JP5844426B2 - Work vehicle - Google Patents

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

  However, in the configuration of the prior art, since the track frame is supported by the swinging fulcrum shaft at one point, the load is easily concentrated on the swinging fulcrum shaft, and the swinging fulcrum shaft is not deformed. There was a risk of causing malfunctions. In addition, when traveling forward or backward, the traveling crawler inclines forward or backward with respect to the swing fulcrum shaft portion when climbing over a convex portion such as a basket in the field, and the front / rear inclination angle of the ground contact surface of the traveling crawler Therefore, the height of the traveling machine body with respect to the ground is also likely to change, and there is a problem that it is not possible to maintain a good ride comfort for the operator who has boarded the control seat.

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

The invention of claim 1 includes a traveling machine body (11) on which an engine (8) is mounted, a track frame (17) disposed below the traveling machine body (11), a driving wheel body (16), and front and rear driven wheels. In a work vehicle comprising a body (21) (23) and a traveling crawler (25) mounted on the track frame (17) via a plurality of rolling wheels (26), a pair of front and rear is mounted on the traveling machine body (11). The track frame (17) is attached to be able to swing back and forth via link members (19) and (20), and the traveling body (11), the pair of front and rear link members (19) and (20), and the track frame (17). ) In a four-bar link structure, and the upper swing fulcrum of the pair of front and rear link members (19) and (20) is attached to the flange member (18) provided on the rear axle case (14) of the traveling body (11). Axis (2 ) (28) is pivotally supported, while the pair of front and rear link members (19) and (20) are pivotally supported by the lower swing fulcrum shafts (30) and (31) above the track frame, and the flange member (18). In addition, the upper swing fulcrum shafts (27) and (28) are sandwiched between the upper swing fulcrum shafts (27) and (28) so as to restrict the forward and backward rotation around the upper swing fulcrum shafts (27) and (28) of at least one of the link members (19) and (20). A pair of swing restricting stoppers (179) and (180) arranged as described above are provided .

  According to the present invention, a traveling machine body (11) equipped with an engine (8), a track frame (17) disposed at a lower portion of the traveling machine body (11), a driving wheel body (16), front and rear driven wheel bodies ( 21) In a work vehicle including a traveling crawler (25) attached to the track frame (17) via a plurality of rolling wheels (26) and a plurality of rolling wheels (26), a pair of front and rear link members are disposed on the traveling body (11). (19) The track frame (17) is attached to be able to swing back and forth via (19) and (20), and the traveling body (11), the pair of front and rear link members (19) and (20), and the track frame (17) are attached. A swing regulation that is configured in a four-bar link structure and that restricts the rotation of the traveling machine body (11) around the upper swing fulcrum shafts (27) and (28) of at least one of the link members (19) and (20). Stock (179) Since (180) is provided, the swing range of the at least one link member (19) (20) can be easily set, and swing control of the front and rear link members (19) (20) is restricted. There is an effect that it can be realized with a simple structure.

It is a side view of a tractor. It is a top view of a tractor. It is an enlarged side view of a crawler traveling device. It is side surface sectional drawing which shows the 1st example of a link member attachment structure. It is side surface sectional drawing which shows the 2nd example of a link member attachment structure. It is side surface sectional drawing which shows the 3rd example of a link member attachment structure. It is side surface sectional drawing which shows the 4th example of a link member attachment structure.

  Hereinafter, an embodiment 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 mission 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. One end side of the rear axle 15 is pivotally supported in the rear axle case 14, and then a reduction final gear (not shown) is pivotally supported on one end side 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 holding down a plurality of metal cores (not shown) embedded in the traveling crawler 25 at equal intervals. Fastened and fixed. A plurality of rolling wheels 26 and a crawler guide body are formed 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 of the inner peripheral surface of the traveling crawler 25. 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. In this case, a portion of the front lower end pivot shaft 30 that protrudes outward from the lower end side of the front link member 19 pivots to the upper end side boss portion of the front support column 171 erected on the upper front end side of the track frame 17. It is pivotally supported. That is, the lower end side boss portion of the front link member 19 and the upper end side boss portion of the front support column 171 are connected via the front lower end pivot shaft 30 so as to be rotatable. 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.

