JP2011173569A - Working vehicle - Google Patents

Abstract

An object of the present invention is a work vehicle in which a posture of a track frame relative to a body frame is changed by a pair of front and rear swing arms, while the amount of forward and backward movement of the track frame to be moved up and down with respect to the body frame is reduced. Set the descent limit low.
A free end portion of a front swing arm 18a is connected to an upper end portion of a connection support 21 projecting upward from the front end portion of a track frame 12 by a connection pin 21a. The connecting pin 21a is located on a vertical line Z passing through the rotation axis P of the second grounding wheel 8b in a side view of the machine body. In a state where the track frame 12 is operated to the upper limit with respect to the airframe frame 11, the size of the distance D1 between the pin shaft core 21c of the connecting pin 21a and the upper end surface 12c of the track frame 12 in the vertical direction of the airframe is The distance between the axis 21c and the swing axis 18a of the swing arm 18a is greater than or equal to the distance D2 in the vertical direction of the machine body.
[Selection] Figure 3

Description

  The present invention relates to a drive sprocket that is rotatably supported by a machine frame, a plurality of grounding wheels that are rotatably supported side by side on the track frame, and a crawler tension ring that is supported at the rear of the track frame. The present invention relates to a work vehicle having a traveling device provided with a crawler belt wound around the drive sprocket, the plurality of grounded rollers and the crawler tension ring.

Conventionally, for example, Patent Document 1 discloses a work vehicle described above.
The one described in Patent Document 1 includes a pair of front and rear support arms (corresponding to a swing arm) connected to the machine frame so as to be swingable up and down, and the front support arm of the pair of front and rear support arms. Of the pair of front and rear support arms, the free end side of the rear support arm is connected to the track frame via a cancel link, and the pair of front and rear support arms are operated to swing. As a result, the posture of the track frame with respect to the ground frame is changed, and the posture of the body frame with respect to the ground can be changed, such as raising and lowering the aircraft frame with respect to the ground.

JP 9-193850 A

  When the work vehicle stops from traveling forward, a grounding reaction force larger than a grounding reaction force applied to the grounding wheel supported at the rear end portion of the track frame is applied to the grounding wheel supported at the front end portion of the track frame. For example, in a combine, when traveling over a heel, a large grounding reaction force is applied to the grounding wheel supported by the front end portion of the track frame. Therefore, in order to enable the change of the posture of the track frame with respect to the body frame by the pair of front and rear swing arms that are connected to the body frame so as to freely swing up and down, the front swing arm has a plurality of ground contacts among the track frames. If it is configured to support and act on the part where the second grounding wheel adjacent to the first grounding wheel located on the most front side of the wheel is connected, or the vicinity thereof, Even when a large ground reaction force is applied to the grounding wheel supported at the front end portion of the track frame, such as when it exceeds, the track frame can be advantageously supported.

However, when the configuration in which the free end portion of the front swing arm is directly connected to the track frame is employed, the free end side of the front swing arm is not directly connected to the track frame, but is provided on the track frame. Even if it is connected to the bracket, the following problem tends to occur when the connection is adopted at a location very close to the track frame.
The lower the lowering position of the track frame that is lowered with respect to the body frame by the lowering swing of the swing arm with respect to the body frame, the closer the front swing arm is to the vertical posture in the state where the track frame is lowered to the lower limit. As the track frame is moved up and down by the swing arm, the amount of forward and backward movement of the track frame with respect to the body frame increases, and the amount of forward and backward movement of the grounding wheel with respect to the body frame increases. In other words, the amount of forward and backward movement of the ground contact portion of the crawler belt with respect to the machine frame is large.

  The object of the present invention is to change the attitude of the track frame with respect to the fuselage frame by a pair of front and rear swing arms, while keeping the amount of forward and backward movement of the track frame to be raised and lowered relative to the fuselage frame small. An object of the present invention is to provide a work vehicle in which the lowering limit of the frame can be set low.

The first aspect of the present invention is a drive sprocket that is supported by a machine frame so as to be freely rotatable, a plurality of grounded wheels that are rotatably supported by being arranged in the longitudinal direction of the machine frame, and a crawler that is supported by a rear portion of the track frame. In a work vehicle having a traveling device provided with a tensioning wheel, a crawler belt wound around the driving sprocket, the plurality of grounding wheels, and the crawler tensioning wheel,
Of the pair of front and rear swing arms connected to the body frame so as to freely swing up and down, a connecting support projecting upward from the front end of the track frame, and the pair of front and rear swing arms One end of the connecting pin that rotatably connects the free end of the front swing arm to the upper end of the connection support and the free end of the rear swing arm of the pair of front and rear swing arms A swing link that is freely connected and has the other end rotatably connected to the rear end of the track frame;
The connecting support is configured such that the connecting pin has a rotating shaft center of a second grounded wheel adjacent to the first grounded wheel located on the most front side of the grounded wheel among the plurality of grounded wheels in a side view of the body. When the track frame is raised to the upper limit with respect to the aircraft frame so as to be positioned on a vertical line passing through, the pin axis of the connecting pin and the upper end surface of the track frame in the vertical direction of the aircraft The distance is configured to be equal to or greater than the distance between the pin axis of the connecting pin and the swing axis of the front swing arm in the vertical direction of the machine body.

