JP2018144663A - Service car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a distance between right and left truck frames to be easily changed.SOLUTION: A service car includes right and left crawlers each having a truck frame 31 supported by a support shaft 14 on a vehicle body frame, and a frame position changing mechanism 55 configured to change an attachment position of the truck frame 31 to the support shaft 14 in the right to left direction. The frame position changing mechanism 55 includes a first connection member 56 for the support shaft, a second connection member 57 for the truck frame, and plural connection devices 58 connecting the connection members 56, 57. A connection position of the second connection member 57 to the first connection member 56 is selected by a sliding movement of the second connection member 57 to the first connection member 56 in the right to left direction along a mounting surface 57a of the second connection member 57. In addition, the first connection member 56 and the second connection member 57 include connection portions 56b, 57b via which the second connection member 57 can be connected to the first connection member 56 in the selected connection position by the connection devices 58.SELECTED DRAWING: Figure 5

Description

  The present invention includes left and right crawlers disposed on the left and right of the body frame, left and right drive shafts extending left and right from the transmission unit, left and right support shafts extending left and right from the body frame, The present invention relates to a work vehicle including a tread changing unit that changes a tread of the crawler.

  As a work vehicle as described above, there is a vehicle configured in a semi-crawler specification by including left and right crawlers instead of left and right rear wheels. The left and right crawlers equipped on semi-crawler specification work vehicles swing left and right drive sprockets that rotate together with the left and right drive shafts, and the vehicle body frame (transmission case) via left and right support shafts (swing shafts). Left and right track frames supported posteriorly, a front idler supported at the front ends of the left and right track frames 31, a rear idler supported at the rear ends of the left and right track frames, and left and right tracks A plurality of wheels supported by the middle part of the front and rear of the frame, and left and right crawler belts rotated by the left and right drive sprockets and guided by the front and rear idlers and wheels. There are some (see, for example, Patent Document 1).

The work vehicle described in Patent Document 1 includes the left and right crawlers as described above, so that when the cultivator in the field has ups and downs, the idler wheel and each rolling wheel before and after rotating and guiding the grounding side of the crawler belt. However, it swings up and down together with the track frame around the support shaft according to the unevenness of the tiller. Thereby, the ground contact side of the crawler belt can be made to follow the ups and downs of the tiller, and regardless of the ups and downs of the tiller, the contact area of the left and right crawlers is widened and the grip force of the left and right crawlers is increased. As a result, the running performance by the left and right crawlers is increased.
In addition, since a dedicated support shaft for swinging the left and right track frames is provided, for example, the burden on the left and right drive shafts is reduced as compared with the case where the left and right drive shafts are also used as the support shafts. be able to. Thereby, the durability of the left and right drive shafts can be improved.

  Some semi-crawler specification work vehicles are used in fields where wide left and right straws for cultivating crops such as onions are formed. Even if it is for cultivating the same crop, the left and right widths of the pods formed in the field may differ depending on the cultivated area. Therefore, some semi-crawler specification work vehicles are configured such that the left and right front wheel treads and the left and right crawler treads can be changed.

  Patent Document 1 described above shows a configuration for enabling the tread change of the left and right crawlers.

  More specifically, in the work vehicle described in Patent Document 1, the left and right centers of the left and right drive sprockets are offset in the left and right direction with respect to the attachment portion of the drive sprocket attached to the left and right drive shafts. As a result, the left and right drive sprockets are mounted on the left and right drive shafts with their left and right centers positioned on the inner side of the vehicle body relative to the mounting portion, thereby reducing the spacing between the left and right drive sprockets. Further, the left and right drive sprockets are attached to the left and right drive shafts in a state where their left and right centers are located on the outer side of the vehicle body with respect to the attachment portion, thereby widening the distance between the left and right drive sprockets.

  In the work vehicle described in Patent Document 1, the left and right cylindrical portions that support the left and right support shafts so that the left and right support shafts can move in the axial direction and rotate around the shaft center, and the left and right support shafts move in the left and right directions. Select between the left and right restricting members attached to the left and right ends of each support shaft and between the left and right inner restricting members and the cylinder part, or between the left and right outer restricting members and the cylinder part. Left and right spacers are provided. As a result, when the left and right spacers are interposed between the right and left inner regulating members and the cylindrical portion, the distance between the left and right track frames attached to the left and right support shafts is reduced and supported by the left and right track frames. The intervals between the left and right front idle wheels, the intervals between the left and right rear idle wheels, and the intervals between the left and right wheels are reduced. Further, when the left and right spacers are interposed between the left and right regulating members and the cylindrical portion, the distance between the left and right track frames attached to the left and right support shafts is widened and supported by the left and right track frames. Further, the distance between the left and right front idlers, the distance between the left and right rear idlers, and the distance between the left and right wheels are increased.

  That is, in the work vehicle described in Patent Document 1, by changing the attachment state of the left and right drive sprockets to the left and right drive shafts and changing the attachment positions of the left and right spacers, It can be changed to a narrow tread corresponding to a narrow ridge and a wide tread corresponding to a wide ridge.