  Further, as shown in FIGS. 3 and 4, the lower end of the rear link member 20 is rotatably connected to the track frame 17 by a rear lower end pivot shaft 31. In this case, a portion of the rear lower end pivot shaft 31 that protrudes outward from the lower end side of the rear link member 20 rotates to the upper end side boss portion of the rear column 172 that is erected on the upper rear end side of the track frame 17. It is pivotally supported. In other words, the lower end side boss portion of the rear link member 20 and the upper end side boss portion of the rear support column 172 are connected via the rear lower end pivot shaft 31 so as to be rotatable. 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).

  As shown in FIGS. 3 and 4, the front and rear lower pivot shafts 30 and 31 are located in a region on the inner peripheral side of the traveling crawler 25 and on the outer peripheral side of the drive wheel body 16 in a side view of the tractor 10. . 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.

  The front and rear lower pivot shafts 30 and 31 are positioned in a region on the inner peripheral side of the traveling crawler 25 and on the outer peripheral side of the drive wheel body 16 in a side view of the tractor 10. For this reason, when viewed from the front and rear of the tractor 10 in the traveling direction, the front and rear lower pivot shafts 30 and 31 are disposed in the vicinity of the front and rear driven wheels 21 and 23 and the center of the plurality of rolling wheels 26 (near the center in the thickness direction). It is possible to place them close to each other. Therefore, the amount of offset in the left and right direction of the front and rear lower pivot shafts 30 and 31 can be reduced with respect to the load applied to the front and rear driven wheels 21 and 23 and the plurality of rolling wheels 26 (pushing pressure of the traveling crawler 25). There is an advantage that the support strength of the front and rear lower pivot shafts 30, 31 can be easily improved.

  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 body 11, the front link member 19 is tilted so that the inclination angle from the horizontal plane becomes small with the front upper end pivot shaft 27 as a fulcrum. Rotate. Further, the rear link member 20 is rotated 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 rear 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.

  When pitching (forward tilting operation) so that the front portion of the traveling machine body 11 is lowered, the front link member 19 is pivoted in a tilting direction with the front lower end pivot shaft 30 as a fulcrum so that the tilt angle from the horizontal plane is reduced. To do. 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 is increased 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.

  As shown in FIGS. 1 and 3, 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, a truck frame 17 provided on the lower rear side of the traveling machine body 11, The left and right traveling crawlers 25 are attached to the frame 17, the rear axle 15 transmits the rotational force to the traveling crawler 25, and the front and rear pivot shafts that pivotally support the track frame 17 on the traveling machine body 11. In the work vehicle 10 provided with the upper pivot shafts 27 and 28 spaced apart from each other, the front and rear upper pivot shafts 27 and 28 are disposed directly below the rear axle case 14 as an axle case on which the rear axle 15 is pivotally supported. The track frame 17 is connected to the rear axle case 14 via a front link member 19 and a rear link member 20 provided on the front and rear upper pivot shafts 27 and 28. Therefore, for example, when moving forward or backward, when traveling over a convex portion such as a farm shore, even if the traveling crawler 25 tilts forward or backward with the front and rear upper pivot shafts 27 and 28 as the center, The front / rear inclination angle of the ground contact surface of the traveling crawler 25 is smaller than that of the prior 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 FIG. 3, a swing fulcrum shaft is formed by the front and rear upper pivot shafts 27 and 28 and the front and lower lower pivot shafts 30 and 31, and the front and rear upper pivot shafts 27 and 28 are attached to the rear axle case 14. The front and rear lower pivot shafts 30, 31 are provided on the track frame 17, and the upper and lower link portions 20, 21 are coupled to the pivot shafts 27, 28, 30, 31 respectively. 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. Larger size 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. 1 and 3, 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, a truck frame 17 provided on the lower rear side of the traveling machine body 11, The crawler 25 includes left and right traveling crawlers 25 attached to the frame 17, a rear axle 15 that transmits rotational force to the traveling crawler 25, and a plurality of rolling wheels 26 provided on the track frame 17. In the work vehicle 10 that supports the grounding side of 25, the front upper end pivot shaft 27 and the rear upper end pivot shaft 28 as two upper pivot shafts provided immediately below the rear axle 15 and the track frame 17 are provided 2 Two link members 19, 20 are connected between the front lower pivot shaft 30 and the rear lower pivot shaft 31 as the lower pivot shaft of the book, and the two upper members are connected to the front and rear of the rear axle 15. Front top pivot 7 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 FIG. 3, the rear ground side of the traveling crawler 25 is supported on the track frame 17 via the rear driven wheel body 23, and the rolling wheel 26 and the rear driven wheel body 23 adjacent to the rear driven wheel body 23 are supported. The other of the two front lower pivot shafts 30 and the rear lower pivot shaft 31 is arranged 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. 3, 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 FIG. 3, 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 a traveling crawler 25 are provided. A work vehicle 10 to which the track frame 17 is attached so as to be able to swing back and forth via a link. The link mechanism is composed of a pair of front and rear link members 19 and 20, and the traveling machine body 11 and the pair of front and rear links. Since the members 19 and 20 and the track frame 17 have a four-bar link structure, the traveling machine body is separated from, for example, a ridge or a tall crop in the straddling work of the tractor 10 due to the presence of the four-bar link structure. 11 can be supported, and a sufficient space can be secured for a culm or a tall crop. In addition, while the structure can secure a sufficient space for a ridge or a tall crop, the forward and backward inclined posture of the traveling crawler 25 is prevented from changing greatly by the parallel link approximation operation of the four-bar link structure. it can. 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 first example of the front and rear link members 19 and 20 mounting structure will be described with reference to FIG. In each example of the mounting structure shown below, at least one of the front and rear link members 19 and 20 is configured such that one of the upper and lower pivot shafts 27, 28, 30, and 31 (swinging fulcrum shaft) can be changed in position. ing. Among these, the first example is a case in which the position of the upper end pivot shafts 27 and 28 can be changed in both the front and rear link members 19 and 20.

