width S toward the inside of the machine body. That is, the driving wheel 16 is in a position where the tooth bottom 89 contacts the outside of the core claw 95a of the traveling crawler 25, and the driven wheels 21, 23 and the rolling wheel 26 are in contact with the inside. , Each offset.

  With the configuration described above, the grounding side of the traveling crawler 25 is supported by the driven wheel bodies 21 and 23 and the rolling wheel 26, so that the side slip force (outward force) of the traveling crawler 25 in the turning outer direction is driven wheel body. 16 is prevented. The driving wheel 16 is properly meshed with the traveling crawler 25. For example, the traveling crawler from the driving wheel body 16 even in a traveling state in which a side slip force (outward force) in the direction of the turning outer side is easily generated or when the traveling drive load moves at a high speed under a high load state. 25 can be prevented from leaving.

  As shown in FIG. 22, the shape of the end surface of the tooth bottom portion 89 cut in the axial direction in the tooth bottom portion 89 of the drive wheel body 16 is formed in an asymmetric trapezoidal shape with respect to the center of the left-right width of the drive wheel body 16. Therefore, the tooth bottom portion 89 of the drive wheel body 16 is formed such that the machine inside width U of the end face is larger than the machine outside width T of the end face with respect to the lateral center line P of the drive wheel body. Therefore, the drive wheel body 16 can be formed lighter while the drive wheel body 16 can be easily offset to the outer side of the driven wheel bodies 21 and 23 and the rolling wheel 26.

  As shown in FIG. 23, on the inner peripheral surface of the traveling crawler 25, the surface through which the tooth bottom 89 of the driving wheel 16 passes or the surface through which the driven wheels 21 and 23 pass is low and the inside of the airframe is high. It is formed on the inclined surface, and the tension of the traveling crawler 25 is increased by the inclined surface with respect to the side slip force that the traveling crawler 25 moves outward of the machine body. That is, it generates a reaction force (inward force) that moves the traveling crawler 25 inward of the machine against the side slip force (outward force) of the traveling crawler 25, and prevents the traveling crawler 25 from being detached. Alternatively, uneven wear of the traveling crawler 25 is suppressed. In addition, the inner peripheral surface of the traveling crawler 25 may be formed on the surface through which the tooth root portion 89 of the driving wheel body 16 passes on an inclined surface that is higher on the outer side of the body and lower on the inner side of the body. Similarly to the inner peripheral surface of the traveling crawler 25, the tooth bottom 89 may be inclined.

  As shown in FIG. 24, a part of the inner peripheral surface of the traveling crawler 25 with which the inner side of the peripheral surface of the rolling wheel 26 abuts is formed on the convex inner peripheral surface 25b. The convex inner peripheral surface 25b is The core claw portion 95a is formed so as to protrude most toward the inner peripheral side of the traveling crawler 25. The convex inner peripheral surface 25 b is configured to be inclined toward both side edges of the traveling crawler 25. That is, on the ground contact side of the traveling crawler 25, the convex inner peripheral surface 25b is formed on an inclined surface that is highest at a position close to the cored bar claw portion 95a and decreases toward both side edges of the traveling crawler 25. ing.

  With the above configuration, a force for returning the traveling crawler 25 to a predetermined position is generated with respect to a side slip force that the traveling crawler 25 shifts to the outer side or the inner side of the body, thereby suppressing uneven wear of the traveling crawler 25 or the rolling wheels 26. . In other words, the convex inner peripheral surface 25b of the traveling crawler 25 applies an outward force to the left and right wheels of the rolling wheel 26, so that the rolling wheel 25 and the rolling wheel 26 are balanced at the center position. The traveling crawler 25 is supported by 26. That is, the contact between the rolling wheel 26 and the cored bar claw portion 95a can be reduced, the contact between the rolling wheel 26 and the cored bar claw portion 95a can be prevented, and the generation of the metal contact noise can be suppressed. .

  As shown in FIGS. 1, 9, and 26, the vehicle includes a traveling machine body 11 on which the engine 8 is mounted, a track frame 17 provided on the lower side of the traveling machine body 11, and a traveling crawler 25 attached to the track frame 17. In the work vehicle in which the traveling crawler 25 is stretched on the track frame 17 via the body 16, the front driven wheel body 21, the rear driven wheel body 23, and the rolling wheel 26, The left and right width center lines Q of the driven wheel bodies 21 and 23 and the rolling wheels 26 are offset by a certain width S toward the inside of the machine body. Therefore, it is possible to easily prevent the force in the turning outer side (side slip force) from acting on the drive wheel body 16. That is, the front driven wheel body 21, the rear driven wheel body 23, and the rolling wheel 26 are offset toward the inside of the machine with respect to the driving wheel body 16, so that the front driven wheel body 21, the rear driven wheel body 23, and the rolling wheel 26 are offset. By supporting the grounding side of the traveling crawler 25, the driving wheel body 16 can be properly meshed with the traveling crawler 25, and an increase in traveling driving load can be prevented. For example, when the traveling machine body 11 turns, even if a force (slipping force) in the direction of the turning outer side is likely to be generated, or even when the traveling drive load moves at a high speed with a high load, the traveling vehicle body 11 travels. The crawler 25 can be prevented from separating.

