Travel device for work vehicle, and work vehicle

Abstract

The present invention provides a travel device for a work vehicle and a work vehicle in which a force that deforms a main shaft member is less likely to be applied to the main shaft member. A travel device (3) for a work vehicle is provided with a pressing device (41), a support member (45), a pair of coupling members (46), and a breaking mechanism (47). The pressing device (41) includes a main shaft member (411) having a length in a predetermined direction, and presses the pressing member (412) in one direction of the predetermined direction by means of the main shaft member (411). The support member (45) supports one end of the main shaft member (411). The pair of coupling members (46) couple the support member (45) and the fixing member (48). When one of the pair of coupling members (46) is broken, the breaking mechanism (47) causes a force for breaking the other coupling member (46) to act on the other coupling member (46) before a force for deforming the main shaft member (411) acts on the main shaft member (411).

Description

Technical Field

[0001] The present invention relates to a travel device of a working vehicle and a working vehicle including a pressing device for pressing a pressing member in a predetermined direction using a main shaft member. Background Art

[0002] As a related art, the following (track) travel device is known, which is used for a working vehicle such as a combine harvester, and includes a tension frame (tension adjustment frame) that can be displaced in the front-rear direction relative to the track frame, and a tension roller (track tension adjustment wheel) supported on the tension frame (for example, refer to Patent Document 1). With respect to the travel device, the tension frame includes: a main frame that can be moved in the front-rear direction relative to the track frame; and a wheel body support body that supports the tension roller. The wheel body support body can be displaced between a normal connection position in which the tension roller is located at an adjustment position based on a main shaft component (tension adjustment screw shaft), and an abnormal connection position in which the tension roller is moved to a position closer to the track slack side than the adjustment position.

[0003] The travel device also includes a holding mechanism that can switch between a non-destructive state in which the wheel support body is held at a normal connection position and a destructive state in which the wheel support body is released from the normal connection position. With respect to the holding mechanism, if the track tension acting on the tension roller is less than the set tension, the safety pin is not broken and is in a non-destructive state, and if the track tension acting on the tension roller reaches or exceeds the set tension, the safety pin is broken and switched to a destructive state. Therefore, if an excessive track tension acts on the tension roller, the safety pin is broken and the wheel support body is switched to an abnormal connection position, and the tension roller moves to the loose track side to reduce the track tension.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2009-292338 Summary of the invention

[0007] Regarding the structure of the above-mentioned related art, when the load applied to the safety pin is unstable, for example, when the track passes over a protrusion, when excessive external force is applied to the tension roller, a force that causes the main shaft component to deform may be applied to the main shaft component.

[0008] An object of the present invention is to provide a travel device for a work vehicle and a work vehicle in which a force that deforms a main shaft member is less likely to be applied to the main shaft member.

[0009] The travel device of a working vehicle according to one aspect of the present invention comprises a pressing device, a supporting member, a pair of connecting members, and a breaking mechanism. The pressing device includes a main shaft member having a length in a predetermined direction, and the main shaft member is used to press the pressing member in one direction of the predetermined direction. The supporting member supports one end of the main shaft member. The pair of connecting members connect the supporting member to a fixing member. The breaking mechanism causes a force that causes the other connecting member to break to act on the other connecting member before a force that causes the main shaft member to deform acts on the main shaft member when one connecting member of the pair of connecting members breaks.

[0010] A work vehicle according to one aspect of the present invention includes: a travel device of the work vehicle; and a platform supported by the travel device so as to be travelable.

[0011] Effects of the Invention

[0012] According to the present invention, it is possible to provide a travel device for a work vehicle and a work vehicle in which a force that deforms a main shaft member is less likely to be applied to the main shaft member. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic left side view of the work vehicle according to the first embodiment.

[0014] Figure 2 This is a schematic perspective view of a chassis frame and a travel device of a work vehicle according to the first embodiment.

[0015] Figure 3 This is a schematic perspective view of the travel device of the work vehicle according to the first embodiment.

[0016] Figure 4 This is a schematic perspective view of a state in which a crawler track of a travel device of a work vehicle according to Embodiment 1 is removed.

[0017] Figure 5 This is a schematic left side view of the travel device of the work vehicle according to the first embodiment.