  According to the configuration of the first aspect of the present invention, the connecting support that protrudes upward from the front end of the track frame and the free end of the front swing arm is rotatably connected to the upper end of the connecting support. A pin and a swing link having one end rotatably connected to the free end of the rear swing arm and the other end rotatably connected to the rear end of the track frame. As seen from the side, the connecting pin is positioned on a vertical line passing through the rotation axis of the second grounded wheel adjacent to the first grounded wheel located closest to the front of the body among the plurality of grounded wheels. When the track frame is raised to the upper limit, the distance between the pin shaft core of the connecting pin and the upper end surface of the track frame in the vertical direction of the machine body is such that the pin shaft core of the connecting pin and the front swing arm Of the vertical axis of the machine Since it is configured to be larger than the width, the connecting pin and the connecting support for the front end of the track frame are positioned while the free end of the swing arm on the front side is positioned relatively far upward from the track frame. When a large ground reaction force is applied to the second grounding wheel located at the front end of the track frame, the front swing arm can be connected to the second grounding wheel of the track frame. Can be supported via a connecting pin and a connecting support at or near the site where the track frame is connected, and when the track frame is lowered to the lower limit, the amount of lowering of the track frame from the body frame is greatly increased. Even when set, the swing position of the swing arm when the track frame is lowered to the lower limit swings at a relatively large angle from the vertical line passing through the swing axis of the swing arm to the ascending side. Becomes the position can be reduced as much as possible before and after the movement amount with respect to the machine frame of the track frame with the track frame is elevation operating by the swinging arm.

  Therefore, even when a large grounding reaction force is applied to the second grounding wheel, such as when the vehicle is stopped or over the heel, the second grounding wheel of the track frame connects the support by the swing arm on the front side of the track frame. It is possible to stably support the airframe by the traveling device, and to move the grounding part of the crawler belt back and forth relative to the airframe frame regardless of the change in the posture of the track frame relative to the airframe. The body can be stably supported by the traveling device with a small size. In addition, when the truck frame is lowered to the lower limit, the amount of lowering of the truck frame relative to the fuselage frame is increased so that the aircraft is positioned at a high level with respect to the mud layer even when the mud layer is deep. The vehicle can be advantageously run in a state where it is difficult to receive running resistance due to the mud layer.

  In the second aspect of the present invention, the airframe is provided with a stopper that sets the upper limit of the track frame in contact with the end of the connecting pin.

  According to the configuration of the second aspect of the invention, when the track frame is raised to the upper limit, the track frame is connected to the connection support and the connection even if a large ground reaction force is applied to the front end portion of the track frame due to stopping or overpass. It is supported by the stopper via the pin, and it is possible to effectively prevent a large load from being applied to the front swing arm.

  Therefore, even when the track frame is raised to the upper limit and the swing arm on the front side is in the raised posture and is in a disadvantageous state for receiving a heavy load from the track frame, It is possible to travel while protecting the swing arm from a heavy load.

  In the third aspect of the invention, the stopper is connected to a structure connected to the body frame so that a support portion for supporting the drive sprocket and the front swing arm is formed on the body frame.

  According to the configuration of the third aspect of the invention, the stopper can be firmly supported by using the structure configured to have a high strength so as to support the drive sprocket and the front swing arm as the support means.

  Therefore, the structure can be obtained with a simple structure using the support means, while the stopper can be strongly supported and the track frame can be firmly supported by the stopper via the connecting pin. it can.