  As shown in FIG. 26, the driving wheel 16 is in a position where the sprocket tooth bottom 89 is in contact with the outer side of the core metal claw 95a of the traveling crawler 25, and the front driven wheel 21 and the rear driven wheel 23. The rolling wheels 26 are offset to the positions where they contact each other. Therefore, it is possible to reduce the force with which the driving wheel body 16 or the front driven wheel body 21 and the rear driven wheel body 23 or the rolling wheel 26 abut on the core metal claw portion 95a of the traveling crawler 25, and the core metal claw portion 95a or the driving wheel. Uneven wear of the body 16 or the front driven wheel body 21 and the rear driven wheel body 23 or the rolling wheel 26 can be reduced.

  As shown in FIG. 22, among the sprocket tooth bottom portions 89 of the drive wheel body 16, the shape of the end surface of the tooth bottom portion 89 cut in the axial direction is formed in an asymmetric trapezoidal shape with respect to the center of the left and right width of the drive wheel body 16. doing. Accordingly, the inner side of the fuselage is formed wider than the outer side of the fuselage 89 at the end surface of the tooth bottom 89, the driving wheel 16 can be reduced in weight, and the engagement between the traveling crawler 25 and the driving wheel 16 can be properly maintained. The driving wheel body 16 can be easily offset outward from the front driven wheel body 21, the rear driven wheel body 23, and the rolling wheel 26. In addition, by forming the end face of the tooth bottom portion 89 in a trapezoidal shape, the manufacturing cost or the own weight of the drive wheel body 16 can be reduced as compared with, for example, a square shape.

  As shown in FIG. 23, on the inner peripheral surface of the traveling crawler 25, the surface through which the tooth bottom portion 89 of the driving wheel body 16 passes, or the surface through which the front driven wheel body 21 and the rear driven wheel body 23 pass, It is formed on an inclined surface that is low and has a high inside. Therefore, it is possible to increase the tension of the traveling crawler 25 by the inclined surface with respect to the side slip force that the traveling crawler 25 moves outward of the machine body. That is, a reaction force that moves the traveling crawler 25 toward the inside of the machine body is generated with respect to the side slip force of the traveling crawler 25, so that the traveling crawler 25 can be prevented from being detached or uneven wear of the traveling crawler 25 can be easily suppressed. .

  As shown in FIG. 24, a part of the inner peripheral surface of the traveling crawler 25 with which the inside abuts out of the peripheral surface of the rolling wheel 26 is formed in a convex shape by a convex inner peripheral surface 25b. Therefore, it is possible to generate a force for returning the traveling crawler 25 to a predetermined position with respect to a side slip force that the traveling crawler 25 shifts to the outer side of the machine body or the inner side of the machine body, and uneven wear of the traveling crawler 25 or the rolling wheels 26 can be easily performed. Can be suppressed.

  Furthermore, as shown in FIGS. 20-21, the inner peripheral convex surface part 94b is formed in the inner peripheral surface between each metal core claw part 95a adjacent to the left-right width direction of an endless belt among the inner peripheral surfaces of the crawler main body 94. Has been. The height dimension H2 of the metal core claw portion 95a with respect to the inner peripheral convex surface portion 94b is formed larger than the height dimension H1 of the metal core claw portion 95a with respect to the passing surface (convex inner peripheral surface 25b) of the rolling wheel 26. The rubber portion of the crawler body 94 is raised by forming the inner peripheral convex surface portion 94b between the core metal claws 95a adjacent to each other in the left-right width direction of the endless belt. Therefore, the front driven wheel body 21 and the rear driven wheel body 23 can pass over the inner peripheral convex surface portion 94b, and vibration or noise associated with driving of the traveling crawler 25 can be reduced.

  On the other hand, the distance between the passing surface (convex inner peripheral surface 25 b) of the rolling wheel 26 and the upper surface of the root portion of the blade piece 95 c of the metal core 95, that is, the thickness dimension of the crawler body 94 at the passing surface portion of the rolling wheel 26. Compared with H3, the thickness dimension H4 of the crawler body 94 between the cored bar claws 95a adjacent to the endless belt in the left-right width direction (upper side of the cored bar body 95b) is formed larger. For this reason, a difference in height between the central portion of the crawler body 94 in the left-right width and the upper portion of the cored bar claw portion 95a can be secured, and even when a side-sliding force or a tilting force acts on the traveling crawler 25, the traveling crawler 25 can be prevented from being detached. .

  Further, a cored bar body 95b is protruded on the outer peripheral side of the traveling crawler 25, and reinforcing steel cords 96 are embedded on both sides of the cored bar body 95b in the crawler main body 94. The crawler body 94 is configured to have a minimum thickness. Further, the cored bar 95 is formed with a width H5 of the cored bar body 95b wider than the width H6 of the blade piece 95c. Therefore, the strength of the core metal body 95 can be secured, and, for example, a concave portion is formed on the surface of the core metal barrel portion 95b to increase the rubber bonding area with the crawler main body 94, so It is possible to reduce separation of the crawler main body 94 and muddy water from entering between the crawler main body 94 and the metal core 95.