[0018] Figure 6 This is a schematic left side view of a state where the crawler track of the travel device of the work vehicle according to the first embodiment is removed.

[0019] Figure 7 This is an enlarged perspective view of the periphery of the tension adjustment device of the travel device of the work vehicle according to the first embodiment.

[0020] Figure 8 This is an enlarged perspective view of the periphery of the tension adjustment device of the travel device of the work vehicle according to the first embodiment.

[0021] Fig. 9 This is an enlarged left side view of the periphery of the tension adjustment device of the travel device of the work vehicle according to the first embodiment.

[0022] Fig.10 This is an enlarged plan view of the periphery of the tension adjustment device of the travel device of the work vehicle according to the first embodiment.

[0023] Fig.11 It is a partially cutaway perspective view of the periphery of the tension adjustment device of the travel device of the work vehicle according to the first embodiment.

[0024] Fig.12 It is a cross-sectional view of the periphery of the tension adjustment device of the travel device of the work vehicle according to the first embodiment.

[0025] Fig.13 It is a partially cutaway perspective view of the periphery of the tension adjustment device of the travel device of the work vehicle according to the first embodiment.

[0026] Fig.14 It is a cross-sectional view of the periphery of the tension adjustment device of the travel device of the work vehicle according to the first embodiment.

[0027] Fig.15 It is a cross-sectional view of the periphery of the tension adjustment device of the travel device of the work vehicle according to the first embodiment.

[0028] Fig.16 It is a partially cutaway perspective view of the periphery of the tension adjustment device of the travel device of the work vehicle according to the first embodiment.

[0029] Fig.17 It is a cross-sectional view of the periphery of the tension adjustment device of the travel device of the work vehicle according to the first embodiment.

[0030] Description of Reference Numerals

[0031] 1…operating vehicle; 2…machine platform; 3…traveling device; 32…track frame; 36…tension roller; 42…guide frame; 43…tension frame; 45…support component; 46…joining component; 47…breaking mechanism; 48…fixing component; 41…pressing device; 411…spindle component; 412…pressing component; 451…through hole; G1…gap; D2…front and rear direction. DETAILED DESCRIPTION

[0032] The following is an explanation of an embodiment of the present invention with reference to the drawings. The following embodiment is an example of implementing the present invention, and its purpose is not to limit the technical scope of the present invention.

[0033] (Implementation Method 1)

[0034] [1] Overall structure

[0035] First, refer to Figure 1 The overall structure of the work vehicle 1 according to the present embodiment will be described.

[0036] The "operation vehicle" mentioned in the present disclosure refers to a machine that performs various operations in the target area F1 such as a field, for example, agricultural machinery (agricultural machinery) such as a harvester, a tractor, a seed drill, a rice transplanter, a spreader, a sprayer, and a transplanter. The operation vehicle 1 can also be, for example, a construction machine (construction machine). The "operation" mentioned in the present disclosure is the work performed by the operation vehicle 1 on the target area F1, for example, including various agricultural operations such as harvesting, leveling, sowing, fertilizing, spreading pesticides, or planting (transplanting), as well as various operations such as construction operations.

[0037] In this embodiment, unless otherwise stated, the working vehicle 1 is a machine for harvesting crops in the target area F1. More specifically, a combine harvester that performs threshing and screening on the basis of harvesting is cited as an example for explanation. The combine harvester as the working vehicle 1 is mainly used for harvesting grains, and harvests the harvested crops while moving (traveling) in the target area F1. In particular, there are ordinary (general) combine harvesters that send all the harvested crops to the thresher (thresher device 12) and self-threshing combine harvesters that only send the ears of the harvested crops to the thresher. In this embodiment, the ordinary combine harvester is described as an example of the working vehicle 1. In addition, in this embodiment, as an example, the working vehicle 1 performs actions by the operation (including remote operation) of a person (operator), but it is not limited to this. The working vehicle 1 can also be a drone that performs actions by automatic driving.