It is a side view showing the whole work vehicle. It is a side view which shows a crawler traveling apparatus. (A) is a side view showing the crawler traveling device in a state where the fuselage frame is lowered to the lowering limit, and (b) is a side view showing the crawler traveling device in a state where the fuselage frame is raised to the rising limit. is there. It is a top view which shows a crawler traveling apparatus. It is a longitudinal cross-sectional view which shows a front part rocking | fluctuation mechanism. It is a longitudinal cross-sectional view which shows a rear part rocking | fluctuation mechanism. It is a side view which shows a crawler tension device. It is a top view which shows a crawler tension apparatus. It is a longitudinal cross-sectional view which shows a crawler tension device. It is a perspective view which shows the decomposition | disassembly state of a crawler tension device. The crawler tension ring support member is shown, (a) is a plan view, (b) is a front view, (c) is a left side view, and (d) is a right side view. It is sectional drawing which shows the fitting part of a guide rail part and an insertion part. It is a perspective view which shows the attachment structure of a drive sprocket, a rocking | swiveling arm, and a stopper. It is a top view which shows an operation part. It is a perspective view which shows the grip part of a control lever. It is a longitudinal cross-sectional view which shows the rear part rocking | fluctuation mechanism provided with another embodiment.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a side view showing an entire work vehicle according to an embodiment of the present invention. As shown in this figure, a work vehicle according to an embodiment of the present invention includes a traveling machine body 2 including a pair of left and right crawler traveling devices 1 and a driving unit 3 equipped with a driving seat 3a. The cutting part 4 with which the feeder 4a was connected to the front part, the threshing part 5 provided in the rear part of the traveling machine body 2, and the glen tank 5a are provided.

This work vehicle harvests grains such as rice and wheat.
That is, the mowing unit 4 is configured so that the feeder 4a is swung up and down with respect to the traveling machine body 2 by the hydraulic cylinder 4b, so that the lowering work state is lowered near the ground, and the non-working state is raised higher from the ground. Go up and down. When the cutting unit 4 is in the descending work state and the traveling machine body 2 is traveled, the cutting unit 4 cuts the planted cereal culm and feeds the whole of the cereal culm from the root to the tip of the cereal by the feeder 4a. Then, the threshing unit 5 threshs the harvested cereal meal and sends the threshed grains to the glen tank 5a.

  FIG. 2 is a side view showing the crawler traveling device 1. FIG. 4 is a plan view showing the crawler traveling device 1. As shown in these drawings, the crawler traveling device 1 includes a driving sprocket 6 positioned on the front side of the body of the crawler traveling device 1, a crawler tensioning wheel 7 positioned on the rear side of the body of the crawler traveling device 1, a driving sprocket 6 and the crawler. A plurality of grounding rollers 8 a, 8 b, 8 c, 8 d disposed between the tension wheels 7, a track frame 12 disposed between the drive sprocket 6 and the crawler tension wheels 7, and the grounding between the drive sprocket 6 and the crawler tension wheels 7. A rubber crawler belt 9 wound around the rollers 8a, 8b, 8c, 8d, an upper roller 10 for supporting the crawler belt 9 from the inner peripheral side, and a guide 9a for preventing the crawler belt 9 from coming off. It is prepared.

  The track frame 12 is supported on the body frame 11 of the traveling device 2 via a pair of front and rear swing arms 18a and 18b. The drive sprocket 6 and the upper wheel 10 are supported on the body frame 11 side. The crawler tension ring 7 is supported on the rear portion of the track frame 12. The grounding wheels 8a, 8b, 8c, 8d are rotatably supported on the track frame 12 in the longitudinal direction of the machine body.

  As shown in FIGS. 2, 4, and 5, the crawler belt 9 has a core metal 13 having a pair of left and right core metal protrusions 13 a protruding toward the inner peripheral surface of the crawler belt 9 at a constant pitch in the front-rear direction. Buried. Of the grounding wheels 8a, 8b, 8c, and 8d, the grounding wheels 8a, 8b, and 8c are configured to include a pair of left and right wheel bodies to form outer wheels, and the left and right metal core protrusions 13a. It is mounted so as to straddle the outside from the left and right. Of the grounding rollers 8a, 8b, 8c, and 8d, the grounding wheel 8d is configured to have a single ring body portion and serves as an inner wheel, and is engaged between the left and right metal core protrusions 13a. It is installed to enter. The crawler tension ring 7 and the upper roller 10 are mounted so as to be engaged between the left and right core metal protrusions 13a. The drive sprocket 6 is engaged with a drive hole formed in the crawler belt 9 between the core bars 13.

  The body frame 11 is configured in a deck shape that extends over substantially the entire width of the lower part of the traveling body 2, and supports the deck frame 14 on which the above-described threshing portion 5 and the like are mounted, the drive sprocket 6 and the upper wheel 10. And a fixed frame 15 that is long in the longitudinal direction of the machine body.

  The fixed frame 15 is fixed to the lower surface side of the deck frame 14. An attitude changing mechanism 16 that can change the attitude of the track frame 12 with respect to the body frame 11 in the vertical direction is provided across the fixed frame 15 and the track frame 12.