  As is clear from the above description and FIGS. 18, 23, and 26, a plurality of metal cores 95 are provided at equal intervals on the inner circumferential side of the traveling crawler 25, and the traveling crawler 25 is driven to rotate. On the outer peripheral side of the ring body 16, a sprocket tooth body 90 (locking tooth body) that engages with the core metal body 95 and a sprocket tooth bottom 89 (annular portion) are provided, and an inner peripheral side of the traveling crawler 25. Is provided with a contact convex portion 94a (rubber belt body), and the traveling crawler 25 is driven to circulate when the sprocket tooth bottom portion 89 of the driving wheel body 16 abuts against the contact convex portion 94a. Therefore, not only the engagement of the sprocket tooth body 90 of the drive wheel body 16 and the core metal body 95 of the traveling crawler 25 but also the sprocket tooth bottom 89 of the drive wheel body 16. By friction drive between the convex contact portion 94a, it becomes possible to transmit the rotational force of the driving wheel 16 in the traveling crawler 25. Accordingly, it is possible to reduce the metal contact sound due to the engagement between the sprocket tooth body 90 of the driving wheel body 16 and the metal core body 95 of the traveling crawler 25. That is, the driving noise of the traveling crawler 25 can be reduced.

  Next, with reference to FIGS. 24 and 27 to 36, a support structure for the rolling wheel 26 having a pair of left and right track rollers 26a will be described. As shown in FIGS. 24 and 27, a roller support cylinder 111 as a rolling wheel support is bolted to the lower surface of the track frame 17. A roller shaft body 113 is rotatably supported via a pair of bearing bearings 112. Both end sides of the roller shaft body 113 protrude from the left and right openings of the roller support cylinder 111 toward the left and right outer sides. A pair of left and right track rollers 26 a are fixed to both ends of the roller shaft body 113 by fastening nuts 114. A dust seal 115 is provided outside the bearing bearing 112 in the left and right openings of the roller support cylinder 111. Note that a lubricating oil (grease) is filled between the pair of bearing bearings 112.

  Further, as shown in FIG. 27, a dust seal 115 is fitted on the roller shaft body 113 outside the bearing bearing 112 via a sleeve 116 (or collar). An abrasion suppression plate 117 is sandwiched between the track roller 26 a and the sleeve 116. That is, when the fastening nut 114 is tightened, the sleeve 116 and the wear suppressing plate body 117 are fixed between the track roller 26a and the bearing bearing 112, and the wear suppressing plate body 117 is brought into contact with the lip 115a of the dust seal 115. Therefore, wear of the lip 115a and the contact surface thereof due to muddy water intrusion can be suppressed, and muddy water intrusion into the bearing bearing 112 can be prevented.

  Further, as shown in FIG. 28, a labyrinth recess 111a is formed at the left and right opening edges of the roller support cylinder 111, and the outer peripheral side end surface 117a of the wear suppression plate 117 is bent toward the roller support cylinder 111, thereby forming the labyrinth recess. The outer peripheral side end surface 117a is inserted in a loosely fitting manner in 111a, and a labyrinth gap is formed by the labyrinth concave portion 111a and the outer peripheral side end surface 117a, so that wrapping of grass or the like, or intrusion of muddy water is suppressed, and the dust seal 115 is damaged. May be prevented.

  Further, as shown in FIG. 29, a labyrinth multi-step portion 111b is formed on the left and right opening edges of the roller support cylinder 111, and a multi-step end surface 26b similar to the labyrinth multi-step portion 111b is formed on the opposing surface of the track roller 26a. The labyrinth multi-step portion 111b may be faced with a multi-step end surface 26b having a similar shape to form a labyrinth gap to prevent wrapping of grass or mud water and to prevent damage to the dust seal 115.

  30 is a partially enlarged view of the front driven wheel body 21 (or the rear driven wheel body 23). The driven wheel bodies 21 and 23 are pivotally supported on the driven wheel shaft body 21 via the bearing bearing 112, and the track frame. In the structure in which the driven wheel shaft body 221 is fastened to the nut 114 by the driven wheel holder 222 provided in the structure 17, as shown in FIG. 27, the dust seal 115, the sleeve 116, and the wear suppression plate 117 are assembled, and the fastening nut 114 is tightened. The sleeve 116 and the wear suppressing plate 117 are fixed between the driven wheel holder 222 and the bearing bearing 112, the wear suppressing plate 117 is brought into contact with the lip 115a of the dust seal 115, and the lip 115a and its Wear of the contact surface can be suppressed, and muddy water can be prevented from entering the bearing bearing 112.

  Next, the structure of the track frame 17 and the tension adjusting mechanism 22 will be described with reference to FIGS. 3, 4, and 31 to 33. As shown in FIGS. 31 and 32, the tension adjusting mechanism 22 includes a base frame 225 that is fixed to the upper surface of the front portion of the track frame 17, an outer cylinder 226 that is fixed to the upper surface of the base frame 225, the base frame 225, and the outer cylinder. A rectangular inner space 227 formed by the end frame quadrilateral inner cylinder 227 and the base frame 225 and the outer cylinder 226 are inserted into the rectangular space formed by the H.226 through the front opening. A support plate 228 that closes the opening; a tension bolt 229 that is rotatably supported by the support plate 228; and a slide cylinder 230 that is screwed into a tension screw portion 229a of the tension bolt 229 that extends into the inner cylinder 227. A tension spring seat 231 fixed to the slide cylinder 230 as a screwed body, and a driven wheel holder 222 fixed to the front end of the inner cylinder 227 And a tension spring 232 provided between the Nshonbane seat 231.