[0038] The "target area" mentioned in the present disclosure is an area where the work vehicle 1 performs various operations such as harvesting, leveling, sowing, fertilizing, spreading pesticides or planting (transplanting) while driving, including rice fields, dry fields, orchards and pastures. For example, when a rice field or dry field where crops (agricultural products) such as rice, wheat, soybeans or buckwheat are grown and cultivated is the target area F1, the crops cultivated in the target area F1 are agricultural products. In addition, when flowers and trees are grown and cultivated in a plantation, the plantation becomes the target area F1, and when trees that become wood are grown and cultivated in a forest as in forestry, the forest becomes the target area F1. In this case, the crops grown and cultivated in the target area F1 are flowers and trees or trees. In this embodiment, unless otherwise stated, the following case is cited as an example for explanation: the harvesting object of the work vehicle 1 is "rice", and the target area F1 is a rice field as a field where rice is grown and cultivated. In addition, the target area F1 is not limited to a field. For example, if the work vehicle 1 is a construction machine, the site where the construction machine performs operations becomes the target area F1.

[0039] In this embodiment, for the sake of convenience, the vertical direction when the work vehicle 1 is in a usable state is defined as the up-down direction D1. The front-rear direction D2 and the left-right direction D3 are defined based on the direction viewed from the person (operator) riding on the work vehicle 1 (the driving unit 16) (refer to Figure 2 ). The left side of the left-right direction D3 refers to the left side when the work vehicle 1 is moving forward (advancing), and the right side of the left-right direction D3 refers to the right side when the work vehicle 1 is moving forward (advancing). However, the purpose of these directions is not to limit the use direction (direction when in use) of the work vehicle 1.

[0040] The work vehicle 1 includes a platform 2 and a travel device 3 (of the work vehicle 1). In the present embodiment, the work vehicle 1 is a harvesting machine, and therefore, it also includes a harvesting device 11, a threshing device 12, a screening device 13, a storage device 14, a power device 15, and a driving unit 16. In addition, in the present embodiment, the work vehicle 1 also includes a control device, a communication terminal, a display device, a fuel tank, a battery, and various sensors.

[0041] The machine 2 has a chassis frame 21 (see Figure 2 ) and constitute the body of the working vehicle 1. The platform 2 is equipped with a threshing device 12, a screening device 13, a storage device 14, a power device 15, a driving unit 16, etc.

[0042] The travel device 3 supports the machine 2 so that it can travel. That is, the machine 2 equipped with the threshing device 12, the screening device 13, the storage device 14, the power device 15 and the driving part 16 is supported by the travel device 3 so that it can move (travel) in the target area F1. The travel device 3 is a device (vehicle body) that enables the machine 2 to travel. The machine 2 uses the travel device 3 to travel on the travel surface Fs1 (including turning) and can move in the target area F1 along the front-to-back direction D2 and the left-to-right direction D3. The "travel surface" mentioned in the present disclosure is the surface (ground) for the working vehicle 1 to travel, including the field surface and the paved road surface. In this embodiment, the following situation is taken as an example: the field surface that is the surface of the target area F1 composed of the field is the travel surface Fs1. The working vehicle 1 is equipped with such a travel device 3 and can perform operations (harvesting operations) while moving in the target area F1. As an example, the work vehicle 1 may move while turning leftward from the outside to the inside in the target area F1. In this case, the travel path of the work vehicle 1 is a spiral path that rotates counterclockwise in a plan view.

[0043] Specifically, the travel device 3 includes a pair of crawlers 31 arranged in the left-right direction D3. As an example, the pair of crawlers 31 includes a hydraulic actuator such as a hydraulic motor, and is driven by the power from the power device 15 in a state capable of independently changing speeds. Therefore, with respect to the machine 2, the pair of crawlers 31 are driven at a constant speed in the forward direction to form a forward state of moving straight forward, and the pair of crawlers 31 are driven at a constant speed in the backward direction to form a backward state of moving straight backward. In addition, with respect to the machine 2, the pair of crawlers 31 are driven at unequal speeds in the forward direction to form a forward turning state of turning while moving forward, and the pair of crawlers 31 are driven at unequal speeds in the backward direction to form a backward turning state of turning while moving backward. In addition, with respect to the machine 2, when the driving of one of the pair of crawlers 31 is stopped, the other crawler is driven to form a pivot turn (on-site turn) state, and the pair of crawlers 31 are driven at the same speed in the forward direction and the backward direction to form a self-rotation turn (center turn) state. In addition, the driving of the pair of crawlers 31 is stopped to make the machine 2 in a travel stop state.

