JP2010202057A - Semi-crawler type working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semi-crawler type working vehicle capable of smoothly oscillating a truck frame while preventing the sinking of a driven wheel at a front side. <P>SOLUTION: A crawler 15 of the semi-crawler type tractor includes an output shaft 71, a rear axle housing, the truck frame 46, an oscillation frame 45 and a tension spring 95. The oscillation frame 45 is fixed to the truck frame 46 and rotatably mounted to the rear axle housing, and thereby the oscillation frame supports the truck frame 46 so as to be oscillated. The tension spring 95 has one end connected to the oscillation frame 45 and the other end connected to a machine body side, and can apply a force to move a front side of the truck frame 46 upward. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a semi-crawler type work vehicle, and more particularly to a swingable track frame.

  2. Description of the Related Art Conventionally, in a semi-crawler type work vehicle in which a wheel is disposed on the front side and a crawler unit is disposed on the rear side, a configuration in which the crawler unit is formed in a substantially triangular shape that protrudes upward in a side view is known. Such a crawler unit may be configured as follows. A driving wheel for driving the crawler portion is arranged at the upper vertex of the triangle, and two driven wheels are arranged at the remaining lower vertex. Then, two driven wheels are supported on the swingable track frame. There exists patent document 1 as what discloses this kind of crawler part.

JP 2001-239968 A

  In a vehicle having a crawler portion, it is preferable to make the contact area of the crawler portion as large as possible from the viewpoint of improving traction force and preventing the crawler portion from sinking. In a semi-crawler type work vehicle such as a tractor, in order to avoid interference with a work machine connected to a rear portion, a track frame is extended forward to increase a ground contact area.

  However, when the track frame is extended to the front side, the distance from the swing center to the front driven wheel becomes longer, and the own weight of the crawler portion acts on the front driven wheel in a biased manner. For this reason, there is a risk that the front side of the bottom of the crawler portion may sink, especially in soft ground such as wetlands.

  In this regard, in the conventional configuration as shown in Patent Document 1, the contact position between the front driven wheel and the crawler belt is greater than the contact position between the wheel and the crawler belt arranged in the middle of the track frame. By arranging the driven wheel so as to be on the upper side, the bottom of the crawler portion is prevented from sinking. However, in this configuration, the crawler belt at the front part of the bottom of the crawler part is in a state of being lifted from the ground, so that the ground contact area is reduced accordingly.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a semi-crawler type work vehicle capable of smoothly swinging a track frame while preventing a front driven wheel from sinking. It is in.

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to an aspect of the present invention, the following configuration is provided in a semi-crawler type work vehicle including a wheel disposed on the front side of the airframe and a crawler portion disposed on the rear side. That is, the semi-crawler type work vehicle includes a drive wheel, a front driven wheel, a rear driven wheel, a crawler belt, an output shaft, a housing, a track frame, a swing frame, and an elastic member. The driving wheel is rotated by the driving force of the engine. The front driven wheel is disposed below the drive wheel and on the front side of the drive wheel. The rear driven wheel is disposed below the drive wheel and behind the drive wheel. The crawler belt is wound around the driving wheel, the front driven wheel, and the rear driven wheel. The output shaft is connected to the drive wheel. The housing covers at least a part of the output shaft on the center side of the body from the drive wheel. The track frame supports the front driven wheel and the rear driven wheel. The swing frame is fixed to the track frame and is rotatably attached to the housing, thereby supporting the track frame so as to be swingable. One end of the elastic member is connected to the swing frame or the track frame, and the other end is connected to the body side, so that a force for moving the front side of the track frame upward can be applied. .

  As a result, the elastic member exerts a force so that the front side of the track frame moves upward, so that the sinking of the bottom front side of the crawler portion can be effectively prevented. In this way, since excessive sinking of the front side of the bottom of the crawler portion can be prevented, stable traveling of the semi-crawler type work vehicle can be realized.

  In the semi-crawler type work vehicle, the elastic member is preferably a tension spring.

  Thereby, the structure for applying the force which moves the front side of a track frame upward can be simplified by using a tension spring.