The posture change mechanism 16 is configured by providing a front swing mechanism 16 a on the front side of the machine body and a rear swing mechanism 16 b on the rear side of the machine body across the fixed frame 15 and the track frame 12.
As shown in FIGS. 5 and 6, the front swing mechanism 16a and the rear swing mechanism 16b are respectively provided with swing support shafts 17a supported on the fixed frame 15 in a lateral direction toward the outer side of the machine body. 17b, swinging arms 18a and 18b supported on the swinging support shafts 17a and 17b so as to swing up and down, and operation arms 19a and 19b supported on the swinging support shafts 17a and 17b so as to swing freely. And. Each of the swing support shafts 17a and 17b is arranged at a position higher than the track frame 12 in a state where the outer sides of the swing support shafts 17a and 17b enter the inner peripheral side of the crawler belt 9.

  Each of the swing support shafts 17a and 17b penetrates the fixed frame 15 and is supported by the fixed frame 15 so as to be rotatable around the axis Xa and Xb. The swinging arms 18a and 18b are integrally fixed to the projecting end side, and the operation arms 19a and 19b are integrally fixed to the projecting end side of the swinging support shafts 17a and 17b toward the body side. Each of the swing arms 18a and 18b is configured such that the swing support shafts 17a and 17b are fitted into bosses 20a and 20b integrally provided on one end side of the swing arms 18a and 18b. Rotating shaft cores Xa and Xb of the swing support shafts 17a and 17b are used as swing shaft cores Xa and Xb, and swing about the swing shaft cores Xa and Xb with respect to the body frame 11. Move up and down.

  A free end portion of the swing arm 18a in the front swing mechanism 16a is rotatably connected to an upper end portion of a connection support body 21 projecting upward from the front end portion of the track frame 12 by a connection pin 21a. It is. The connection support 21 is fixed to the track frame 12.

  As shown in FIGS. 2, 3, and 5, the connecting support body 21 includes a pair of inner and outer sheet metal support bodies 21 d and 21 d that are distributed on the outer side and the inner side of the track frame 12. , A laterally facing boss member 21e connected to the upper ends of the pair of inner and outer support bodies 21d and 21d, and a pair of front and rear sheet metal reinforcing members 21f and 21f arranged dispersed on the front and rear sides of the boss member 21e. And has a box shape.

  The pair of inner and outer support bodies 21d and 21d extend upward from the side of the upper end of the track frame 12 on the outer side or the inner side of the body. The pair of front and rear reinforcing members 21f and 21f are connected to the upper surface of the track frame 12 and the inner surface of the pair of front and rear support bodies 21d by welding in a state of being disposed between the pair of front and rear support bodies 21d and 21d. . The boss member 21 e has a boss portion into which the connection pin 21 a is fitted at the upper end portion of the connection support 21.

  The free end portion of the swing arm 18 b in the rear swing mechanism 16 b is connected to the track frame 12 via the swing link 22. One end side of the swing link 22 is rotatably connected to the swing arm 18b by a connecting pin 22b, and the other end side of the swing link 22 is rotatably connected to the track frame 12 by a connecting pin 22a.

  The operation arms 19a and 19b of the front swing mechanism 16a and the rear swing mechanism 16b are connected by a connecting rod 23 to form a four-link. A hydraulic cylinder 24 is connected to the operation arm 19b of the rear swing mechanism 16b and the deck frame 14.

  FIG. 3A is a side view showing the crawler traveling device 1 in a state in which the body frame 11 is lowered to the lower limit. As shown in FIG. 2 and FIG. 2, when the operation arms 19a and 19b are swung to the front side of the machine body by the contraction operation of the hydraulic cylinder 24, the swing arms 18a and 18b are swung upward. The track frame 12 is lifted with respect to the body frame 11 so as to be close to the body frame 11 by the pair of front and rear swing arms 18a and 18b, and the ground height of the body frame 11 is lowered. As the track frame 12 moves up, an end portion 21b protruding from the swing arm 18a of the connecting pin 21a attached to the swing arm 18a of the front swing mechanism 16a toward the body side (see FIG. 5). ) Abuts against the horizontal surface of the lower end of the rectangular stopper 50 that is long in the vertical direction in the side view provided on the body frame 11 and is disposed on the track frame 12 so as to be disposed near the front side of the swing link 22. The upper end of the member 27 comes into contact with a boss portion 20b (see FIG. 6) in which the swing support shaft 17b of the rear swing mechanism 16b is fitted, and the track frame 12 is set by the stopper 50 and the contact member 27. It will be in the state which rose to the ascent limit, and the ground height of the body frame 11 will become the lowest.

At the upper end of the contact member 27, a horizontal surface 27a for stably supporting the boss 20b is formed. A curved surface that is recessed downward in a U shape in a side view along the outer peripheral surface of the boss 20b or a contact surface that is recessed downward in a V shape in a side view is formed at the upper end of the contact member 27. May be.