JP 2003-276657 A

  In the work vehicle described in Patent Document 1, when changing the distance between the left and right track frames, it is necessary to remove the left and right support members from the left and right support shafts and to extract the left and right support shafts from the left and right cylindrical portions. is there. When removing the right and left inner regulating members from the left and right support shafts, the operator needs to insert his arms and the like from the lateral outer side of the vehicle body toward the interior of the vehicle body. Further, in order to extract the left and right support shafts from the left and right cylindrical portions, it is necessary to move the track frame or the like in the left-right direction with an operation amount larger than the change amount of the track frame interval. As a result, changing the interval between the left and right track frames is troublesome and cumbersome.

  In other words, it is desired to easily change the interval between the left and right track frames.

As means for solving the above problems,
A work vehicle according to the present invention includes left and right crawlers disposed on the left and right of a body frame, left and right drive shafts extending left and right from the transmission unit, and left and right support shafts extending left and right from the body frame. And a tread changing unit that changes the tread of the left and right crawlers,
The crawler includes a drive sprocket that rotates integrally with the drive shaft, a track frame that is swingably supported by the body frame via the support shaft, and a front idler that is supported by a front end portion of the track frame, A rear idler supported by the rear end of the track frame, a plurality of wheels supported by the front and rear intermediate parts of the track frame, and rotated by the rotation of the drive sprocket; A crawler belt that is pivotally guided by the wheel,
The tread changing unit includes a frame position changing mechanism that changes a mounting position of the track frame with respect to the support shaft in a left-right direction,
The frame position changing mechanism includes a first connecting member fixed to an end of the support shaft on the track frame side, a second connecting member extending from the track frame so as to be connectable to the first connecting member, A plurality of couplers for coupling the first coupling member and the second coupling member;
A mounting surface is formed on one of the first connecting member and the second connecting member, and the mounting surface is mounted on the other of the first connecting member and the second connecting member. A mounting surface is formed,
The first connecting member and the second connecting member may be configured such that the second connecting member with respect to the first connecting member is slid in the left-right direction of the second connecting member with respect to the first connecting member along the placement surface. And a connecting portion that enables the first connecting member and the second connecting member to be connected by the connecting tool at the selected connecting position.

  According to this means, when changing the interval between the left and right track frames, first, as a procedure, the connection between the first connecting member and the second connecting member by the plurality of connecting members is released. Next, the second connecting member is slid in the left-right direction along the placement surface together with the track frame or the like to change the connecting position of the second connecting member with respect to the first connecting member. Thereafter, the first connection member and the second connection member are connected by a plurality of connectors in a state where the mounting surface and the mounting surface are brought into surface contact at the changed connection position.

  That is, the operator can change the distance between the left and right track frames without changing the support shaft by changing the connecting position of the second connecting member with respect to the first connecting member.

  And since the 1st connection member is being fixed to the edge part by the side of the track frame in a spindle, ie, the horizontal outer end side of the vehicle body in a spindle, an operator is the 2nd connection member with respect to a 1st connection member. Can be connected and disconnected from the outside of the vehicle body without difficulty.

  As a result, the interval between the left and right track frames can be easily changed to an interval suitable for the left and right widths of the pods depending on the region to be cultivated or the type of crop.

As one of the means for making the present invention more suitable,
The connecting portion of the first connecting member is constituted by a plurality of first round holes formed at regular intervals in the left-right direction in the first connecting member,
The connecting portion of the second connecting member is configured by a plurality of second round holes formed at regular intervals in the left-right direction in the second connecting member,
The arrangement interval of the first round hole and the second round hole is set to a half length with respect to the change length of the tread,
The quantity of one of the first round hole and the second round hole is the same quantity as the quantity of the connector, and the quantity of the other of the first round hole and the second round hole is The quantity obtained by adding the quantity corresponding to the number of steps of the tread to the quantity of the coupling tool.

  According to this means, the number of connectors used for connecting the first connecting member and the second connecting member is the same regardless of the change in the connecting position of the second connecting member relative to the first connecting member. Thereby, the connection intensity | strength of a 1st connection member and a 2nd connection member can be made the same irrespective of the change of a connection position.

  Moreover, compared with the case where a long hole is employ | adopted as the connection part of a 1st connection member or a 2nd connection member, the hole formation area in a 1st connection member or a 2nd connection member decreases. Thereby, the fall of the intensity | strength in a 1st connection member or a 2nd connection member resulting from providing a connection part can be suppressed.

As one of the means for making the present invention more suitable,
One of the first connecting member and the second connecting member is provided with a restricting portion that restricts a positional shift of the second connecting member in the front-rear direction with respect to the first connecting member.

  According to this means, when changing the connection position of the 2nd connection member with respect to the 1st connection member, it becomes easy to slide the 2nd connection member to the left-right direction with respect to the 1st connection member. This makes it easier to change the interval between the left and right track frames.

As one of the means for making the present invention more suitable,
The mounting surface is formed on the first connecting member, and the mounting surface is formed on the second connecting member;
The track frame includes a support member that supports a base end side of the second connecting member from below.
Regardless of the change in the connection position of the second connection member with respect to the first connection member, the end portion on the track frame side of the placement surface is located within the support region of the support member on the placement surface. Yes.

  According to this means, regardless of the change of the connecting position of the second connecting member with respect to the first connecting member, the first connecting member is the end of the mounting surface on the track frame side, that is, the side of the vehicle body on the mounting surface. The outer end portion is received and supported from below by the support member of the track frame via the base end side of the second connecting member.