  As shown in FIGS. 31 and 33, a tension spring 232 is wound and supported on the outer peripheral side of the slide cylinder 230 so as to be loosely fitted. The tension spring seat 231 is connected to the tension screw portion 229a of the tension bolt 229 via the slide cylinder 230. Further, the elastic stopper body 233 is fixed to the end of the tension bolt 229 on the side that protrudes rearward of the outer cylinder 226. The elastic stopper body 233 is brought into contact with the inner surface side of the support plate body 228. The end of the tension bolt 229 is protruded from the rear outer side of the outer cylindrical body 226. An anti-spinning nut body 234 is screwed onto the protruding end screw portion 229b of the tension bolt 229. A rotation operation square head portion 229c is formed on the protruding end screw portion 229b of the tension bolt 229.

  That is, the protruding end screw portion 229b is passed through the support plate body 228, the elastic stopper body 233 is pressure-bonded to the inner surface side of the support plate body 228, and the idling prevention nut 234 is pressure-bonded to the outer surface side of the support plate body 228. The tension bolt 229 is fixedly supported, and the tension spring 232 force is received by the tension spring seat 231. An outer cylinder 226 and an inner cylinder 227 are provided as extendable idler forks that support the front driven wheel 21. The front and rear lengths of the outer cylinder body 226 and the inner cylinder body 227 are extended by a tension spring 232 so that the tension of the traveling crawler 25 is maintained substantially constant.

  As shown in FIGS. 31 and 33, a tension bolt 229 is provided on the support plate 228 that is a part of the idler fork, and the tension spring 232 is received by the tension spring seat 231 and the tension spring 232 is applied to the tension bolt 229. It is configured to adjust with. That is, with the idling prevention nut 234 in the loosened state, a wrench (not shown) is locked to the rotation operation square head 229c as the operation portion of the tension bolt 229 that is connected to the idler fork so as to be freely rotatable. The tension bolt 229 is rotated by a wrench, the connection length between the tension bolt 229 and the slide cylinder 230 is changed, and the tension spring 232 is pushed out toward the front of the outer cylinder 226 by the tension spring seat 231. The force of the tension spring 232 is increased by the pushing operation of the tension spring 232, and the front part of the inner cylinder 227 is pushed forward from the front opening of the outer cylinder 226.

  As a result, when the tension of the traveling crawler 25 decreases, the front driven wheel body 21 is moved in front of the track frame 17 by the rotation operation of the tension bolt 229, and the tension of the traveling crawler 25 is increased. To maintain a constant tension. As shown in FIG. 33, when the protruding length LB of the inner cylinder 227 protruding from the front end opening of the outer cylinder 226 is long (the state shown in FIG. 33), that is, the distance Lx between the inner cylinder 227 and the support plate 228 is When it is larger than the spring stroke LC that is the distance between the driven wheel holder 222 and the slide cylinder 230, the spring stroke LC that is the distance between the driven wheel holder 222 and the slide cylinder 230 is kept substantially constant. That is, when the interval Lx is larger than the spring stroke LC, the stroke of the tension spring 232 is determined by the interval Lx.

  On the other hand, when the protruding length LA of the inner cylinder 227 protruding from the front end opening of the outer cylinder 226 is short, that is, the distance Lx between the inner cylinder 227 and the support plate 228 is the driven wheel holder 222 and the slide cylinder 230. The spring stroke LC, which is the distance between the driven wheel holder 222 and the slide cylinder 230, is kept substantially constant as long as the tension of the traveling crawler 25 is equal to or higher than the spring stroke LC, which is the distance between the driven wheel holder 222 and the slide cylinder 230. . In the state in the middle of the assembly before the tension is applied to the travel crawler 25 shown in FIG. Change. That is, since the spring stroke LC varies with the variation in the tension of the traveling crawler 25, when the distance Lx is smaller than the spring stroke LC, the stroke of the tension spring 232 may be determined by the spring stroke LC.

  Further, since the protruding amount of the angular head 229c for rotating operation that protrudes outside the support plate 228 is always constant and the corner 229c is supported at a substantially constant position outside the support plate 228, the front lower end A sufficient space for mounting a wrench or the like as a rotary operation tool can be secured between the bearing cylinder 77 of the pivot shaft 30 and the square head 229c.

  Positioning holes 239 are respectively formed in the outer cylinder 226 as a stationary side case body of the idler hawk and the inner cylinder 227 as a movable side case body of the idler hawk. When the inner cylinder 227 is assembled to the outer cylinder 226, the positioning hole 239 of the inner cylinder 227 is aligned with the positioning hole 239 of the outer cylinder 226, and a rod-like body such as a pin is inserted into each positioning hole 239. The idling prevention nut body 234 and the like can be attached in a state where the inner cylinder 227 is fixed to the outer cylinder 226 and the outer cylinder 226 and the inner cylinder 227 are prevented from being displaced or dropped.

  A stroke restricting structure of the tension spring 232 will be described with reference to FIGS. 34 to 36. As shown in FIG. 34, a spring compression stopper 241 is provided on the driven wheel holder 222 facing the tension spring seat 231 of the tension bolt 229, and the spring compression stopper 241 is disposed on the driven wheel holder 222 as a part of the idler fork. The tension spring seat 231 is brought into contact with the spring compression stopper 241, and the compression amount of the tension spring 232 is regulated by the spring compression stopper 241. The tension screw portion 229a of the tension bolt 229 is screwed to the screw portion 228a of the support plate body 228, and the tension bolt 229 is fixed to the support plate body 228 by the idling prevention nut body 234, while the idling prevention nut body 234 is fixed. Loosen and rotate the tension bolt 229 to adjust the tension spring 232 force.