[0044] The column “[3] Configuration of traveling device” describes the more detailed configuration of the traveling device 3 .

[0045] The harvesting device 11 harvests crops (rice in this embodiment, for example) on the travel surface Fs1 (field surface in this embodiment). The harvesting device 11 is arranged in front of the platform 2 of the work vehicle 1 and is connected to the platform 2. Here, the harvesting device 11 is supported on the platform 2 in a manner that allows it to be raised and lowered. In other words, the relative height (relative height) of the harvesting device 11 relative to the platform 2 is not fixed, and it is changed by driving the harvesting device 11 to be raised and lowered.

[0046] The harvesting device 11 includes a cutter (cutter). In the present embodiment, the harvesting device 11 is a harvesting device having a six-row harvesting width as an example. The stalks of the crop harvested by the harvesting device 11 are conveyed to the threshing device 12.

[0047] The threshing device 12 performs threshing processing on the crops (ear stalks) harvested by the harvesting device 11. In the threshing processing, threshed materials including grains are separated from the ear stalks. The threshed materials fall from the threshing device 12 to the screening device 13 below.

[0048] The screening device 13 performs a screening process for screening grains with respect to the threshed materials dropped from the threshing device 12. The screening device 13 screens the grains from the threshed materials by blowing air to the threshed materials from obliquely below, for example, and sieving the threshed materials.

[0049] The storage device 14 includes a grain box 141 and a discharge auger 142. The grain box 141 stores the grains transported from the screening device 13 by the transport conveyor. That is, the grains screened by the screening device 13 are transported to the grain box 141 by the transport conveyor and stored in the grain box 141. The discharge auger 142 discharges the grains in the grain box 141 to any place around the work vehicle 1.

[0050] The power device 15 supplies power to the travel device 3, the harvesting device 11, the threshing device 12, the screening device 13, the storage device 14, etc. The power device 15 has an engine such as a diesel engine as a power source. In addition, the power device 15 can have a motor (electric motor) as a power source, and can also have a hybrid power source including an engine and a motor. The power device 15 drives a hydraulic pump using a power source such as an engine to supply working oil from the hydraulic pump to hydraulic actuators (including hydraulic motors and hydraulic cylinders, etc.) of various parts of the work vehicle 1, thereby supplying power to various parts of the work vehicle 1.

[0051] The driving unit 16 is provided with a driving seat for a user (operator) to sit on, and operating devices such as a steering wheel, various operating levers, and various operating switches operated by the user. In the present embodiment, as an example, the driving unit 16 is a cab type having a cab 161, and the user rides in the cab space inside the cab 161.

[0052] The control device uses a computer system having one or more processors such as a CPU (Central Processing Unit) and one or more memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory) as a main structure to perform various processes (information processing). In the present embodiment, the control device uses a computer system having one or more processors as a main structure, so one or more processors execute a control program for the work vehicle to implement the control device. In the present embodiment, the control device is an integrated controller that controls the entire work vehicle 1, for example, it is composed of an electronic control unit (ECU: Electronic Control Unit). However, the control device can also be set to be different from the integrated controller.

[0053] [2] Machine structure

[0054] Next, refer to Figure 1 and Figure 2 The structure of the machine platform 2 of the work vehicle 1 according to the present embodiment will be described in detail.

[0055] The machine 2 has a chassis frame 21 as a structural body. The chassis frame 21 is a frame that supports the threshing device 12, the screening device 13, the storage device 14, the power device 15, the driving part 16, etc. Figure 2 The illustration of the threshing device 12 and the like mounted on the platform 2 (chassis frame 21) is omitted. The chassis frame 21 is formed by combining a plurality of frame components (such as metal pipes, etc.). In the present embodiment, the chassis frame 21 is extended in a planar shape along a horizontal plane to form a platform. Regarding the chassis frame 21, the threshing device 12, the screening device 13, the storage device 14, the power device 15, and the driving part 16 are mounted on the chassis frame 21. Moreover, the traveling device 3 is utilized to move the platform 2 together with the chassis frame 21 within the target area F1. Therefore, the chassis frame 21 has sufficient strength (rigidity) required to support heavy objects such as the threshing device 12.