  As a result, regardless of the change in the connection position of the second connection member with respect to the first connection member, the first connection member on the vehicle body frame side can be suitably received and supported with good stability from below by the support member on the crawler side. .

It is a left view of the tractor comprised by the semi-crawler specification. It is a partially longitudinal left side view of the crawler. It is a partial longitudinal rear view of the principal part showing a state where the treads of the left and right crawlers are changed to the first tread. It is a partial longitudinal rear view of the principal part showing a state where the treads of the left and right crawlers are changed to the second tread. It is a disassembled perspective view of a frame position change mechanism. It is a vertical left side view of a frame position changing mechanism.

Hereinafter, as an example of an embodiment for carrying out the present invention, an embodiment in which the present invention is applied to a semi-crawler specification tractor which is an example of a work vehicle will be described with reference to the drawings.
The direction indicated by the arrow F shown in FIG. 1 is the front side of the tractor, and the direction indicated by the arrow U is the upper side of the tractor.

  As shown in FIG. 1, the tractor exemplified in the present embodiment is supported by a body frame 1 forming a framework, a driving unit 2 supported on the front side of the body frame 1, and a rear side of the body frame 1. The boarding type driving unit 3, the transmission unit 4 disposed below the driving unit 3, the left and right front wheels 5 disposed so as to be steerable and driveable to the left and right of the body frame 1, and the drive unit disposed on the left and right of the body frame 1 The left and right crawlers 6 and the protective frame 7 connected to the rear end of the vehicle body frame 1 are provided. That is, this tractor is configured in a semi-crawler specification including left and right crawlers 6 instead of left and right rear wheels.

  As shown in FIGS. 1 to 5, the vehicle body frame 1 includes a front frame 8 disposed at the front portion of the vehicle body, an intermediate frame 9 disposed at the front and rear intermediate portion of the vehicle body, and a rear frame 10 disposed at the rear portion of the vehicle body. And a support frame 11 connected to the bottom of the rear frame 10. The front frame 8 extends forward from the lower part of the engine 12 provided in the prime mover 2. The intermediate frame 9 is installed on the main clutch 13 connected to the lower rear end of the engine 12 and the transmission unit 4 disposed behind the main clutch 13. The rear frame 10 also serves as a transmission case for the transmission unit 4. The support frame 11 supports left and right support shafts 14 extending laterally outward from the left and right ends of the support frame 11. The left and right support shafts 14 are rotatably supported by left and right boss portions 11A fixed to the left and right ends of the support frame 11. The left and right support shafts 14 are fixed to the boss portion 11A by a positioning plate 15 fixed to the left and right intermediate portion of the support shaft 14 and a retaining member 16 that is bolted to the vehicle body inner end portion of the support shaft 14. Movement in the direction is blocked.

  Power from the engine 12 is transmitted to the transmission unit 4 via the main clutch 13 and the like. In the transmission unit 4, the power is branched into power for driving the front wheels, power for driving the crawler, and power for work. Power for driving the front wheels is transmitted to the left and right front wheels 5 via a front wheel drive unit (not shown) provided inside a front axle case (not shown). The power for driving the crawler is transmitted to the left and right crawlers 6 via the left and right drive shafts 17 extending from the transmission unit 4 to the left and right. The working power is taken out from the PTO shaft 18 extending rearward from the transmission unit 4.

  Left and right extension cases (not shown) that widen the tread of the left and right front wheels 5 are bolted to the front axle case 16. An extension shaft 20 that widens the tread of the left and right crawlers 6 is bolted to the left and right drive shafts 17. Thereby, this tractor is comprised by the onion specification which has a wide tread which can straddle the straw for onion cultivation.

  As shown in FIG. 1, the driving unit 3 includes a steering wheel 21 for front wheel steering, a driving seat 22 disposed behind the steering wheel 21, and the like.

  A link mechanism 23 is provided at the rear part of the transmission unit 4 to enable the work device to be attached. Thereby, working devices, such as a multi-rotary for hook forming, a seedling transplanting device for onions, and a root cutting device for onions, can be attached to the rear part of the tractor.

  As shown in FIGS. 1 to 5, the left and right crawlers 6 are swingably supported by a drive sprocket 30 that rotates integrally with a drive shaft 17 via an extension shaft 20 and a left and right support shaft 14. The track frame 31, the front idler 33 supported by the front end of the track frame 31 via the biasing mechanism 32, the rear idler 34 supported by the rear end of the track frame 31, and the front and rear intermediate portions of the track frame 31. Three crawler rollers 35 supported by a single crawler guide 36 and a crawler belt 37 that is rotated by the rotation of the drive sprocket 30 and guided by rotation by the front and rear idlers 33, 34, etc. ing.

With the above configuration, when the left and right crawlers 6 are undulated in the farm field, the front and rear idlers 33 and 34 that guide the rotation of the crawler belt 37 on the grounded side, the respective rolling wheels 35, etc. In accordance with the unevenness, it swings up and down together with the track frame 31 with the left and right support shafts 14 as fulcrums. Thereby, the ground contact side of the crawler belt 37 can be made to follow the ups and downs of the tiller, and regardless of the ups and downs of the tiller, the contact area of the left and right crawlers 6 is widened and the grip force of the left and right crawlers 6 is increased. . As a result, the running performance by the left and right crawlers 6 is enhanced.
Further, since the dedicated support shafts 14 that support the left and right track frames 31 so as to be swingable are provided, for example, the left and right drive shafts 17 are compared with the case where the left and right drive shafts 17 are also used as the support shafts 14. This burden can be reduced. Thereby, the durability of the left and right drive shafts 17 can be improved.