  Although detailed illustration is omitted, the flange member 18 is formed in a block shape by combining a plurality of bracket bodies and the like, and is detachably fixed to the bottom surface side of the rear axle case 14. In the first example, a plurality of front shaft support holes 177 are formed on the front side of the pair of left and right bracket bodies constituting the flange member 18 so as to jump along the arc direction with the front lower end pivot shaft 30 as the center. Has been. With the front upper end pivot shaft 27 penetrating through the upper end side boss of the front link member 19, both front ends of the front upper pivot shaft 27 are inserted into arbitrary front shaft support holes 177 corresponding in the left-right direction, A front upper end pivot shaft 27 is attached to both the left and right bracket bodies in the form of a double-supported beam. In this way, the mounting position of the front upper end pivot shaft 27 can be changed stepwise according to the position of the front shaft support hole 177.

  In addition, a plurality of rear shaft support holes 178 are formed on the rear side of the left and right bracket bodies so as to be lined up along the arc direction with the rear lower end pivot shaft 29 as the center. In a state where the rear upper end pivot shaft 28 is passed through the upper end side boss of the rear link member 20, both ends of the rear upper pivot shaft 28 are inserted into arbitrary rear shaft support holes 178 corresponding in the left-right direction, A rear upper end pivot shaft 28 is attached to both the left and right bracket bodies in the form of a double-supported beam. In this way, the mounting position of the rear upper end pivot shaft 28 can be changed stepwise according to the position of the rear shaft support hole 178.

  If comprised as mentioned above, if the attachment position (fulcrum position) of the rear upper end pivoting axis | shaft 28 in the rear link member 20 will be changed, the rocking | fluctuation behavior of the rear link member 20 at the time of tractor 10 advance will be changed. Moreover, if the attachment position of the front upper end pivot shaft 27 in the front link member 19 is changed, the swinging behavior of the front link member 19 when the tractor 10 moves backward is changed. Therefore, it is possible to easily obtain the swing behavior of the front and rear link members 19 and 20 appropriate for the work content of the tractor 10 and the field condition.

  Particularly in the first example, the front and rear upper end pivots are formed in the flange member 18 by forming a plurality of shaft support holes 177 and 178 along the arc direction around the front and lower lower pivots 30 and 31 whose positions cannot be changed. Since the mounting positions of the shafts 27 and 28 can be changed, the mounting positions of the front and rear upper pivot shafts 27 and 28 on the front and rear link members 19 and 20 are hardly changed without changing the shape (peripheral length) of the traveling crawler 25. Can change. Therefore, there is no need to perform a work that greatly changes the tension (tension) of the traveling crawler 25 due to the change in the attachment position of the front and rear upper pivot shafts 27 and 28. In the first example, the front and rear upper pivot shafts 27 and 28 of the front and rear link members 19 and 20 are repositioned. However, the present invention is not limited to this, and the front and lower lower pivot shafts 30 and 31 are positioned. It goes without saying that a configuration to be changed may be adopted.