[0056] Specifically, the chassis frame 21 includes a plurality of frame members, such as a left frame 211, a right frame 212, a front frame 213, a rear frame 214, a pair of longitudinal frames 215 and 216, and three transverse frames 217, 218, and 219. The plurality of frame members constituting the chassis frame 21 are fixed to each other by, for example, welding, bonding, or fastening with fasteners.

[0057] The left frame 211 and the right frame 212 each have a length in the front-to-back direction D2. The left frame 211 and the right frame 212 are separated and arranged in the left-to-right direction D3 in such a manner that the left frame 211 is located on the left. The front frame 213 has a length in the left-to-right direction D3, and connects the front portions of the left frame 211 and the right frame 212 to each other. The rear frame 214 has a length in the left-to-right direction D3, and connects the rear portions of the left frame 211 and the right frame 212 to each other. Thus, the left frame 211, the right frame 212, the front frame 213, and the rear frame 214 constitute a rectangular (oblong) frame outer frame having a length in the front-to-back direction D2 when viewed from above.

[0058] The pair of longitudinal frames 215 and 216 each have a length in the front-to-back direction D2. The pair of longitudinal frames 215 and 216 are separated and arranged in the left-right direction D3 between the left frame 211 and the right frame 212 in such a manner that the longitudinal frame 215 is located on the left. The front ends of the pair of longitudinal frames 215 and 216 are connected to the front frame 213, and the rear ends of the pair of longitudinal frames 215 and 216 are connected to the rear frame 214. The three transverse frames 217, 218, and 219 each have a length in the left-to-back direction D3. The three transverse frames 217 to 219 are separated and arranged in the order of transverse frame 217, transverse frame 218, and transverse frame 219 from the front in the front-to-back direction D2 between the front frame 213 and the rear frame 214. The left ends of the three transverse frames 217 to 219 are connected to the left frame 211, and the right ends of the three transverse frames 217 to 219 are connected to the right frame 212.

[0059] [3] Structure of the travel device

[0060] Next, refer to Figure 2 to Figure 6 The structure of the travel device 3 of the work vehicle 1 according to the present embodiment will be described in detail. Figure 3 Hereinafter, illustration of the machine table 2 (including the chassis frame 21 ) and the like will be omitted.

[0061] The travel device 3 includes: a first travel body 301 including one crawler of a pair of crawlers 31; and a second travel body 302 including the other crawler of the pair of crawlers 31. In the present embodiment, the first travel body 301 includes the crawler 31 on the left side of the pair of crawlers 31 arranged in the left-right direction D3, and the second travel body 302 includes the crawler 31 on the right side. That is, the first travel body 301 and the second travel body 302 are arranged in the left-right direction D3.

[0062] The first traveling body 301 receives power from the power device 15 and drives the crawler 31 on one side (the left side in this embodiment). The second traveling body 302 receives power from the power device 15 and drives the crawler 31 on the other side (the right side in this embodiment). Thus, the traveling device 3 independently drives a pair of crawlers 31 to realize the above-mentioned forward state, backward state, forward turning state, backward turning state, pivot turning (in-place turning) state, and self-rotation turning (center turning) state.

[0063] The first traveling body 301 and the second traveling body 302 are connected to each other by a connecting member 303. The connecting member 303 is a frame member having a length in the left-right direction D3, and both ends of the length direction thereof are extended downward to form a generally U-shaped shape that is open downward. The left end of the connecting member 303 is connected to the first traveling body 301, and the right end of the connecting member 303 is connected to the second traveling body 302. In the present embodiment, the traveling device 3 has a pair of connecting members 303 separated in the front-rear direction D2. Therefore, the first traveling body 301 and the second traveling body 302 are connected (connected) to each other by connecting members 303 at the front end and the rear end, respectively.