  The semi-crawler type work vehicle is preferably configured as follows. A frame-side holder for attaching one end of the elastic member to the swing frame or the track frame. The said frame side holder is comprised so that the attachment position of the said elastic member can be changed.

  Thereby, the force which acts on a track frame or a rocking | fluctuation frame by an elastic member can be changed by changing an attachment position. Therefore, a force according to the environment in which the semi-crawler type work vehicle travels and the type of work can be applied to the track frame, and the work using the semi-crawler type work vehicle can be performed more efficiently.

The side view which showed the semi-crawler type tractor which concerns on one Embodiment of this invention. The partial back sectional view which showed the structure for driving a crawler part roughly. The side surface partial sectional view of the crawler part which showed the principal part of the rocking | fluctuation frame of a track frame. Side surface partial sectional drawing which showed a mode when the front side regulation bolt is contacting the regulation plate. The expanded side view which showed the structure of the frame side holder holding a spring in a modification.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view showing a semi-crawler tractor 10 according to an embodiment of the present invention. In the following description, “left side”, “right side” and the like simply mean the left side and the right side in the direction in which the semi-crawler tractor 10 moves forward.

  A semi-crawler type tractor 10 as a semi-crawler type work vehicle for agricultural work shown in FIG. 1 is configured so that various devices such as a plow, a harrow, a loader and the like can be mounted as necessary to perform various types of work. Yes. A front wheel 14 is disposed at the front portion of the semi-crawler tractor 10, and a crawler portion 15 is disposed at the rear portion. A bonnet 20 that can be opened and closed is disposed at the front of the semi-crawler tractor 10 and above the front wheel 14.

  An engine 19 is accommodated in the bonnet 20. The engine 19 is supported by a frame (not shown) included in the semi-crawler tractor 10 directly or via a vibration isolation member.

  A cabin 16 that constitutes a driving space is disposed behind the hood 20, and an operation unit and a seat unit (not shown) for performing various operations are provided inside the cabin 16. . An operator of the semi-crawler tractor 10 can perform a traveling operation of the semi-crawler tractor 10 through the operation unit.

  The engine 19 has a crankshaft extending in the front-rear direction. A flywheel (not shown) is fixed to the rear end of the crankshaft, and the rotation of the flywheel is transmitted to a mission case (not shown) via a clutch and a shaft. The power of the engine 19 is appropriately shifted in the transmission case and then transmitted to the rear axle device 70 to drive the crawler unit 15.

  Further, in the semi-crawler type tractor 10 of the present embodiment, a connecting device 90 is disposed at the rear part of the machine body, and the connecting device 90 is configured to be able to connect various working machines such as the above-described plow and halo. .

  Next, the configuration of the crawler unit 15 and the vicinity thereof will be described. FIG. 2 is a partial rear cross-sectional view schematically showing a configuration for driving the crawler unit 15. FIG. 3 is a partial cross-sectional side view of the crawler unit 15 showing the main part of the swing frame 45 of the track frame 46. FIG. 4 is a partial cross-sectional side view illustrating a state where the front side regulation bolt 92 is in contact with the regulation plate 91. In FIGS. 2 to 4, some components are not shown in order to prevent the contents of the drawings from becoming complicated.

  In the rear axle device 70, a pair of left and right output shafts (rear axles) 71 are disposed so as to extend in the left-right direction of the body. The output shaft 71 is supported in a rear axle housing 72 as a housing via a bearing, and a crawler portion 15 is connected to an outer end portion thereof.

  Further, the rear axle housing 72 is supported on the machine body side via the square pipe 65 in the vicinity of the crawler portion 15. More specifically, the square pipe 65 is attached to the cabin 16 via a vibration isolation member. An upper plate 66 disposed on the upper surface of the rear axle housing 72 is fixed to the square pipe 65. A lower plate 67 is disposed on the lower surface of the rear axle housing 72. The upper plate 66 and the lower plate 67 are vertically moved by a plurality of connecting bolts 68 with the rear axle housing 72 sandwiched in the vertical direction. It is connected.