  As shown in FIGS. 1 to 5, in the left and right crawlers 6, the crawler belt 37 includes an endless belt-like rubber belt 37 </ b> A, a plurality of core bars 37 </ b> B embedded in the rubber belt 37, and the like. The plurality of core bars 37B are arranged so as to be arranged at regular intervals in the circumferential direction of the rubber belt 37A. A plurality of through holes 37 a formed between adjacent core bars 37 </ b> B and a plurality of passive portions 37 b including the core bars 37 </ b> B are arranged at a constant pitch in the circumferential direction of the crawler belt 37. Are alternately arranged. On the inner peripheral surface of the crawler belt 37, a plurality of guided projections 37 c including a core metal 37 </ b> B are formed to protrude at a constant pitch in the circumferential direction of the crawler belt 37 in two rows on the left and right.

  In the left and right crawlers 6, the drive sprocket 30 includes a first rotating body 38 that is bolted to the extension shaft 20, a ring-shaped second rotating body 39 that is bolted to the outer periphery of the first rotating body 38, and the like. It has. The first rotating body 38 is formed in a shape in which an inner peripheral portion that is bolt-connected to the extension shaft 20 is biased to the left or right with respect to the outer peripheral portion. The second rotating body 39 has two arcuate members 39A and is configured to be divided into two in the circumferential direction. A plurality of drive protrusions 39 a are formed on the outer periphery of the second rotating body 39 so as to protrude at a constant pitch. Each driving protrusion 39a enters the through hole 37a of the crawler belt 37 and presses the passive portion 37b when the crawler 6 is driven. By this pressing, the left and right drive sprockets 30 rotate the left and right crawler belts 37.

  In the left and right crawlers 6, the front idler wheel 33 and the rear idler wheel 34 are formed as inner rollers that enter between two left and right guided projections 37 c formed on the crawler belt 37. As a result, the front idler 33 and the rear idler 34 guide the crawler belt 37 in the rotational direction while preventing the front and rear ends of the crawler belt 37 from shifting in the left-right direction when the crawler 6 is driven.

  In the left and right crawlers 6, the respective rolling wheels 35 are arranged between the front idler wheel 33 and the rear idler wheel 34 with an interval in the front-rear direction. Each wheel 35 is formed as an outer wheel that straddles the left and right guided projections 37 c formed on the crawler belt 37. The crawler guide 36 has a front-rear length extending over the three rollers 35 and enters between the left and right guided projections 37 c formed on the crawler belt 37. Thus, each roller 35 and crawler guide 36 guides the crawler belt 37 in the rotation direction while preventing the front and rear intermediate portion of the crawler belt 37 from shifting in the left-right direction when the crawler 6 is driven.

  In the left and right crawlers 6, the track frame 31 includes a first member 41 that supports each wheel 35 and the crawler guide 36, and a second member 42 that is positioned at the front end of the first member 41 and supports the biasing mechanism 32. A third member 43 located at the rear end of the first member 41 and supporting the rear idler 34; a fourth member 44 installed between the second member 42 and the third member 43; and the like. Yes.

  In the left and right crawlers 6, the urging mechanism 32 includes a compression spring 45 that pushes the front idler wheel 33 forward and downward, a screw feed type adjustment unit 46 that adjusts the force of the compression spring 45 acting on the front idler wheel 33, and the like. I have. As a result, the biasing mechanism 32 can adjust the tension of the crawler belt 37 to an appropriate state by operating the adjusting unit 46, and the crawler belt 37 can be adjusted to the front and rear idlers 33 and 34 and the respective rolling wheels 35 by this adjustment. It can be made hard to come off.

  As shown in FIGS. 2 to 6, the tractor includes a left and right swing regulating mechanism 47 that regulates the swing of the left and right track frames 31 with the left and right support shafts 14 as fulcrums. The left and right swing regulating mechanisms 47 extend laterally outward of the support frame 11 from the positioning plate 15 that swings integrally with the track frame 31 via the support shaft 14 and the left end or right end of the support frame 11. The fixing member 48 is configured. The left and right positioning plates 15 are formed with openings 15A into which the extending portions of the fixing members 48 are inserted. The left and right swing restriction mechanism 47 restricts the forward downward swing of the track frame 31 when the upper portion of the positioning plate 15 contacts the extending portion of the fixing member 48. The left and right swing regulation mechanism 47 regulates the upward swing of the track frame 31 when the lower portion of the positioning plate 15 comes into contact with the extending portion of the fixing member 48.

  As shown in FIGS. 1 to 6, the tractor includes a tread changing unit 50 that changes the tread (wheel distance) of the left and right front wheels 5 and the left and right crawlers 6. The tread changing unit 50 includes a front tread changing unit (not shown) that changes the tread of the left and right front wheels 5 and a rear tread changing unit 52 that changes the tread of the left and right crawlers 6.