[0064] like Figure 2 As shown, a pair of connecting members 303 is combined with the chassis frame 21 of the machine 2. Specifically, the front connecting member 303 of the pair of connecting members 303 is mounted between the front ends of the pair of longitudinal frames 215 and 216 to connect the front ends of the pair of longitudinal frames 215 and 216 to each other. The rear connecting member 303 of the pair of connecting members 303 is mounted between the central portions of the pair of longitudinal frames 215 and 216 in the longitudinal direction (front-rear direction D2) to connect the central portions of the pair of longitudinal frames 215 and 216 to each other. In other words, the connecting member 303 is a frame cross member, and is fixed to the chassis frame 21 (a pair of longitudinal frames 215 and 216) by, for example, welding, bonding, or fastening with fasteners. Thus, the machine 2 is supported by the travel device 3 so as to be able to travel.

[0065] However, the first traveling body 301 and the second traveling body 302 have the same structure and are arranged symmetrically in the left-right direction D3. Therefore, hereinafter, unless otherwise stated, the structure of the traveling device 3 is described by taking the first traveling body 301 as an example, and the structure of the second traveling body 302 is the same as (symmetrical to) that of the first traveling body 301, and the description thereof is omitted.

[0066] The travel device 3 (first travel body 301) has a track frame 32. The track frame 32 has a length in the front-rear direction D2. The track frame 32 is directly or indirectly fixed to the above-mentioned connecting member 303. Specifically, the front connecting member 303 of the pair of connecting members 303 is connected to the front end of the track frame 32, and the rear connecting member 303 is connected to the rear end of the track frame 32. That is, the travel device 3 fixes the track frame 32 to the chassis frame 21 of the machine 2 by means of the connecting member 303 to support the machine 2.

[0067] Track frame 32 is disposed inside crawler track 31 and rotatably supports crawler track 31. Track frame 32 supports the weight of work vehicle 1 so that a grounding portion (lower portion) of crawler track 31 in contact with travel surface Fs1 is pressed against travel surface Fs1.

[0068] The travel device 3 (first travel body 301) includes a drive sprocket 33, a plurality of (two as an example) load rollers (upper rollers) 34, a plurality of (six as an example) track rollers (lower rollers) 35, and a tension roller 36 in addition to the crawler 31 and the crawler frame 32. The drive sprocket 33, the plurality of load rollers 34, the plurality of track rollers 35, and the tension roller 36 are directly or indirectly supported by the crawler frame 32 in a state of being rotatable around a rotation axis along the left-right direction D3.

[0069] The crawler 31 is a crawler formed of rubber, metal, or a combination of rubber and metal and formed into an annular shape. The crawler 31 is wound around the outer circumference of the crawler frame 32 so as to surround the drive sprocket 33, the plurality of carrier rollers 34, the plurality of crawler rollers 35, and the tension roller 36 supported by the crawler frame 32. Thus, the drive sprocket 33, the plurality of carrier rollers 34, the plurality of crawler rollers 35, and the tension roller 36 contact the inner circumference of the crawler 31 from the inner side of the crawler 31 to support the crawler 31.

[0070] The drive sprocket 33 is arranged at the upper and oblique front of the crawler frame 32. Specifically, the drive sprocket 33 is rotatably supported by the terminal end (front end) of the bearing frame 321 extending obliquely upward and frontward from the front connecting member 303 (the supporting structure of the drive sprocket 33 is omitted from the figure). In other words, the drive sprocket 33 is indirectly supported by the front end of the crawler frame 32 via the connecting member 303 and the bearing frame 321.

[0071] A plurality of carrier rollers 34 are disposed above the track frame 32. Specifically, two carrier rollers 34 are disposed above the track frame 32 so as to be separated in the front-rear direction D2. The front carrier roller 34 of the two carrier rollers 34 is rotatably supported by a support stand 322 provided on the upper surface of the track frame 32, and the rear carrier roller 34 is rotatably supported by a guide frame 42, which will be described later and is fixed to the track frame 32. That is, the plurality of carrier rollers 34 are indirectly supported by the track frame 32 via the support stand 322 or the guide frame 42.

[0072] A plurality of track rollers 35 are disposed below the track frame 32. Specifically, six track rollers 35 are disposed below the track frame 32 so as to be separated in the front-rear direction D2. The track roller 35 located at the rear of the six track rollers 35 is rotatably supported by a bracket 323 (see FIG. 1 ) fixed to the track frame 32 and described later. Fig.11 ), the remaining five track rollers 35 are directly supported on the track frame 32 in a rotatable manner. In other words, the plurality of track rollers 35 are indirectly or directly supported on the track frame 32 with or without the aid of the bracket 323.