  The crawler unit 15 includes a crawler belt 51, a drive sprocket (drive wheel) 52, a wheel 80, a front idler (front driven wheel) 84, a rear idler (rear driven wheel) 85, and a swing frame 45. And a track frame 46 and a spring (elastic member) 95 as main components.

  The crawler belt 51 is configured to be endless, and is wound around the drive sprocket 52, the front idler 84, the rear idler 85, and the wheel 80. As a result, as shown in FIG. 3, the crawler belt 51 has a substantially triangular shape with the driving sprocket 52, the front idler 84, and the rear idler 85 as three apexes in a side view. The drive sprocket 52 is disposed at a high position, while the front idler 84 and the rear idler 85 are disposed at positions close to the ground. Further, the front idler 84 is disposed in front of the drive sprocket 52 and the rear idler 85 is disposed behind the drive sprocket 52 in plan view. Further, the crawler unit 15 of the present embodiment is configured so that the distance from the swing center to the front idler 84 is longer than the distance from the swing center to the rear idler 85 of the track frame 46. A rear idler 85 is arranged.

  The configuration of the drive sprocket 52 will be described. The drive sprocket 52 is for driving the crawler belt 51 by a driving force transmitted from the engine 19 side via the transmission case and the rear axle device 70. The drive sprocket 52 of this embodiment is of a pin drive type, and includes a disk 31, a pin support plate 33, and a drive pin 34 as main components.

  The disk 31 is configured as a disk-like member having a through-hole support hole 36 formed in the center. A disk portion cylinder portion 37 for attaching the pin support plate 33 is integrally formed on the outer peripheral portion of the disk 31.

  The pin support plates 33 and 33 are formed as a pair, and each is formed in a ring plate shape. These pin support plates 33 and 33 are arranged in a pair so as to sandwich the disk part cylinder part 37 in the axial direction, and are fixed to the end surface of the disk part cylinder part 37 by appropriate means such as bolts.

  The space on the outer side in the radial direction of the disk portion cylinder portion 37 is partitioned by pin support plates 33 and 33, whereby an annular groove 38 is formed in the outer peripheral portion of the drive sprocket 52 (the portion between the pin support plates 33 and 33). Is formed. In the annular groove 38, a fitting tooth 35 described later formed on the inner peripheral portion of the crawler belt 51 can be inserted from the outside.

  The drive pins 34 are arranged at equal intervals in the circumferential direction inside the annular groove 38 formed in the drive sprocket 52. Each drive pin 34 is fixed between two pin support plates 33, 33.

  On the other hand, on the inner peripheral surface of the endless crawler belt 51, a plurality of fitting teeth 35 formed in a convex shape are arranged at predetermined intervals in the longitudinal direction of the crawler belt 51. By inserting the fitting teeth 35 between the driving pins 34, the driving sprocket 52 and the crawler belt 51 are fitted, and the driving force of the driving sprocket 52 can be transmitted to the crawler belt 51.

  As shown in FIG. 2, the disk 31 has a shape in which a portion connecting the central part where the support hole 36 is formed and the outer disk part cylinder part 37 is slightly curved. Therefore, in the drive sprocket 52, the annular groove 38 (drive pin 34) is disposed at a position offset from the position of the support hole 36 by a predetermined distance to the outside (one side in the axial direction).

  The distal end of the output shaft 71 protrudes from the rear axle housing 72, and a disk fixing portion 73 is integrally formed at the end thereof. The disk fixing portion 73 is configured as a stepped flange having a small diameter portion and a large diameter portion, and the small diameter portion is inserted into a support hole 36 formed in the disk 31 of the drive sprocket 52. On the other hand, the large-diameter portion is fixed to the surface on one side in the axial direction of the disk 31 via a plurality of bolts 41.

  A disk fixing member 61 is fixed to the surface of the disk 31 opposite to the side on which the output shaft 71 is attached. The disc fixing member 61 includes a flange portion 62 that is fixed to the disc 31 and a support shaft 64 that is formed so as to protrude from the center portion of the flange portion 62.