  As shown in FIG. 35, a spring compression stopper 242 is also provided on the tension spring seat 231 so as to face the spring compression stopper 241 in FIG. 34, and the amount of compression of the tension spring 232 is adjusted by the contact of the spring compression stoppers 241 and 242. It may be regulated. Also, as shown in FIG. 36, a cylindrical spring compression stopper 243 is provided outside the tension spring 232, the tension spring seat 231 is brought into contact with the spring compression stopper 243, and the amount of compression of the tension spring 232 by the spring compression stopper 241. May be regulated.

  A mud adhesion preventing structure for the track frame 17 will be described with reference to FIGS. As shown in FIGS. 3, 4, and 13, a square plate shape is formed on the flat upper surface between the front lower end pivot shaft 30 and the rear lower pivot shaft 31 among the flat upper surfaces of the rectangular columnar track frame 17 that is long in the front-rear direction. The frame reinforcing ribs 246 are fixed upright. The lower end edge of the frame reinforcing rib 246 is welded and fixed to the inner side of the body of the flat upper surface of the track frame 17. That is, the frame reinforcing ribs 246 are offset from the center of the left and right widths of the flat upper surface of the track frame 17 on the inner side of the body.

  In addition, a square plate-like sliding cover 247 as a mud sliding member is provided on the upper surface side of the track frame 17. The upper and lower end edges of the sliding cover 247 are welded and fixed to the outer end of the airframe and the upper end edge of the frame reinforcing rib 246 on the flat upper surface of the track frame 17. Frame reinforcing ribs 246 and sliding covers 247 as mud sliding bodies are erected in a mountain shape within the left and right width of the track frame 17. The sliding cover 247 is arranged in an outward chute shape. The mud falling on the upper surface of the track frame 17 slides by the guide of the sliding cover 247, reduces the amount of mud deposited on the upper surface of the track frame 17, and prevents the mud from accumulating on the upper surface of the track frame 17. Yes. The frame reinforcing rib 246 and the sliding cover 247 are formed as reinforcing parts for the track frame 17. While the truck frame 17 can be reduced in weight or cost can be reduced, the support rigidity of the traveling crawler 25 can be easily improved.

  As shown in FIGS. 1, 3, 4, and 31 to 33, a traveling machine body on which the engine 8 is mounted, a track frame 17 provided on the lower side of the traveling machine body 11, and a follower wheel body 21 via a track frame 17. A traveling crawler 25 to be mounted, an outer cylindrical body 226 and an inner cylindrical body 227 as telescopic idler forks that support the front driven wheel body 21, and a tension spring 232 for extending the outer cylindrical body 226 and the inner cylindrical body 227. The work vehicle is provided with tension bolts 229 on the outer cylinder body 226 and the inner cylinder body 227, and the tension spring 232 force is received by the tension spring seat 231 and the tension spring 232 force is adjusted by the tension bolt 229. Thus, the rotation operation corner head 229c as the operation portion of the tension bolt 229 is connected to the outer cylinder 226 and the inner cylinder 227 so as to be freely rotatable. And it connects the tension spring seat 231 via the slide cylindrical body 230 of the threaded body to the tension screw portion 229a of the tension bolt 229. Therefore, although the tension adjusting structure is provided with the tension bolt 229, only the operation portion 229c of the tension bolt 229 protrudes from the outer cylinder 226 and the inner cylinder 227 to operate the tension adjusting tool of the traveling crawler 25. A wide space for mounting on the portion 229c can be formed. A work space for adjusting the force of the tension spring 232 can be easily secured. Further, when adjusting the force of the tension spring 232, the trouble of using a grease injection device or the like can be saved.

  As shown in FIGS. 3, 4, and 31 to 33, the side surface portion of the outer cylindrical body 226 as the stationary side case body of the idler fork and the side surface of the inner cylindrical body 227 as the movable side case body of the idler fork. A positioning hole 239 into which a pin or the like can be simultaneously inserted is formed in each part. Therefore, in assembly work, a pin or the like can be inserted into the positioning hole 239, and the inner cylinder 227 can be easily temporarily fixed to the outer cylinder 226, so that the displacement or dropping of the inner cylinder 227 can be easily prevented. Assembling workability of the tension spring 232 can be improved.

  As shown in FIGS. 3, 4, and 13, a frame reinforcing rib 246 or a sliding cover 247 as a mud sliding body is provided on the upper surface side of the track frame 17. Therefore, even if mud falls from the non-grounded side of the traveling crawler 25, the mud can be dropped to the road surface side by the guide of the frame reinforcing rib 246 or the sliding cover 247, and the mud is moved to the upper surface side of the track frame. Accumulation can be prevented. It is possible to prevent the driving load from increasing due to mud adhering to the traveling crawler 25 portion, and to reduce the traveling driving load and improve the fuel efficiency. The variation in the weight of the traveling crawler 25 can be reduced, the fluctuation range of the tension of the traveling crawler 25 can be reduced, the power transmission efficiency to the traveling crawler 25 can be stabilized, and the vibration accompanying the driving of the traveling crawler 25 can be reduced.