  Next, a second example of the front and rear link member 19, 20 mounting structure will be described with reference to FIG. The second example is a case where only the rear upper end pivot shaft 28 of the rear link member 20 can be changed in position. In the second example, front and rear restricting pins 179 and 180 are provided on the flange member 18 as swing restricting stoppers for restricting front and rear rotation of the front link member 19 with the front upper end pivot shaft 27 as a fulcrum. A front regulating pin 179 is fixed in a doubly-supported beam shape between the left and right bracket bodies constituting the flange member 18 in front of the front upper end pivot shaft 27, and rearward from the front upper pivot shaft 27. The restriction pin 180 is fixed in a doubly supported beam shape. The range in which the lower end side of the front link member 19 rotates forward with the front upper end pivot shaft 27 as a fulcrum is defined by the front restriction pin 179. Similarly, the lower end side of the front link member 19 rotates backward with the front upper end pivot shaft 27 as a fulcrum. The moving range is defined by the rear regulating pin 180. The longitudinal movement of the traveling crawler 25 relative to the traveling machine body 11 is limited by the presence of the front and rear regulating pins 179 and 180.

  If comprised as mentioned above, the front-back rocking | fluctuation range of the front link member 19 (and also the front-back rocking | fluctuation range of the rear link member 20) which does not change the attachment position (fulcrum position) of the front upper end pivot shaft 27 can be set easily. The front and rear link members 19 and 20 can be controlled to swing back and forth with a simple structure. The arrangement and structure of the front and rear restricting pins 179 and 180 are not limited to the case of the second example, and may be applied to the rear upper end pivot shaft 28 of the rear link member 20 or the front and rear link members 19 and 20. You may apply to the lower end pivot attachment shafts 30 and 31.

  Next, a third example of the front and rear link member 19, 20 mounting structure will be described with reference to FIG. Similar to the first example, the third example is a case in which the upper end pivot shafts 27 and 28 of both the front and rear link members 19 and 20 are configured to be changeable. In the third example, a front long slot 181 is formed on the front side of the flange member 18 and extends along the arc direction with the front lower end pivot shaft 30 as the center. The front distal end side of the front upper end pivot shaft 27 penetrating the upper end side boss portion of the front link member 19 is inserted into the front long slot 181. A front upper long screw bolt 182 that extends upward and a front lower long screw bolt 183 that extends downward are fixed to a portion of the front upper end pivot shaft 27 that protrudes further left and right outward from the front long slot 181. Yes.

  The front upper plate piece 184 detachably mounted above the front long slot 181 in the flange member 18 is passed through the front upper long screw bolt 182, and the front upper plate piece 184 of the front upper long screw bolt 182 is passed through. A nut 185 is screwed on both sides of the pin. A front lower plate piece 186 that is detachably mounted below the front long slot 181 of the flange member 18 is passed through a front lower plate screw 183, and the front lower plate piece 186 of the front lower plate screw 183. Nuts 187 are screwed on both sides of the pin. In each of the plate pieces 184 and 186, the holes through which the long screw bolts 182 and 183 pass are loose fitting holes.

  After the nuts 185 and 187 sandwiching the plate pieces 184 and 186 are loosened, the mounting position of the front upper end pivot shaft 27 is adjusted along the front slot 181 and then the nuts 185 and 187 are tightened. The mounting position of the front upper end pivot shaft 27 is changed steplessly along the front long slot 181.

  As shown in FIG. 6, a rear long slot 191 is formed on the rear side of the flange member 18 and extends along the arc direction with the rear lower end pivot shaft 31 as the center. The outward leading end side of the rear upper end pivot shaft 28 that passes through the upper end side boss portion of the rear link member 20 is inserted into the rear elongated slot 191. A rear upper long screw bolt 192 that extends upward and a rear lower long screw bolt 193 that extends downward are fixed to a portion of the rear upper end pivot shaft 28 that protrudes further left and right outward from the rear long slot 191. Yes.

  The rear upper plate piece 194 detachably mounted above the rear long slot 191 in the flange member 18 is passed through the rear upper long screw bolt 192, and the rear upper plate piece 194 of the rear upper long screw bolt 192 is penetrated. A nut 195 is screwed on both sides of the pin. The rear lower plate piece 196 detachably mounted below the rear long slot 191 in the flange member 18 is passed through the rear lower long screw bolt 193, and the rear lower plate piece 196 of the rear lower long screw bolt 193 is inserted. Nuts 197 are screwed on both sides of the pin. In each plate piece 194, 196, the hole through which the long screw bolt 192, 193 passes is a loose fitting hole.