  Although illustration is omitted, the front tread changing portion 51 is configured by left and right spacers that are attached and detached between the left and right front axles and the left and right front wheels 5. Accordingly, the tread of the left and right front wheels 5 is directly connected to the outer end portions of the left and right front axles 24 by directly connecting the left and right front wheels 5 to the left and right front wheels 5 and the left and right front wheels 5 are By connecting to the outer end portions of the left and right front axles 24 via left and right spacers 53, it is possible to switch to the second tread in which the distance between the left and right front wheels 5 is increased.

  As shown in FIGS. 1 to 6, the rear tread changing unit 52 includes a sprocket position changing mechanism 54 that changes the positions of the left and right drive sprockets 30 with respect to the left and right extension shafts 20 in the left and right directions, and a left and right side with respect to the left and right support shafts 14. And a frame position changing mechanism 55 for changing the mounting position of the track frame 31 in the left-right direction.

  The sprocket position changing mechanism 54 is configured by a first rotating body 38 provided in the left and right drive sprockets 30. The first rotating body 38 is connected to the extension shaft 20 in a first posture in which the inner peripheral portion of the first rotating member 38 is located on the laterally outer side of the vehicle body from the outer peripheral portion, and the outer peripheral portion of the first rotating member 38 is in the inner position. It is possible to switch to the second posture that is located on the laterally outer side of the vehicle body from the periphery. In the left and right drive sprockets 30, the second rotating body 39 is in a position in contact with the outer periphery of the first rotating body 38 from the inside of the vehicle body regardless of the first and second attitudes of the first rotating body 38. A bolt is connected to the outer periphery of the one-rotor 38. That is, the left and right drive sprockets 30 are recombined into a first shape in which the connecting posture of the first rotating body 38 is the first posture and a second shape in which the connecting posture of the first rotating body 38 is the second posture. Can do.

  The sprocket position changing mechanism 54 is configured such that when the left and right drive sprockets 30 assembled in the first shape are bolted to the left and right extension shafts 20, the distance between the left and right second rotating bodies 39 is the same as that of the left and right front wheels 5. It is set to be a narrow interval corresponding to one tread. When the left and right drive sprockets 30 assembled in the second shape are bolted to the left and right extension shafts 20, the sprocket position changing mechanism 54 is configured so that the distance between the left and right second rotating bodies 39 is the same as that of the left and right front wheels 5. It is set to have a wide interval corresponding to 2 treads.

  The frame position changing mechanism 55 extends from the left and right track frames 31 so as to be connectable to the left and right first connecting members 56 and the left and right first connecting members 56 fixed to the ends of the left and right support shafts 14 on the track frame side. The left and right second connecting members 57, the left and right first connecting members 56 and the left and right second connecting members 57 are connected to each other by six sets of right and left connecting tools 58. Mounted surfaces 56 a are formed on the left and right first connecting members 56. The left and right second connecting members 57 are provided with mounting surfaces 57a. The left and right first connecting members 56 and the left and right second connecting members 57 are moved relative to the first connecting member 56 by sliding the second connecting member 57 in the left-right direction with respect to the first connecting member 56 along the placement surface 57a. The connection position of 2 connection member 57 is selected, and it has connecting parts 56b and 57b which enable connection with the 1st connection member 56 and the 2nd connection member 57 by connecting tool 58 in the selected connection position. Yes.

  In the case of changing the distance between the left and right track frames 31 with the above configuration, first, as a procedure, the connection between the first connection member 56 and the second connection member 57 by each connection tool 58 is released. Next, the second connecting member 57 is slid in the left-right direction along the placement surface 57 a together with the track frame 31 and the like to change the connecting position of the second connecting member 57 with respect to the first connecting member 56. Thereafter, the first connecting member 56 and the second connecting member 57 are connected by the respective connecting tools 58 while the mounting surface 57a and the mounting surface 56a are in surface contact at the changed connecting position.

  That is, the operator changes the connecting position of the second connecting member 57 with respect to the first connecting member 56, so that the left and right track frames 31 can be removed without inserting and removing the support shaft 14 with respect to the boss portion 11 </ b> A of the support frame 11. The interval can be changed.

  And since the 1st connection member 56 is being fixed to the edge part by the side of the track frame in the spindle 14, ie, the horizontal outer end side of the vehicle body in the spindle 14, the operator is with respect to the 1st connection member 56. The second connecting member 57 can be connected and disconnected from the lateral side of the vehicle body without difficulty.

  As a result, the interval between the left and right track frames 31 can be easily changed to an interval suitable for the left and right widths of different pods depending on the region to be cultivated, the type of crop, and the like.

  3-4, the connection position of the 2nd connection member 57 with respect to the 1st connection member 56 is the 1st connection position (refer FIG. 3) in which the 2nd connection member 5 approaches the vehicle body frame 1, and 2nd connection. The member 5 can be changed in two stages to a second connection position (see FIG. 4) where the member 5 is separated from the vehicle body frame 1. The frame position changing mechanism 55 is configured such that when the second connecting member 57 is connected to the first connecting position, the interval between the left and right track frames 31 is a narrow interval corresponding to the first tread of the left and right front wheels 5. Is set. The frame position changing mechanism 55 is configured such that when the second connecting member 57 is connected to the second connecting position, the distance between the left and right track frames 31 is a wide distance corresponding to the second tread of the left and right front wheels 5. Is set.