  As shown in FIGS. 3, 4, and 13, frame reinforcing ribs 246 and sliding covers 247 are erected in a mountain shape within the lateral width of the track frame 17. Accordingly, it is possible to prevent the frame reinforcing rib 246 and the sliding cover 247 from being deformed and damaged by mud or the like lifted from the ground contact side of the traveling crawler 25. While the frame reinforcing rib 246 and the sliding cover 247 can be reduced in weight, the rigidity or durability of the frame reinforcing rib 246 and the sliding cover 247 and the track frame 17 can be improved.

  As apparent from the above description and FIGS. 1, 3, 4, and 31 to 33, the track frame 17 includes a driven wheel body 21 around which the traveling crawler 25 is wound, The outer cylindrical body 226 and the inner cylindrical body 227 as extendable idler forks that support the driven wheel body 21, and a tension spring 232 that biases the driven wheel body 21 toward the inner peripheral side of the traveling crawler 25. Therefore, for example, the tension of the traveling crawler 25 can be adjusted and maintained by a simple tension adjusting structure provided with the tension bolt 229.

  Next, the detailed structure of the crawler guide body 41 will be described with reference to FIGS. 3, 4, and 37 to 39. As shown in FIGS. 3, 4, and 38, a roller support cylinder 111 as a rolling wheel support is bolted to the lower surface of the track frame 17. As can be seen from the three front and rear rolling wheels 26 of the embodiment, the roller support cylinder 111 is also arranged on the lower surface of the track frame 17 in front and rear. A crawler guide body 41 is detachably attached to the front roller support cylinder 111 and the rear roller support cylinder 111 by two bolts 250 from below.

  As shown in FIG. 3, FIG. 4, FIG. 37 and FIG. 38, each crawler guide body 41 is formed in a boat shape having an inverted T-shape in side view. In the crawler guide body 41, the one longitudinal end side and the other longitudinal end side are formed in an asymmetric shape. In the embodiment, the distances D1 and D2 from the vertical imaginary line PL orthogonal to the axis of the roller shaft body 113 of the rolling wheel 26 are the distance D1 of the longitudinal one end 251 facing the driven wheel bodies 21 and 23 is the center. The distance D2 is longer than the distance D2 of the other longitudinal end 252 facing the rolling wheel 26 (D1> D2). On each longitudinal end side 251 of each crawler guide body 41, an extension portion 253 narrower than the lateral width of the longitudinal middle portion of the crawler guide body 41 is formed. As shown in FIG. 39, in the embodiment, the lateral width W of the extension 253 is set to be equal to or larger than the lateral width Wo of the outer peripheral tip side of the driven wheels 21 and 23 (W ≧ Wo). On the other hand, the other longitudinal end side 252 of each crawler guide body 41 is curved so as to protrude upward.

  As is apparent from the above description and the description of FIGS. 3, 4, and 38, the traveling machine body 11 on which the engine 8 is mounted, the track frame 17 provided at the lower part of the traveling machine body 11, the drive wheel body 16, and the slave body. A working vehicle comprising a moving crawler body 21 and 23, a rolling wheel 26 and a traveling crawler 25 mounted on the track frame 17 via a crawler guide body 41, wherein the crawler guide body 41 has a boat shape in a side view. The crawler guide body 41 requires the longitudinal one end 251 because the longitudinal one end 251 facing the driven wheel bodies 21 and 23 and the other longitudinal end 252 are formed in an asymmetric shape. The shape is specially designed for various functions, and the traveling crawler 25 is effectively prevented from falling off due to a side-slip force or the like by adapting to the angle of attack or the backside angle of the traveling crawler 25. It can be. Further, the other longitudinal end 252 of the crawler guide body 41 has a shape specialized for a necessary function, and even if the traveling crawler 25 is bent due to a stone or a step on the ground, the traveling crawler 25 The inner peripheral side is pressed against the crawler guide body 41, and the crawler guide body 41 can be prevented from being worn, deformed or damaged, or the inner peripheral side of the traveling crawler 25 can be damaged.

  Further, as apparent from the above description and the description of FIGS. 3, 4, and 37 to 39, the longitudinal end side 251 of the crawler guide body 41 has a lateral width of the longitudinal middle portion of the crawler guide body 41. Since the narrow extension portion 253 is formed, the distal end side of the extension portion 253 can be disposed close to the driven wheel bodies 21 and 23. Accordingly, for example, the followability of the traveling crawler 25 (core metal body 95) with respect to the longitudinal one end 251 of the crawler guide body 41 can be improved, and even if a side slip force or the like acts on the traveling crawler 25. The traveling crawler 25 can be reliably prevented from falling off from the driven wheel bodies 21 and 23, the rolling wheel 26 and the like.

  Further, as apparent from the above description and the description of FIG. 39, the lateral width W of the extension 253 is set to be equal to or larger than the lateral width Wo of the outer peripheral tip side of the driven wheel bodies 21, 23. Thus, even if a side slip force acts on the crawler guide body 41, the side crawler 25 can prevent the traveling crawler 25 from falling off between the driven wheels 21 and 23 and the crawler guide body 41. The metal core 95 of the traveling crawler 25 moves laterally smoothly. Further, the movement of the metal core 95 or the like from the driven wheel body 21 to the crawler guide body 41 (the movement of the traveling crawler 25), the metal core 95 or the like from the crawler guide body 41 to the driven wheel body 23, or the like. Can move smoothly. Therefore, the traveling crawler 25 can be more accurately prevented from falling off from the driven wheel bodies 21 and 23, the rolling wheel 26, and the like.