  FIG. 3B is a side view showing the crawler traveling device 1 in a state where the body frame 11 is raised to the ascent limit. As shown in this figure, when each operation arm 19a, 19b is swung to the rear side of the machine body by the extension operation of the hydraulic cylinder 24, each swing arm 18a, 18b is swung downward, and the track frame 12 Is lowered with respect to the body frame 11 so as to be separated from the body frame 11 by the pair of front and rear swing arms 18a and 18b, and the ground height of the body frame 11 is increased.

  Accordingly, by independently operating the hydraulic cylinders 24 provided in each of the posture changing mechanisms 16 in the left and right crawler traveling devices 1, the ground height on the left and right of the airframe frame 11 is changed and adjusted, and the airframe frame 11 even on an inclined ground. Can be held substantially horizontally.

  The connecting support 21 is configured as shown in FIGS. 3 (a) and 3 (b). That is, the connecting pin 21a that connects the swing arm 18a of the front swing mechanism 16a to the connection support 21 is the frontmost side of the body among the plurality of grounded wheels 8a, 8b, 8c, and 8d in a side view of the body. The pin shaft core 21c of the connecting pin 21a and the track frame so as to be positioned on the vertical line Z passing through the rotation shaft core P of the second grounding wheel 8b adjacent to the first grounding wheel 8a positioned at The distance D1 between the upper end surface 12c and the upper end surface 12c in the vertical direction of the machine body is such that the track axis 12 and the pivot axis 21c of the connecting pin 21a in the state where the track frame 12 is raised to the upper limit with respect to the machine frame 11 The connection support 21 is configured to be larger than the distance D2 between the swing axis 18a of the 18a.

  Therefore, the free end portion of the swing arm 18a in the front swing mechanism 16b is located at a position relatively far upward from the track frame 12, while the connection pin 21a and the connection support 21 are connected to the front end portion of the track frame 12. The swing arm 18a is in a state of supporting and acting via the connection pin 21a and the connection support body 21 at or near the portion where the second grounding wheel 8b of the track frame 12 is connected. While the amount of lowering of the track frame 12 from the body frame 11 when the operation of lowering the frame 12 to the lowering limit is set relatively large, the swing arm 18a of the swinging arm 18a when the track frame 12 is lowered to the lowering limit is set. The swing position is a position that swings from the vertical line passing through the swing axis Xa toward the rear side and the ascending side of the machine body.

  As shown in FIG. 4, the drive sprocket 6 includes a drive shaft (not shown) housed in a transmission cylinder 52 that extends outward from the lateral side of the mission case 51 connected to the front end of the aircraft frame 11. )) And is connected to the end portion of the device so as to be integrally rotatable.

  FIG. 13 is a perspective view showing a mounting structure of the drive sprocket 6, the swing arm 18 a and the stopper 50. As shown in FIG. 4 and FIG. 4, the fixed frame 15 in the body frame 11 has a support portion provided at the front end portion of the fixed frame 15 by connecting a structure 53 to the lateral side portion on the front end side of the fixed frame 15. 15a. The support portion 15 a of the fixed frame 15 supports the drive sprocket 6 rotatably by connecting the transmission cylinder 52 to the flange 15 b located at the front end portion of the structure 53. The support portion 15a of the fixed frame 15 has a swing support shaft 17a penetrating through an intermediate portion of the fixed frame 15 and the structural body 53 in the longitudinal direction of the machine body, so that the swing arm 18a of the front swing mechanism 16a. Is supported in a swingable manner. The support portion 15 a of the fixed frame 15 supports the stopper 50 by connecting the stopper 50 to the rear end portion of the structure 53.

  The stopper 50 is connected to the outer side surface of the rear end portion of the support portion 15 in a state where the stopper 50 is disposed in the vicinity of the horizontal frame 15c that is connected to the support portion 15 and faces the machine body.

  The structure 53 includes a sheet metal member 53a connected to the outer surface of the fixed frame 15, a bent sheet metal 53b having a U-shaped secondary cross section connected to the outer surface of the sheet metal member 53, and a front portion of the bent sheet metal 53b. The secondary cross-sectional shape connected to the outer surface is a U-shaped bent sheet metal 53c, and the flange 15b is connected to the front end portions of the bent sheet metals 53b and 53c.

  As shown in FIGS. 4 and 13, the stopper 50 that contacts the connecting pin 21 a that connects the swing arm 18 a of the front swing mechanism 16 a to the connection support portion 21 is connected to the rear end portion of the structure 53. As a result, the rear end portion of the support portion 15 a provided on the fixed frame 15 is connected.

  As shown in FIG. 6, the swinging support shaft 17b of the rear swinging mechanism 16b is provided with an extending portion 25 extending laterally outward from the swinging arm 18b. The wheel 10 is rotatably supported.

  Therefore, the upper roller 10 that supports the crawler belt 9 can be supported with a simple structure so as to enter the inner peripheral side of the claw label 9 by using the posture changing mechanism 16.