  With the above configuration, when narrowing the tread of the left and right crawlers 6, as a procedure, first, the rear portion of the vehicle body frame 1 is fixed at a height suitable for changing the tread of the crawler 6 using a jack or the like. To do. Next, the adjustment unit 46 of the urging mechanism 32 is operated to loosen the tension of the crawler belt 37, and the crawler belt 37 is removed from the drive sprocket 30 and the like. Then, the drive sprocket 30 is removed from the extension shaft 20, and the drive sprocket 30 is reassembled from the first shape to the second shape. In addition, after the connection between the first connecting member 56 and the second connecting member 57 by each connecting tool 58 is released, the second connecting member 57 is slid in the left-right direction along the mounting surface 57a together with the track frame 31 and the like. Then, the connection position of the second connection member 57 with respect to the first connection member 56 is changed from the first connection position to the second connection position. Thereafter, the first connecting member 56 and the second connecting member 57 are connected by the respective connecting tools 58 in a state where the mounting surface 56a and the mounting surface 57a are in surface contact at the second connecting position. Further, the second-shaped drive sprocket 30 is attached to the extension shaft 20, and the crawler belt 37 is attached to the drive sprocket 30 and the like. And after adjusting the tension | tensile_strength of the crawler belt 37 to an appropriate state by operating the adjustment part 46 of the urging | biasing mechanism 32, fixation of the vehicle body frame 1 by a jack etc. is cancelled | released.

  As a result, the tread of the left and right crawlers 6 can be changed to the first tread T1 in which the distance between the left and right crawlers 6 is reduced in the same manner as the first tread of the left and right front wheels 5 (see FIG. 3).

  Conversely, when widening the tread of the left and right crawlers 6, as a procedure, first, the rear portion of the vehicle body frame 1 is fixed at a height suitable for changing the tread of the crawler 6 using a jack or the like. Next, the adjustment unit 46 of the urging mechanism 32 is operated to loosen the tension of the crawler belt 37, and the crawler belt 37 is removed from the drive sprocket 30 and the like. Then, the drive sprocket 30 is removed from the extension shaft 20, and the drive sprocket 30 is reassembled from the second shape to the first shape. In addition, after the connection between the first connecting member 56 and the second connecting member 57 by each connecting tool 58 is released, the second connecting member 57 is slid in the left-right direction along the mounting surface 57a together with the track frame 31 and the like. Then, the connection position of the second connection member 57 with respect to the first connection member 56 is changed from the second connection position to the first connection position. Thereafter, the first connecting member 56 and the second connecting member 57 are connected by the respective connecting tools 58 in a state where the mounting surface 56a and the mounting surface 57a are in surface contact at the first connecting position. The drive sprocket 30 having the first shape is attached to the extension shaft 20, and the crawler belt 37 is attached to the drive sprocket 30 and the like. And after adjusting the tension | tensile_strength of the crawler belt 37 to an appropriate state by operating the adjustment part 46 of the urging | biasing mechanism 32, fixation of the vehicle body frame 1 by a jack etc. is cancelled | released.

  Thereby, the tread of the left and right crawlers 6 can be changed to the second tread T2 in which the distance between the left and right crawlers 6 is wide as in the second tread of the left and right front wheels 5 (see FIG. 4).

  That is, the treads of the left and right crawlers 6 are a first tread T1 suitable for work in a farm field having a narrow left and right width, and a second tread suitable for work in a farm field having a wide left and right width. It can be easily changed to the tread T2.

  As shown in FIGS. 2 to 6, the left and right first connecting members 56 connect the front and rear intermediate portions of the first steel plate 56 </ b> A and the first steel plate 56 </ b> A that form the placement surface 56 a to the support shaft 14. The front and rear second steel plates 56B and the third steel plates 56C that connect the lateral outer ends of the first steel plates 56A to the support shaft 14 are provided. The first steel plate 56A and the front and rear second steel plates 56B have a lateral width extending from the positioning plate 15 to the third steel plate 56C.

  The left and right second connecting members 57 are made of a steel plate, and are bent and formed in a U shape having standing portions 57c at both front and rear ends. The base end side of the second connecting member 57 is supported from below by the fourth member 44 of the track frame 31. That is, the fourth member 44 functions as a support member that supports the base end side of the second connecting member 57 from below. The fourth member 44 includes a substantially trapezoidal support plate 44A in side view and front and rear reinforcing plates 44B joined to the inner side surface of the support plate 44A. The front reinforcing plate 44 </ b> B is constructed from the second member 42 of the track frame 31 to the second connecting member 57. The rear reinforcing plate 44 </ b> B extends from the third member 43 of the track frame 31 to the second connecting member 57.

  Each connecting tool 58 is interposed between a nut 59 welded to a connecting portion forming portion of the second connecting member 57, a bolt 60 that can be screwed into the nut 59, and the second connecting member 56 and the bolt 60. A washer 61 is provided.