  The flange portion 62 is fixed to the center portion of the disk 31 by the bolt 41. With this configuration, the flange portion 62 of the disc fixing member 61, the disc 31, and the disc fixing portion 73 of the output shaft 71 are fixed by the plurality of bolts 41. Accordingly, the drive sprocket 52 and the disk fixing member 61 are attached so as to rotate integrally with the output shaft 71. The support shaft 64 of the disk fixing member 61, the disk 31 (drive sprocket 52), and the output shaft 71 are arranged with their axes aligned with each other. The support shaft 64 functions as a support mechanism for supporting a swing frame 45 described later.

  Next, the swing frame 45 will be described. The swing frame 45 is for supporting the track frame 46 so as to be swingable, and includes an outer frame 75, a machine body side frame 76, and two connecting rods 77 as main components.

  As shown in FIGS. 1 and 2, the outer frame 75 has an arm portion 79 and a mounting portion 78. The arm portion 79 is configured in a curved shape such that the U-shape is turned upside down in a side view. As shown in FIGS. 2 and 3, the outer end portions of the connecting rod 77 are fixed to the two end portions located below the arm portion 79. The attachment portion 78 is attached to the upper portion of the arm portion 79 and attached to the support shaft 64. The support shaft 64 is connected to the attachment portion 78 via a bearing (not shown) built in the attachment portion 78, and the attachment portion 78 is rotatably supported by the support shaft 64. As described above, the outer frame 75 is supported in a suspended manner by the support shaft 64.

  The machine body side frame 76 includes a rotating portion 81, a connecting rod connecting frame 82, and a connecting plate 83.

  As shown in FIGS. 2 and 3, the rotating portion 81 has a cylindrical portion 55 and a flat plate portion 56, and the cylindrical portion 55 is fixed to a ring member 86 fixed to the outer end portion of the rear axle housing 72. The rotation part 81 can be rotated by being rotatably attached. In a state in which the rotating part 81 is attached to the ring member 86, a slight gap is formed between the rotating part 81 (cylinder part 55) and the ring member 86, and the grease applied to this gap causes the ring to The rotation of the rotating part 81 with respect to the member 86 is smooth.

  The connecting plate 83 is configured as a rectangular plate-like member, and is fixed to the flat plate portion 56 of the rotating portion 81. Two projecting walls 94 are formed on the surface of the connecting plate 83 on the machine body side. The protruding wall 94 holds a front regulating bolt 92 and a rear regulating bolt 93 (details will be described later) for regulating the swing angle range of the track frame 46. The connecting rod connecting frame 82 is formed of an elongated plate-like member, and is fixed to the connecting plate 83 with its longitudinal direction facing the front-rear direction. The connecting rod connecting frame 82 is connected to the connecting rod 77 at two locations.

  The track frame 46 is formed in a rectangular bar shape extending in the front-rear direction, and supports the front idler 84, the rear idler 85, and the plurality of rolling wheels 80. The front idler 84 is attached to the front portion of the track frame 46 and is disposed inside the front portion of the crawler belt 51. On the other hand, the rear idler 85 is attached to the rear end of the track frame 46. A plurality of wheels 80 are arranged in parallel between the front idler 84 and the rear idler 85 and below the track frame 46.

  The track frame 46 is fixed to the swing frame 45 via two connecting rods 77. As described above, the swing frame 45 of this embodiment is supported on both sides in the axial direction (two points of the support shaft 64 and the rear axle housing 72) with the drive sprocket 52 interposed therebetween, and the axis of the output shaft 71 is centered. Is configured to be rotatable. That is, the swing frame 45 is fixed to the track frame 46 and is rotatably attached to the support shaft 64 and the rear axle housing 72, thereby supporting the track frame 46 so as to be swingable. . As a result, the track frame 46 is supported by the swing frame 45 attached at two locations of the support shaft 64 and the rear axle housing 72, so that, for example, the load applied to the swing frame 45 is dispersed by the weight of the machine body. can do. Further, since the swing frame 45 is rotatably supported at two locations, the occurrence of shaft misalignment can be suppressed, and the swing of the track frame 46 can be made smooth.