  In other words, the posture changing mechanism 16 includes a swing support shaft 17b that is supported on the body frame 11 in a lateral direction toward the laterally outer side of the body, and is driven by swinging of the swing arm 18b around the swing support shaft. Since the posture of the track frame 12 with respect to the body frame 11 can be changed in the vertical direction, the swing support shaft 17b has a high strength capable of supporting the weight of the body and enters the inner peripheral side of the crawler belt 9. It is out. The swing support shaft 17b is extended laterally outward from the swing arm 18b, and the upper roller 10 supporting the crawler belt 9 is supported by the extended portion 25. The roller 10 can be supported with sufficient strength by the short extending portion 25 of the swing support shaft 17b, and the upper roller 10 can be supported with a simple structure.

  As shown in FIG. 6, the swing support shaft 17b of the rear swing mechanism 16b is a pin in a state where a support shaft member 25 different from the swing support shaft 17b is fitted in the tip hole portion of the swing support shaft 17b. Connected to each other and extended to the outer side of the aircraft. The upper roller 10 is supported on a support shaft member (extended portion) 25 via a bearing 26 so as to be freely rotatable.

The support structure of the crawler tension ring 7 will be described.
As shown in FIGS. 1 to 4, the crawler tensioning wheel 7 is attached to a crawler tensioning device 28 provided on the rear end side of the truck frame 12 in the longitudinal direction of the machine body.

  The track frame 12 includes a lower track frame 12a that supports the grounded wheels 8a, 8b, 8c, and 8d, and an upper track frame 12b that is connected to the upper side of the lower track frame 12a and to which the connection support 21 is attached. Have. The upper track frame 12b is made of a commercially available steel square pipe having a square cross section.

  As shown in FIGS. 7 to 9, the crawler tensioning device 28 includes a rectangular tube-shaped guide rail portion 29 constituted by a rear end portion in the longitudinal direction of the machine body of the upper track frame 12 b, the crawler tensioning wheel 7, A crawler tension ring support member 30 supported by the guide rail portion 29 and an adjustment screw shaft 31 for adjusting the tension applied to the crawler belt 9 by the crawler tension ring 7 are provided.

  As shown in FIGS. 10 and 11, the crawler tension ring support member 30 has a quadrangular cross-section that is slidably fitted in the support shaft 32 that rotatably supports the crawler tension ring 7 and the guide rail portion 29. And a tension frame 34 having a rectangular tube-shaped insertion portion 33.

The tension frame 34 has a screw shaft insertion portion 36 in which a pair of screw shaft insertion holes 35 into which the adjustment screw shaft 31 can be inserted is formed on one end side, and the support shaft 32 is attached to the screw shaft insertion portion 36. It is integrally cast.

  The adjustment screw shaft 31 adjusts the insertion depth of the insertion portion 33 of the tension frame 34 with respect to the guide rail portion 29, thereby changing the support position of the crawler tension ring 7 in the longitudinal direction of the machine body and applying tension to the crawler belt 9. Is to adjust.

  One end of the adjustment screw shaft 31 is supported in a non-rotating state by a screw support 37 provided on the upper track frame 12b, and the other end is a female screw mounted in one screw shaft insertion hole 35 of the screw shaft insertion portion 36. Screwed into the member 38. The female screw member 38 is screwed to the screw shaft insertion portion 36.

  The screw support 37 includes a screw shaft hole 40 formed in a boss portion of the screw support 37 through which a hexagonal shaft-shaped operation unit 39 provided at the front end of the adjustment screw shaft 31 is rotatably operated. A stopper surface 42 that comes into contact with the flange 41 that is provided integrally with the adjustment screw shaft 31 is provided to receive and support the reaction force from the adjustment screw shaft 31 that accompanies tension on the crawler belt 9.

  The operation portion 39 inserted through the screw shaft hole 40 is inserted through a rotation prevention hole 44 formed in a rectangular plate-shaped rotation prevention body 43. The anti-rotation hole 44 is formed in a hexagonal shape with which the operation portion 39 is engaged, so that the side portion of the anti-rotation body 43 abuts against the outer surface of the guide rail portion 29, thereby rotating the adjustment screw shaft 31. Stopped. Further, a retaining pin 45 for retaining the rotation preventing body 43 is removably inserted into the operation portion 39.

  Therefore, the female screw member 38 moves with respect to the adjusting screw shaft 31 by removing the rotation stopper 43 from the operation portion 39 and rotating the operation portion 39, so that the support position of the crawler tension ring 7 is set to the front and rear of the machine body. The tension applied to the crawler belt 9 can be adjusted by changing the direction.