  After the nuts 195 and 197 sandwiching the plate pieces 194 and 196 are loosened, the mounting position of the rear upper end pivot shaft 28 is adjusted along the rear long slot 191 and then the nuts 195 and 197 are tightened. The mounting position of the rear upper end pivot shaft 28 is steplessly changed along the rear long slot 191.

  Also when comprised as mentioned above, there exists an effect that the rocking | fluctuation behavior of the front and rear link members 19 and 20 appropriate for the work content of the tractor 10 and the field condition can be easily obtained as in the first example. In addition, since the positions of the upper end pivot shafts 27 and 28 are changed along the corresponding long slots 181 and 191 respectively, the shape (peripheral length) of the traveling crawler 25 is almost the same as in the first example. Without changing, the mounting positions of the front and rear upper pivot shafts 27 and 28 on the front and rear link members 19 and 20 can be changed. There is no need to perform work that greatly changes the tension. In the third example, a configuration in which the positions of the front and rear lower pivot shafts 30 and 31 are changed may be adopted. In at least one of the front and rear link members 19, 20, one of the upper and lower pivot shafts 27, 28, 30, 31 may be configured to be changeable in position.

  Next, a fourth example of the front and rear link member 19, 20 mounting structure will be described with reference to FIG. As in the first and fourth examples, the fourth example is a case where the positions of the upper end pivot shafts 27 and 28 of both the front and rear link members 19 and 20 are changeable. The fourth example has a configuration that can be said to be a modification of the third example, and the upper and lower upper pivot shafts 27 passing through the upper bosses of the link members 19 and 20 in the long slot holes 181 and 191 formed in the flange member 18. , 28 is inserted through the outward leading end side. Parts of the front and rear upper pivot shafts 27 and 28 that protrude further outward in the left and right directions from the long slot holes 181 and 191 are piston rods of the front hydraulic cylinder 201 or the rear hydraulic cylinder 202 as actuators fixed to the flange member 18. It is connected to. The mounting positions of the front and rear upper pivot shafts 27 and 28 are adjusted along the elongated slots 181 and 191 by the expansion and contraction of the piston rods in the hydraulic cylinders 201 and 202, respectively.

  According to the above configuration, the mounting positions (fulcrum positions) of the front and rear upper pivot shafts 27 and 28 on the front and rear link members 19 and 20 can be easily changed by manual or automatic valve control for the hydraulic cylinders 201 and 202. Is possible. For example, when it is desired to change the mounting positions of the front and rear upper pivot shafts 27 and 28 during the operation, the mounting position can be easily changed by a simple operation by the operator. It is also possible to automatically change the mounting positions of the front and rear upper pivot shafts 27 and 28 in response to changes in the traction load. Also in the fourth example, a configuration in which the positions of the front and rear lower pivot shafts 30, 31 are changed by an actuator may be adopted.

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 (swing) Fulcrum shaft)
28 Rear upper pivot shaft (oscillating fulcrum shaft)
30 Front and lower pivot shaft (oscillating fulcrum shaft)
31 Rear bottom pivot shaft (oscillating fulcrum shaft)
179,180 Restriction pin (swing restriction stopper)
201, 202 Hydraulic cylinder (actuator)

Claims (1)

A traveling machine body (11) equipped with an engine (8), a track frame (17) disposed at the lower part of the traveling machine body (11), a driving wheel body (16), front and rear driven wheel bodies (21) (23) And a traveling crawler (25) attached to the track frame (17) via a plurality of rolling wheels (26),
The track frame (17) is attached to the traveling machine body (11) through a pair of front and rear link members (19) and (20) so as to be able to swing back and forth.
The traveling machine body (11), the pair of front and rear link members (19) and (20) and the track frame (17) are configured in a four-bar link structure,
The upper swing fulcrum shafts (27) and (28) of the pair of front and rear link members (19) and (20) are pivotally supported on the flange member (18) provided on the rear axle case (14) of the traveling machine body (11). On the other hand, the lower swing fulcrum shafts (30) and (31) of the pair of front and rear link members (19) and (20) are pivotally supported above the track frame,
The upper swing fulcrum shaft (27) is restricted to the flange member (18) so as to restrict the forward and backward rotation of the at least one link member (19) (20) around the upper swing fulcrum shaft (27) (28). ) (28) is provided with a pair of swing restricting stoppers (179) and (180) disposed therebetween.
Work vehicle.

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