  In addition, since the swing center of the track frame 46 is located on the axis of the output shaft 71, it is possible to ensure a large swinging width as compared with the configuration in which the swing center is disposed below the rear axle housing 72. It has become.

  The tension spring (elastic member) 95 is for preventing the front side of the bottom of the crawler portion 15 from sinking into the ground. Both ends of the tension spring 95 are each formed in a hook shape. As shown in FIG. 3, one end of the tension spring 95 is locked to a machine body side holder 96 fixed to the lower plate 67 via a bracket, and the other end is disposed on the front side of the connecting rod connection frame 82. The frame side holder 97 is locked.

  Next, a regulation mechanism for regulating the swing range of the track frame 46 will be described. This restriction mechanism includes a restriction plate 91, a front restriction bolt 92, and a rear restriction bolt 93 as main components.

  The restriction plate 91 is fixed to the lower plate 67. As shown in FIG. 3, the width of the regulation plate 91 becomes narrower toward the lower side in a side view. Although not shown in detail, the restriction plate 91 is formed by bending a plate-like member, and has a cross-sectional shape similar to that of C-shaped steel when cut along a horizontal plane.

  Two projecting walls 94 elongated in the vertical direction are formed on the surface of the connecting plate 83 on the machine body side in the vertical direction with a predetermined interval in the front-rear direction. A screw hole (not shown) for supporting the front regulating bolt 92 is formed in the front protruding wall 94, and a screw hole for supporting the rear regulating bolt 93 is formed in the rear protruding wall 94. Is formed. The front side regulation bolt 92 and the rear side regulation bolt 93 are fixed to the machine body side frame 76 (the swing frame 45) by being screwed into the screw holes.

  As shown in FIG. 3, the front restriction bolt 92 is disposed on the front side of the restriction plate 91, and the rear restriction bolt 93 is disposed on the rear side of the restriction plate 91. As shown in FIG. 4, when the track frame 46 is about to move to the rear side, the head of the front restriction bolt 92 contacts the front side of the restriction plate 91, and the movement of the track frame 46 is restricted. On the contrary, when the track frame 46 is about to move to the front side, the head of the rear side regulation bolt 93 comes into contact with the rear surface side of the regulation plate 91, and the movement of the track frame 46 is regulated.

  Moreover, the position of the front side regulation bolt 92 or the rear side regulation bolt 93 with respect to the protruding wall 94 can be changed by screw-moving the front side regulation bolt 92 and the rear side regulation bolt 93. As described above, the regulation mechanism of the present embodiment adjusts the swing angle (swing range) of the track frame 46 by adjusting the positions of the front regulation bolt 92 and the rear regulation bolt 93 with respect to the swing frame 45. Has the function to perform.

  Furthermore, in the configuration of the present embodiment, the tension spring 95 pulls the front part of the swing frame 45 that supports the track frame 46 upward, so that at least a part of the weight of the crawler part 15 biased to the front side is obtained. Acts to cancel. Therefore, even on a soft ground such as a wetland, it is possible to effectively prevent the crawler belt 51 (the front side of the bottom of the crawler unit 15) from sinking in a portion in contact with the front idler 84.

  As described above, the semi-crawler tractor 10 of the present embodiment is configured as follows. That is, the semi-crawler tractor 10 includes a drive sprocket 52, a front idler 84, a rear idler 85, a crawler belt 51, an output shaft 71, a rear axle housing 72, a track frame 46, and a swing frame 45. And a tension spring 95. The drive sprocket 52 is rotated by the driving force of the engine 19. The front idler 84 is disposed below the drive sprocket 52 and on the front side of the drive sprocket 52. The rear idler 85 is disposed below the drive sprocket 52 and behind the drive sprocket 52. The crawler belt 51 is wound around the drive sprocket 52, the front idler 84, and the rear idler 85. The output shaft 71 is connected to the drive sprocket 52. The rear axle housing 72 covers the output shaft 71 on the center side of the machine body from the drive sprocket 52. The track frame 46 supports the front idler 84 and the rear idler 85. The swing frame 45 is fixed to the track frame 46 and is rotatably attached to the rear axle housing 72, thereby supporting the track frame 46 so as to be swingable. One end of the tension spring 95 is connected to the swing frame 45 and the other end is connected to the machine body side, and a force that moves the front side of the track frame 46 upward can be applied.