  Moreover, as is apparent from the above description and the description of FIGS. 3, 4 and 38, the crawler guide body is mounted on the roller support cylinder 111 serving as a rolling wheel support that rotatably supports the rolling wheel 26. Since 41 is detachably attached, the number of crawler guide bodies 41 can be increased or decreased in accordance with the number of rolling wheels 26 installed. For example, when one or more intermediate rolling wheels 26 are provided between the front and rear rolling wheels 26, the crawler guide body 41 may be attached to the intermediate rolling wheels 26 other than the front and rear rolling wheels 26 as necessary. The traveling crawler 25 can be prevented from dropping off according to work conditions and the like.

  Next, an example of the traveling crawler 25 that can be attached to the rear crawler traveling device 13 will be described with reference to FIGS. 40 to 42. The traveling crawler 25 shown in FIG. 40 is the traveling crawler 25 of the standard specification described so far in the embodiment. In the traveling crawler 25 of the standard specification, the traveling crawler 25 uses the left-right width center line P of the metal core 95, the contact convex portion 94a, and the inner peripheral convex surface portion 95b, that is, the left-right width center line P of the engaged portion in the traveling crawler 25. It is offset by a predetermined width S1 on the inner side of the machine body (the inner side of the left and right) with respect to its own left and right width center line Ca. Further, as described above, the left and right width center lines Q of the driven wheel bodies 21 and 23 and the rolling wheels 26 are offset by a predetermined width S on the inner side of the body with respect to the left and right width center line P of the driving wheel body 16. . That is, the driving wheel body 16 is located at a position where the sprocket tooth bottom 89 comes into contact with the outer side of the core claw part 95a of the traveling crawler 25, and the driven wheel bodies 21, 23 and the rolling wheel 26 are located at positions where the inner side contacts. , Each offset.

  The traveling crawler 25 shown in FIG. 41 has an offset specification traveling in which the tread between the left and right rear crawler traveling devices 13 is enlarged by projecting greatly from the driving wheel body 16 and the like to the outer side (right and left outer sides). Crawler 25. The lateral width W2 of the offset traveling crawler 25 is the same as the lateral width W1 of the standard traveling crawler 25 (W2 = W1). In the traveling crawler 25 of the offset specification, the left and right width center line P of the engaged portion in the traveling crawler 25 is a predetermined width S1 on the inner side (left and right inner side) of the body relative to the left and right width center line Ca of the traveling crawler 25 itself. It is offset by a larger width S2. However, the point that the left and right width center lines Q of the driven wheels 21 and 23 and the rolling wheels 26 are offset by a predetermined width S toward the inner side of the machine body with respect to the left and right width center line P of the driving wheel body 16 is a standard specification. It is common with the traveling crawler 25. In this case, the tread between the left and right rear crawler travel devices 13 can be changed only by replacing the travel crawler 25 without adopting a complicated tread change structure.

  The traveling crawler 25 shown in FIG. 42 is a narrow traveling crawler 25 that is set to be narrower than the left-right width dimension W1 of the standard traveling crawler 25. The left-right width dimension W3 of the narrow traveling crawler 25 is, for example, the left-right width dimension corresponding to the groove width of the ridge in the field. The tractor 10 having the narrow crawler travel crawler 25 attached to the rear crawler travel device 13 can smoothly travel between the ridges without breaking the corners of the heel G. In the traveling crawler 25 having a narrow width, the left and right width center line P of the engaged portion of the traveling crawler 25 is aligned with the left and right width center line Ca of the traveling crawler 25 itself. However, the point that the left and right width center lines Q of the driven wheels 21 and 23 and the rolling wheels 26 are offset from the left and right width center line P of the driving wheel body 16 by a predetermined width S on the inner side of the machine body is the standard specification or It is common with the traveling crawler 25 of the offset specification. The traveling crawler 25 shown in FIGS. 40 to 42 may be replaced according to the field situation and the work content.

  Next, another example of the front and rear link members 319 and 320 serving as a link mechanism will be described with reference to FIG. In the other example, the flange member 318 is detachably fastened and fixed to the rear axle case 14. A front link member 319 disposed on the front side of the rear axle 15 and a rear link member 320 disposed on the rear side of the rear axle 15 are provided. The track frame 17 is connected to the flange member 318 via the link members 319 and 320 so as to be swingable back and forth. That is, the flange member 318 (which can be said to be the traveling machine body 11), the pair of front and rear link members 319 and 320, and the track frame 17 form a four-bar link structure. The point which employ | adopts the said 4 node link structure is the same as that of previous embodiment. A significant difference from the previous embodiment is that each link member 319, 320 has a structure in which a pair of left and right link rods 319a, 319b, 320a, 320b are combined.

  As shown in FIG. 43, the flange member 318 in another example is made of a steel plate and a flat plate-shaped first bracket body 351, a steel plate and a flat plate-shaped second bracket body 352, and a steel plate and a flat plate-shaped third bracket. A body 353. The first and second bracket bodies 351, 352 are welded and fixed to the rear axle case 14 with their respective upper sides facing each other with an appropriate interval in the left-right direction.