  As shown in FIGS. 5 to 6, in the left and right first connecting members 56, the connecting portions 56 b are formed in a total of eight positions formed at four positions spaced apart in the left-right direction on both front and rear ends of the first steel plate 56 </ b> A. It is composed of one round hole a. In the left and right second connecting members 57, the connecting portion 57 b is configured by a total of six second round holes b formed at three positions spaced apart in the left-right direction on both front and rear ends of the second connecting member 57. ing. That is, the left and right second connecting members 57 are formed with the same number (six) of second round holes b as the number of the connecting tools 58 (six sets), and the left and right first connecting members 56 have the connecting tools. A number (eight) of first round holes a are formed by adding 58 (six sets) and a number (two) corresponding to the tread change step number (two steps) of the left and right crawlers 6. The arrangement interval in the left-right direction of the first round holes a and the arrangement interval in the left-right direction of the second round holes b are set to half the tread change length of the left and right crawlers 6.

  With the above configuration, the number of the connecting tools 58 used for connecting the first connecting member 56 and the second connecting member 57 is the same regardless of the change in the connecting position of the second connecting member 57 with respect to the first connecting member 56. Become. Thereby, the connection strength of the 1st connection member 56 and the 2nd connection member 57 can be made the same irrespective of the change of a connection position.

  Moreover, compared with the case where a long hole is employ | adopted as the connection part 56b of the 1st connection member 56, the hole formation area in the 1st connection member 56 decreases. Thereby, the fall of the intensity | strength in the 1st connection member 56 resulting from providing the connection part 56b in the 1st connection member 56 can be suppressed.

  By the way, if the tread change step number of the left and right crawlers 6 is three, the left and right first connecting members 56 have the number of connecting members 58 (6 sets) and the tread change step number of the left and right crawlers 6 (three steps). The number (10 pieces) of first round holes a obtained by adding the corresponding number (four pieces) is formed.

  As shown in FIGS. 2 to 6, in the left and right second connecting members 57, the upright portions 57 c at the front and rear ends restrict the positional displacement of the second connecting member 57 in the front-rear direction with respect to the first connecting member 56. Function as.

  With this configuration, when the connecting position of the second connecting member 57 with respect to the first connecting member 56 is changed for changing the tread, the second connecting member 57 is slid in the left-right direction with respect to the first connecting member 56. It becomes easy. This makes it easier to change the distance between the left and right track frames 31 and makes it easier to change the tread of the left and right crawlers 6.

  As shown in FIGS. 3 to 4, in the left and right track frames 31, the fourth member 44 has a length in the left-right direction of the support region that supports the proximal end side of the second connecting member 57. It is set to be longer than the arrangement interval in the left-right direction. Regardless of the change in the connecting position of the second connecting member 57 with respect to the first connecting member 56, the left and right first connecting members 56 have the track frame side end on the placement surface 56a being the fourth on the placement surface 57a. The member (support member) 44 is configured to be located within the support region.

  With the above configuration, regardless of the change in the connection position of the second connection member 57 with respect to the first connection member 56, the first connection member 56 is the end of the mounting surface 56 a on the track frame side, that is, the mounting surface. The end of the vehicle body laterally outside on the surface 56a is received and supported from below by the fourth member 44 of the track frame 31 via the base end side of the second connecting member 57.

  As a result, regardless of the change of the connection position of the second connection member 57 with respect to the first connection member 56, the first connection member 56 on the vehicle body frame side is preferably received with good stability from below by the fourth member 44 on the crawler side. Can be supported.

[Another embodiment]
The present invention is not limited to the configuration exemplified in the above-described embodiment, and typical other embodiments relating to the present invention will be exemplified below.

[1] The configuration exemplified below may be adopted for the work vehicle.
For example, the work vehicle may be configured in a full crawler specification including only the left and right crawlers 6 without including the left and right front wheels 5.
For example, the work vehicle may be configured to have an electric specification including an electric motor instead of the engine 12.
For example, the work vehicle may be configured in a hybrid specification including the engine 12 and an electric motor.

[2] The configuration of the body frame 1 can be variously changed.
For example, the vehicle body frame 1 may include left and right side members extending from the front and rear ends of the vehicle body, and a plurality of cross bars extending from the left and right side members.

[3] The configuration of the left and right crawlers 6 can be variously changed.
For example, the left and right crawlers 6 may be configured such that the drive sprocket 30 is directly connected to the left and right drive shafts 17 extending from the transmission unit 4 to the left and right.
For example, the left and right crawlers 6 may be formed integrally with the first rotating body 38 and the second rotating body 39 of the drive sprocket 30.
For example, the left and right crawlers 6 may be formed in a ring shape in which the second rotating body 39 of the drive sprocket 30 cannot be divided in the circumferential direction.
For example, the left and right crawlers 6 may be configured such that the second rotating body 39 of the drive sprocket 30 can be divided into three in the circumferential direction.
For example, the left and right crawlers 6 are not provided with a plurality of through holes 37 a in the crawler belt 37, and each passive portion 37 b of the crawler belt 37 protrudes from the inner peripheral surface of the crawler belt 37. It may be formed at a constant pitch in the direction.
For example, the left and right crawlers 6 swing up and down in a fixed posture by the track frame 31 supported by the front and rear support shafts 14 extending left and right from the vehicle body frame 1 via swing arms. It may be configured.
For example, the left and right crawlers 6 may be configured such that the support member (fourth member) 44 of the track frame 31 includes only a substantially trapezoidal support plate 44A in side view. In this configuration, the front and rear reinforcement portions corresponding to the front and rear reinforcement plates 44B exemplified in the above embodiment are formed by bending the support plate 44A so that both front and rear ends of the support plate 44A are directed left and right. 44A can be integrally formed.