[0073] The tension roller 36 is arranged at the rear of the crawler frame 32. Specifically, the tension roller 36 is rotatably supported by a terminal end (rear end) of a tension frame 43 described later extending rearward from the rear end of the crawler frame 32. That is, the tension roller 36 is indirectly supported by the rear end of the crawler frame 32 via the tension frame 43.

[0074] However, the travel device 3 (first travel body 301 ) includes a tension adjustment device 4 . The tension adjustment device 4 includes a guide frame 42 , a tension frame 43 , and a tension roller 36 , and is a device for adjusting the tension (tension force) applied to the crawler belt 31 .

[0075] Regarding the tension adjustment device 4, the tension frame 43 is configured to be movable relative to the track frame 32 in the longitudinal direction of the track frame 32. In the present embodiment, the track frame 32 has a length in the front-rear direction D2. That is, the tension frame 43 is displaceable relative to the track frame 32 in the front-rear direction D2. Moreover, the tension frame 43 is displaced in the front-rear direction D2, thereby causing the tension roller 36 supported by the tension frame 43 to also be displaced in the front-rear direction D2, and as a result, the tension applied to the crawler 31 changes.

[0076] In the present embodiment, as an example, the tension roller 36 is located behind the track frame 32. Therefore, as the tension frame 43 moves relatively backward with respect to the track frame 32, the pressing force of the tension roller 36 pressing on the track 31 increases (increases), thereby increasing (tightening) the tension acting on the track 31. On the other hand, as the tension frame 43 moves relatively forward with respect to the track frame 32, the pressing force of the tension roller 36 pressing on the track 31 decreases (weakens), thereby decreasing (loosening) the tension acting on the track 31.

[0077] The column “[4] Structure of the tension adjusting device” describes the structure of the tension adjusting device 4 in more detail.

[0078] As described above, travel device 3 includes bearing frame 321 , support stand 322 , bracket 323 , guide frame 42 , tension frame 43 , and the like as components for supporting drive sprocket 33 , multiple carrier rollers 34 , multiple track rollers 35 , and tension roller 36 .

[0079] According to the structure described above, the travel device 3 drives the crawler 31 to rotate by driving the drive sprocket 33 that contacts the crawler 31 from the inside using the power from the power device 15. At this time, the plurality of carrier rollers 34, the plurality of crawler rollers 35, and the tension roller 36 that contact the crawler 31 from the inside rotate (are driven) along with the rotation of the crawler 31. That is, the travel device 3 can independently drive the crawler 31 of the first travel body 301 and the second travel body 302 to rotate by driving the drive sprocket 33.

[0080] [4] Structure of the tension adjustment device

[0081] Next, refer to Figure 7 to Figure 17 The structure of the tension adjustment device 4 of the work vehicle 1 according to the present embodiment will be described in detail.

[0082] Hereinafter, the tension adjustment device 4 and the surroundings of the first traveling body 301 will be described using the drawings ( Figure 7 to Figure 17 ) The tension adjustment device 4 of the first traveling body 301 is described. As described above, the first traveling body 301 and the second traveling body 302 are symmetrical in the left-right direction D3, so the tension adjustment device 4 of the second traveling body 302 has the same structure as (symmetrical to) the tension adjustment device 4 of the first traveling body 301 and its description is omitted.

[0083] Figure 7 yes Figure 4 An enlarged view of the periphery of the tension adjustment device 4 of the first traveling body 301. Figure 8 It shows that Figure 7 FIG. 4 is a diagram showing a state where the carrier roller 34 and the guide frame 42 are removed. Fig. 9 Yes Figure 6 3 is an enlarged view of the tension adjustment device 4 and the surroundings of the first traveling body 301 in a state where the carrier roller 34 is removed, and shows a state where the upper layer has the guide frame 42 and a state where the lower layer has the guide frame 42 removed. Fig.10 Observed from above Fig. 9 It is a top view of the portion shown, and shows a state where the upper layer has the guide frame 42 and a state where the lower layer has the guide frame 42 removed.