  The entire crawler tension ring support member 30 is integrally formed of a casting such as ductile cast iron, and the square pipe-shaped (hollow) insertion portion 33 is machined into an outer surface shape along the inner surface of the guide rail portion 29. The support shaft 32 is machined into a circular cross section so as to support the crawler tension ring 7. A lid that closes the inside of the insertion portion 33 on the side of the support shaft 32 is integrally formed of a casting, and the end of the insertion portion 33 opposite to the support shaft 32 side is open. .

Accordingly, as shown in FIG. 12, when the torsional moment M around the insertion portion center 46 is generated in the insertion portion 33 using the guide rail portion 29 as a reaction force receiver, the moment lever length L from the insertion portion center 46 is increased. Thus, the outer radius of curvature r1 at the corner portion 48 is set to a desired value so that the reaction force F acting on the insertion portion 33 can be reduced, that is, the width B of the outer plane portion 47 of the insertion portion 33 is increased. A tension frame 34 having a rectangular tube-shaped insertion portion 33 formed in a radius of curvature can be provided.
In FIG. 12, the difference between the inner peripheral surface dimension of the guide rail portion 29 and the outer peripheral surface dimension of the insertion portion 33 is exaggerated from the actual one.

  As shown in FIGS. 10 and 11, the tension frame 34 has the insertion portion 33 so that the center line Y33 of the insertion portion 33 intersects the center line Y32 of the support shaft 32, and the center line of the insertion portion 33 A symmetric shape is formed across the virtual plane S including Y33 and the center line Y32 of the support shaft 32, and a pair of screw shaft insertion holes 35 are formed in symmetrical positions across the imaginary plane S.

  Therefore, the tension frame 34 is assembled corresponding to one crawler belt 9 with one side sandwiching the virtual plane S facing upward, and corresponding to the other crawler belt 9 with the other side sandwiching the virtual plane S facing upward. Thus, the common crawler tension ring support member 30 can be assembled symmetrically corresponding to each of the left and right crawler belts 9.

  That is, in FIGS. 7 to 10, the crawler tension ring support member 30 attached to the crawler tension device 28 on the left side of the machine body is shown, but the adjustment screw shaft 31 is inserted into the other screw shaft insertion hole 35 of the screw shaft insertion portion 36. As a result, it can be used as a crawler tension ring support member 30 attached to the crawler tension device 28 on the right side of the machine body.

  FIG. 14 is a plan view showing the operation unit 3. As shown in this figure, the driving unit 3 includes a control tower 53 provided on the driver's seat 3a, a fixed handle 54 projecting rearward from the upper part of the control tower 53, and an operation provided on the upper part of the control tower 53. A panel 55 is provided. The operation panel 55 is provided with a control lever 56, an instrument panel 57, a headlight switch 58, a posture operation switch 59, and a rolling control changeover switch 60.

  The control lever 56 is configured by a cross lever that can be swung in the front-rear direction and the left-right direction of the traveling machine body 2, and is operated by swinging in the front-rear direction of the traveling machine body 2, thereby operating the hydraulic cylinder 4b. By operating the mowing unit 4 up and down and swinging in the left-right direction of the traveling machine body 2, the steering mechanism for increasing / decreasing or changing the driving speed and driving direction of the left / right crawler traveling device 1 is operated. Then, the steering operation of the traveling machine body 2 is performed. The instrument panel 57 includes an engine tachometer. The posture operation switch 59 operates the hydraulic cylinder 24 of the left crawler traveling device 1 and the right crawler traveling device 1 separately to operate the ground posture of the traveling machine body 2 to a state of rising to the right or rising to the left. The rolling control changeover switch 60 operates the hydraulic cylinder 24 of the left crawler traveling device 1 and the right crawler traveling device 1 based on the detection result by the inclination sensor to automatically move the traveling machine body 2 to the horizontal posture in the left-right direction. The rolling control to be maintained is switched between the on state and the off state.

  FIG. 15 is a perspective view showing the grip portion 56 a of the control lever 56. As shown in this figure, the grip portion 56a of the control lever 56 includes a pair of left and right steering switches 61a and 61b provided on the upper surface of the grip portion 56a, and a lowering switch disposed on the front side of the steering switches 61a and 61b. 62 and a raising switch 63 disposed on the rear side of the steering switches 61a and 61b.

  When the left steering switch 61a is pushed, the steering clutch (not shown) acting on the left crawler travel device 1 is switched to a disconnected state. When the right steering switch 61b is pushed, the steering clutch (not shown) acting on the right crawler traveling device 1 is switched to a disconnected state.