  The third bracket body 353 is located further to the outer side of the machine body (the left and right outer sides) than the second bracket body 352. The third bracket body 353 and the second bracket body 352 are connected via a horizontally long connecting shaft body 341. A screw portion formed on one end side of the connecting shaft body 341 passes through the second bracket body 352 and is fastened with a nut. A screw portion formed on the other end side of the connecting shaft body 341 passes through the third bracket body 353 and is fastened with a nut. That is, the connecting shaft body 241 is attached to the second and third bracket bodies 352 and 353 in a doubly supported beam shape.

  Further, the third bracket body 353 and the first bracket body 351 are connected via a connecting shaft body 342 different from the previous connecting shaft body 341. A screw portion formed on one end side of the connecting shaft body 342 passes through the first bracket body 351 and is fastened with a nut. A screw portion formed on the other end side of the connecting shaft body 342 passes through the third bracket body 353 and is fastened with a nut. That is, the connecting shaft body 342 is attached to the first and third bracket bodies 351 and 353 in a doubly supported beam shape.

  The flange member 318 is provided with front and rear upper end pivot shafts 327 and 328. Front and rear upper end pivot shafts 327 and 328 are extended in parallel with the rear axle 15. Upper and lower boss portions of the front link member 319 and the rear link member 320 are rotatably supported on the front and rear upper pivot shafts 327 and 328. In this case, a pivoting shaft boss body 343 that pivotally supports the front and rear upper pivot shafts 327 and 328 is fixed between the third bracket body 353 and the first bracket body 351. With the upper and lower upper pivot shafts 327 and 328 passing through the upper boss portions 345 and 346 of the front and rear link members 319 and 320, one end of the front and rear upper pivot shafts 327 and 328 is connected to the pivot shaft boss. The body 343 is rotatably supported.

  The track frame 17 is provided with front and rear lower pivot shafts 330 and 331. A lower end side of the front link member 319 is rotatably connected to the track frame 17 by a front lower end pivot shaft 330. The front lower end pivot attachment shaft 330 is positioned in front of the front upper end pivot attachment shaft 327, and the front link member 319 is inclined and supported forward. Further, the lower end side of the rear link member 320 is rotatably connected to the track frame 17 by a rear lower end pivot shaft 331. The rear lower end pivot shaft 331 is positioned rearward of the rear upper pivot shaft 328, and the rear link member 320 is supported by being inclined rearward.

  The front and rear link members 319, 320 each have a pair of left and right link rods 319a, 319b, 320a, 320b. The upper sides of the link rods 319a and 319b of the front link member 319 are fixed to the upper end boss portion 345 in a state where they are opposed to each other with an appropriate interval in the left-right direction. An upper end side boss portion 345 is rotatably fitted to the front upper end pivot shaft 327. The lower side of the link rods 319a and 319b of the front link member 319 is opposed to a front lower end pivot shaft attached to a front bearing cylinder 77 provided on the upper surface of the track frame 17 in a state of being opposed to each other at an appropriate interval in the left-right direction. 330 are connected.

  On the other hand, the upper side of the link rods 320a and 320b of the rear link member 320 is fixed to the upper end side boss portion 346 in a state of being opposed to each other with an appropriate interval in the left-right direction. An upper end boss portion 346 is rotatably fitted on the rear upper end pivot shaft 328. The lower side of the link rods 320a and 320b of the rear link member 320 is pivotally attached to the rear bearing cylinder 77 provided on the upper surface of the track frame 17 in a state where the lower sides of the link rods 320a and 320b are opposed to each other with an appropriate interval in the left-right direction. It is connected via a shaft 331.

  Needless to say, the same effect as in the case of employing the link members 19 and 20 in the previous embodiment can be obtained even when configured as in the above-described another example. In addition, since each link member 319, 320 has a structure in which a pair of left and right link rods 319a, 319b, 320a, 320b are combined, for example, it is significantly more than when a metal link member such as casting is employed. Weight reduction can be achieved. Further, the assembly workability of the traveling crawler 25 can be improved.

8 Engine 11 Traveling machine body 12 Front wheel 15 Rear axle 17 Track frame 18 Flange member 19 Front link member 20 Rear link member 21 Front driven wheel body 23 Rear driven wheel body 25 Traveling crawler 26 Rolling wheel 27 Front upper end pivot shaft 28 Rear upper end Pivot shaft 30 front lower pivot shaft 31 rear lower pivot shaft 77 bearing cylinder

Claims (3)

A traveling machine body on which an engine is mounted and a track frame that is provided at a lower portion of the traveling machine body and supports a traveling crawler are wound, and the track frame can be swung back and forth through a link mechanism on the traveling machine body. A working vehicle installed,
The link mechanism is composed of a pair of front and rear link members, and the traveling machine body, the pair of front and rear link members, and the track frame form a four-bar link structure.
Work vehicle. A plurality of metal cores are equidistantly provided on the inner peripheral side of the traveling crawler, and a locking tooth body and a ring shape that are engaged with the metal core on the outer peripheral side of a driving wheel that drives the traveling crawler to circulate. Department and
A rubber belt body is provided on the inner peripheral side of the traveling crawler, and the traveling crawler is configured to rotate around when the ring-shaped portion of the driving wheel body contacts the rubber belt body.
The work vehicle according to claim 1. The track frame includes a driven wheel around which the traveling crawler is wound,
Furthermore, it has an extendable idler fork that supports the driven wheel body, and a tension spring that biases the driven wheel body on the inner peripheral side of the traveling crawler.
The work vehicle according to claim 1 or 2.

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