  Thereby, since the front portion of the track frame 46 is pulled upward by the elastic force of the tension spring 95, the bottom of the crawler portion 15 can be effectively prevented from sinking. In this way, the track frame 46 can be smoothly swung to improve the followability of the crawler unit 15 with respect to the ground, and the bottom front side of the crawler unit 15 can be prevented from sinking, so that the semi-crawler tractor 10 can be stably driven. it can. This is particularly effective in a configuration in which the front side of the track frame 46 is easily lowered by disposing the front idler 84 away from the swing center as compared with the rear idler 85 as in the present embodiment.

  In the semi-crawler type tractor 10 of the present embodiment, the elastic member is constituted by a tension spring 95.

  Thereby, by using the tension spring 95, a configuration for applying a force for moving the front side of the track frame 46 upward can be simplified.

  Further, the semi-crawler tractor 10 of the present embodiment is also configured as follows. That is, the semi-crawler tractor 10 includes a regulation plate 91, a front regulation bolt 92, and a rear regulation bolt 93. The restriction plate 91 is attached to the body side. The front regulation bolt 92 is attached to the swing frame 45 and regulates the movement of the track frame 46 to the rear side by contacting the front side of the regulation plate 91. The rear side regulation bolt 93 is attached to the swing frame 45 and regulates the movement of the track frame 46 to the front side by contacting the rear side of the regulation plate 91.

  Thereby, a simple configuration for regulating the swing range of the track frame 46 can be realized.

  Further, the semi-crawler tractor 10 of the present embodiment is also configured to have an adjustment mechanism that can adjust the position of at least one of the front side regulation bolt 92 and the rear side regulation bolt 93.

  Accordingly, the swing restriction range of the track frame 46 can be changed by the adjustment mechanism in accordance with the environment in which the semi-crawler tractor 10 travels and the type of work. As a result, the work by the semi-crawler tractor 10 can be stabilized and the burden on the operator can be reduced. For example, when traveling on a wetland, the track frame 46 may be pivoted and fitted into the ground by adjusting the front side regulation bolt 92 and the rear side regulation bolt 93 so that the swing range is reduced. Can avoid the situation. In addition, when traveling on a relatively hard ground, by setting a large swing range, the followability of the crawler unit with respect to the ground can be improved and stable traveling can be realized.

  In addition to the configuration of the above-described embodiment, the configuration can be changed to a configuration in which a plurality of frame-side holders that connect the lower end of the tension spring 95 are arranged. Next, a modification will be described with reference to FIG. FIG. 5 is an enlarged side view showing the configuration of the frame side holder 197 that holds the tension spring 95 in the modified example. In addition, in this modification, since it is the same as that of the said embodiment about structures other than the frame side holder 197 connected to the lower end part of the tension spring 95, description of another structure is abbreviate | omitted.

  As shown in FIG. 5, in this modification, a plurality of frame side holders 197 for connecting the lower side of the tension spring 95 are arranged in the front-rear direction. On the other hand, the attachment position of the upper tension spring 95 is fixed. With this configuration, by selecting the frame side holder 197 at an appropriate position from among the plurality of frame side holders 197 according to the situation and connecting the tension spring 95, the upper attachment position to the lower attachment position. Thus, the force for lifting the front side of the track frame 46 upward can be changed. In this configuration, as the attachment position of the tension spring 95 is set to the front side, the force for pulling the front side of the track frame 46 upward increases, which is suitable for work on a soft ground such as a wetland.

  As described above, the modified semi-crawler tractor 10 is configured as follows. A frame-side holder 197 for attaching one end (lower end) of the tension spring 95 to the swing frame 45 is provided. The frame side holder 197 is configured so that the attachment position of the tension spring 95 can be changed.