  When the raising switch 63 is pushed, it raises the pulling reel 4c (see FIG. 1) provided in the cutting unit 4. The lowering switch 62 is pushed to raise and lower the reel 4c. The raising switch 63 and the lowering switch 62 are continuously raised and lowered to raise or lower the reel 4c while being maintained in the pressed state. The raising and lowering operations of the raising reel 4c by the raising switch 63 and the lowering switch 62 are disabled while the raising and lowering operation of the cutting unit 4 by the swinging operation of the control lever 56 is performed. That is, the raising / lowering operation of the cutting unit 4 by the swinging operation of the control lever 56 is performed in preference to the raising / lowering operation of the raising reel 4c by the raising switch 63 and the lowering switch 62.

[Another embodiment]
FIG. 16 is a longitudinal sectional view showing a rear rocking mechanism 16b provided with another embodiment. As shown in this figure, in the rear swing mechanism 16b provided with another embodiment, a boss portion 18c is formed integrally with the swing arm 18b, and the upper tumbling member 50c is supported via a support shaft member 50. The wheel 10 is rotatably supported.

[Another Example]
(1) In the above-described embodiment, the size of the distance D1 between the pin shaft core 21c of the connecting pin 21a and the upper end surface 12c of the track frame 12 in the vertical direction of the airframe increases with respect to the track frame 12 with respect to the airframe frame 11. Although the example in which the connection support 21 is configured to be larger than the distance D2 between the pin axis 21c of the connection pin 21a and the swing axis Xa of the swing arm 18a in the state of being raised to the limit is shown, Instead, the size of the distance D1 between the pin axis 21c of the connecting pin 21a and the upper end surface 12c of the track frame 12 in the vertical direction of the machine body is increased to the upper limit of the track frame 12 with respect to the machine frame 11. The connecting support 21 is configured so that the distance D2 between the pin axis 21c of the connecting pin 21a and the swing axis Xa of the swing arm 18a is the same as the distance D2. It may also be carried out. Also in this case, the object of the present invention can be achieved.

  (2) In the above-described embodiment, the pin shaft core 21c of the connecting pin 21a is deviated backward with respect to the vertical line Z, but instead, the pin shaft core 21c of the connecting pin 21a is the vertical line. An arrangement that matches Z, or an arrangement in which the pin axis 21c of the connecting pin 21a is slightly deviated forward from the vertical line Z may be adopted.

  INDUSTRIAL APPLICABILITY The present invention can be used for various work vehicles such as a tractor that is connected to a tillage device and constitutes a tiller other than a work vehicle that harvests grains.

DESCRIPTION OF SYMBOLS 1 Traveling device 6 Drive sprocket 7 Crawler tension wheel 8a, 8b, 8c, 8d Grounding wheel 9 Crawler belt 11 Machine body frame 12 Track frame 12c Track frame upper end surface 15a Machine frame support part 18a, 18b Swing arm 21 Connection support Body 21a Connecting pin 21b Connecting pin end 21c Pin shaft core 22 Swing link 50 Stopper 53 Structure P Rotating shaft center Z of the second grounding wheel Vertical line D1 The upper and lower sides of the body between the pin shaft core and the upper surface of the track frame Interval in the direction D2 Interval between the pin axis and the oscillating axis of the oscillating arm in the vertical direction Xa Oscillating axis of the oscillating arm

Claims (3)

A drive sprocket that is supported by the machine frame so as to be driven to rotate, a plurality of ground wheels that are supported by the track frame so as to be rotatable in the longitudinal direction of the machine, a crawler tension ring that is supported at the rear of the track frame, and the drive sprocket And a work vehicle having a traveling device provided with a crawler belt wound around the plurality of grounding wheels and the crawler tension wheel,
Of the pair of front and rear swing arms connected to the body frame so as to freely swing up and down, a connecting support projecting upward from the front end of the track frame, and the pair of front and rear swing arms One end of the connecting pin that rotatably connects the free end of the front swing arm to the upper end of the connection support and the free end of the rear swing arm of the pair of front and rear swing arms A swing link that is freely connected and has the other end rotatably connected to the rear end of the track frame;
The connecting support is configured such that the connecting pin has a rotating shaft center of a second grounded wheel adjacent to the first grounded wheel located on the most front side of the grounded wheel among the plurality of grounded wheels in a side view of the body. When the track frame is raised to the upper limit with respect to the aircraft frame so as to be positioned on a vertical line passing through, the pin axis of the connecting pin and the upper end surface of the track frame in the vertical direction of the aircraft A work vehicle configured such that the distance is equal to or greater than the distance between the pin axis of the connecting pin and the swing axis of the front swing arm in the vertical direction of the machine body.   The work vehicle according to claim 1, wherein a stopper for setting an upper limit of the track frame in contact with an end portion of the connection pin is provided on the body frame.   3. The work vehicle according to claim 2, wherein the stopper is connected to a structure connected to the airframe so that a support portion for supporting the drive sprocket and the front swing arm is formed on the airframe.

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