[4] The configuration of the tread changing unit 50 can be variously changed according to the configuration of the work vehicle.
For example, when the work vehicle is configured to the full crawler specification, the tread change unit 50 is configured to the full crawler specification that changes only the tread of the left and right crawlers 6.
For example, the tread changing unit 50 may include a left and right spacer in which the sprocket position changing mechanism 54 is attached and detached between the left and right extension shafts 20 and the left and right drive sprockets 30.
For example, the tread changing unit 50 may be configured to change the treads of the left and right crawlers 6 in a stepless manner.
For example, the tread changing unit 50 may be configured to be able to change the tread of the left and right crawlers 6 in three or more stages.

[5] The configuration of the frame position changing mechanism 55 can be variously changed.
For example, the frame position changing mechanism 55 may have a mounting surface formed on the first connecting member 56 and a mounting surface formed on the second connecting member 57.
For example, in the frame position changing mechanism 55, one of the connecting portion 56b of the first connecting member 56 and the connecting portion 57b of the second connecting member 57 may be configured by a long hole that is long in the left-right direction.
For example, in the frame position changing mechanism 55, the first round holes a having the same number as the number of the coupling tools 58 are formed in the left and right first coupling members 56, and the number of the coupling tools 58 is formed in the left and right second coupling members 57. A second round hole b may be formed by adding a quantity corresponding to the number of tread change steps of the left and right crawlers 6. Note that the number of the coupling tools 58 and the like can be variously changed according to the weight of the track frame 31 and the like.
For example, the frame position changing mechanism 55 may include a restricting portion 57 c that restricts the positional displacement of the second connecting member 57 in the front-rear direction with respect to the first connecting member 56 in the left and right first connecting members 56.
For example, in the frame position changing mechanism 55, the nut 59 of each connecting tool 58 may be welded to the connecting portion forming portion of the first connecting member 56.

  The present invention can be applied to work vehicles such as a semi-crawler specification tractor, a full crawler specification tractor, a seedling transplanting harvester, a harvesting machine, and a backhoe, which are configured to be able to change the tread of the left and right crawlers.

DESCRIPTION OF SYMBOLS 1 Body frame 4 Transmission unit 6 Crawler 14 Support shaft 17 Drive shaft 30 Drive sprocket 31 Track frame 33 Front idler 34 Rear idler 35 Roller 37 Crawler belt 44 Support member 50 Tread change unit 55 Frame position change mechanism 56 First connection member 56a Placed surface 56b Connection portion 57 Second connection member 57a Placement surface 57b Connection portion 57c Restriction portion (standing portion)
58 connector a 1st round hole b 2nd round hole

Claims (4)

Left and right crawlers arranged on the left and right of the body frame, left and right drive shafts extending left and right from the transmission unit, left and right support shafts extending left and right from the body frame, and treads of the left and right crawlers With tread change unit to change,
The crawler includes a drive sprocket that rotates integrally with the drive shaft, a track frame that is swingably supported by the body frame via the support shaft, and a front idler that is supported by a front end portion of the track frame, A rear idler supported by the rear end of the track frame, a plurality of wheels supported by the front and rear intermediate parts of the track frame, and rotated by the rotation of the drive sprocket; A crawler belt that is pivotally guided by the wheel,
The tread changing unit includes a frame position changing mechanism that changes a mounting position of the track frame with respect to the support shaft in a left-right direction,
The frame position changing mechanism includes a first connecting member fixed to an end of the support shaft on the track frame side, a second connecting member extending from the track frame so as to be connectable to the first connecting member, A plurality of couplers for coupling the first coupling member and the second coupling member;
A mounting surface is formed on one of the first connecting member and the second connecting member, and the mounting surface is mounted on the other of the first connecting member and the second connecting member. A mounting surface is formed,
The first connecting member and the second connecting member may be configured such that the second connecting member with respect to the first connecting member is slid in the left-right direction of the second connecting member with respect to the first connecting member along the placement surface. A work vehicle comprising a connecting portion that enables connection between the first connecting member and the second connecting member by the connecting tool at the selected connecting position. The connecting portion of the first connecting member is constituted by a plurality of first round holes formed at regular intervals in the left-right direction in the first connecting member,
The connecting portion of the second connecting member is configured by a plurality of second round holes formed at regular intervals in the left-right direction in the second connecting member,
The arrangement interval of the first round hole and the second round hole is set to a half length with respect to the change length of the tread,
The quantity of one of the first round hole and the second round hole is the same quantity as the quantity of the connector, and the quantity of the other of the first round hole and the second round hole is The work vehicle according to claim 1, wherein the work vehicle is a quantity obtained by adding a quantity corresponding to the number of steps of the tread to the quantity of the coupling tool.   The regulation part which regulates the position shift to the front-back direction of the 2nd connecting member with respect to the 1st connecting member is provided in either one of the 1st connecting member and the 2nd connecting member. Work vehicle as described in. The mounting surface is formed on the first connecting member, and the mounting surface is formed on the second connecting member;
The track frame includes a support member that supports a base end side of the second connecting member from below.
Regardless of the change in the connection position of the second connection member with respect to the first connection member, the end portion on the track frame side of the placement surface is located within the support region of the support member on the placement surface. The work vehicle according to any one of claims 1 to 3.

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