  Thus, the force acting on the swing frame 45 by the tension spring 95 can be changed by changing the mounting position. Therefore, a force according to the environment in which the semi-crawler tractor 10 travels and the type of work can be applied to the swing frame 45, and work using the semi-crawler tractor 10 can be performed more efficiently.

  Although the embodiment of the present invention has been described above, the above configuration can be further modified as follows.

  Further, the elastic member for preventing the crawler unit 15 from sinking can be variously changed as long as the elastic force is applied to move the front side of the track frame 46 upward. For example, instead of a tension spring, a configuration in which the track frame 46 is prevented from being lowered forward by pressing the rear side of the track frame 46 downward with a compression spring can be used. Alternatively, the same effect can be exhibited even if a torsion coil spring or the like is used.

  Further, a damper for imparting resistance to the rotation of the swing frame 45 (track frame 46) can be added to the configuration of the above embodiment. For example, the damper may be arranged in parallel next to the tension spring 95 or provided inside the coil portion of the tension spring 95.

  The frame-side holder 97 (frame-side holder 197) of the above-described embodiment and modification is configured to be disposed on the swing frame 45, but can be changed to a configuration disposed on the track frame 46. In the above modification, the frame-side holder 197 at an appropriate position is selected from a plurality of frame-side holders 197 and the attachment position of the tension spring 95 is changed. Can be changed. For example, the frame side holder can be configured to be movable, and the attachment position of the tension spring 95 can be changed, or the frame side holder can be provided with an attachment position adjusting mechanism for changing the attachment position.

  Moreover, in the said embodiment, although the rocking | fluctuation frame 45 is the structure supported by two places, the support shaft 64 and the rear axle housing 72, this structure can be changed suitably. For example, the support shaft 64 may be omitted, and the swing frame 45 may be rotatably supported at one location of the rear axle housing 72.

  The restriction mechanism for restricting the swing range of the track frame 46 is not limited to the mechanism using the front restriction bolt 92 and the rear restriction bolt 93. For example, the contact member can be fixed to the front and rear projecting walls 94 via spacers, and the contact member can come into contact with the regulating plate 91 to change the swing range. In this case, the swing range can be adjusted by changing the spacer to one having a different size.

  In the above-described embodiment, the drive sprocket 52 is a pin drive type, but can be replaced with a sprocket having a shape having external teeth, for example.

14 front wheel 15 crawler part 45 swing frame 46 track frame 51 crawler belt 52 drive sprocket (drive wheel)
71 Output shaft 72 Rear axle housing (housing)
84 Front idler (front driven wheel)
85 Rear idler (rear driven wheel)
95 Tension spring (elastic member)
197 Frame side holder

Claims (3)

In a semi-crawler type work vehicle comprising a wheel disposed on the front side of the airframe and a crawler portion disposed on the rear side,
Driving wheels that rotate by the driving force of the engine;
A front driven wheel disposed below the drive wheel and on the front side of the drive wheel;
A rear driven wheel disposed below the drive wheel and on the rear side of the drive wheel;
A crawler belt wound around the drive wheel, the front driven wheel, and the rear driven wheel;
An output shaft connected to the drive wheel;
A housing that covers at least a part of the output shaft on the center side of the airframe from the drive wheel;
A track frame that supports the front driven wheel and the rear driven wheel;
A swing frame that is fixed to the track frame and rotatably mounted on the housing, thereby supporting the track frame so as to be swingable.
One end is connected to the swing frame or the track frame, the other end is connected to the machine body side, and an elastic member capable of acting a force to move the front side of the track frame upward,
A semi-crawler-type work vehicle comprising: The semi-crawler type work vehicle according to claim 1,
The semi-crawler type work vehicle, wherein the elastic member is a tension spring. The semi-crawler type work vehicle according to claim 1 or 2,
A frame side holder for attaching one end of the elastic member to the swing frame or the track frame;
The semi-crawler type work vehicle, wherein the frame-side holder is configured to be able to change a mounting position of the elastic member.

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