[0084] Fig.11 It is shown along Fig.10 A three-dimensional view of the tension adjustment device 4 cut along the A1-A1 line. Fig.12 It is shown along Fig.10 1 is a left side view of the tension adjustment device 4 cut along the A1-A1 line, and shows a state in which the tension applied to the crawler belt 31 in the upper layer is small and a state in which the tension applied to the crawler belt 31 in the lower layer is large. Fig.13 It is shown along Fig. 9 A perspective view of the tension adjustment device 4 cut along the A2-A2 line. Fig.14 It is shown along Fig. 9 A top view of the tension adjustment device 4 cut along the A2-A2 line. Fig.15 It is shown along Fig. 9 The tension adjustment device 4 cut along the A2-A2 line, and the coupling member 46 described later (see Figure 7 ) is a top view of the cut state and a partial enlarged view (within the lead-out frame). Fig.16 It is shown along Fig.10 A perspective view of the tension adjustment device 4 cut along the A3-A3 line. Fig.17 It is shown along Fig.10 A rear view of the tension adjustment device 4 cut along the A3-A3 line, and a pressing member 412 described later is shown on the left side (see Figure 8 ) is shown in the figure before rotation, and the right side shows the state of the pressing member 412 after rotation.

[0085] Figures 11 to 17 In the drawings which show a partial section, hatching (oblique lines) of the section surface is omitted.

[0086] The guide frame 42 limits the displacement direction of the tension frame 43. In the present embodiment, the tension frame 43 can be displaced in the front-rear direction D2, so the guide frame 42 limits the movement of the tension frame 43 in directions other than the front-rear direction D2, thereby guiding the movement of the tension frame 43 in the front-rear direction D2. The guide frame 42 is directly or indirectly fixed to the track frame 32.

[0087] Specifically, the guide frame 42 is a frame member having a length in the front-to-back direction D2. The guide frame 42 has a hollow shape, and when the tension frame 43 is inserted therein, the displacement direction (movement direction) of the tension frame 43 is restricted. In the present embodiment, as an example, the guide frame 42 is formed in a shape in which the lower surface of the square tube is open, so that the cross section viewed from one direction in the front-to-back direction D2 is formed in a substantially C-shape with the lower surface open.

[0088] The tension frame 43 is combined with the guide frame 42 in such a manner that it can be displaced in the front-rear direction D2. Specifically, the tension frame 43 is a frame member having a length in the front-rear direction D2. The tension frame 43 is configured to be displaceable in the front-rear direction D2 in a manner that it can slide relative to the guide frame 42 inside the guide frame 42.

[0089] In this embodiment, as an example, the tension frame 43 has a pair of side plates 431 (see Figure 8 ) and top plate 432 (refer to Figure 8 ). A pair of side plates 431 are arranged to face each other in the left-right direction D3, and a top plate 432 is located above the pair of side plates 431 and connects the pair of side plates 431 to each other. In order to show the inner structure of the tension frame 43, Figure 8 The top plate 432 is represented by an imaginary line (two-dot chain line). Fig. 9 and Fig.10 The top plate 432 is omitted in the figure.

[0090] In addition, if Figure 7 to Figure 12 As shown, the tension adjustment device 4 includes a pressing device 41 , a supporting member 45 , a pair of coupling members 46 , and a fixing member 48 in addition to the guide frame 42 and the tension frame 43 .

[0091] like Figure 8 As shown, the pressing device 41 includes a main shaft component 411 and a pressing component 412. The main shaft component 411 has a length in a predetermined direction. The pressing device 41 uses the main shaft component 411 to press the pressing component 412 in one direction of the predetermined direction. In this embodiment, the predetermined direction as the length direction of the main shaft component 411 is the front-back direction D2, and the "one direction of the predetermined direction" in which the pressing component 412 is pressed by the main shaft component 411 is the "rear".

[0092] In this embodiment, as an example, the main shaft component 411 is a tension bolt having a length in the front-rear direction D2, and the pressing component 412 is a nut component screwed with the main shaft component 411. The pressing component 412 is stopped. The main shaft component 411 composed of the tension bolt rotates around its central axis, so that the pressing component 412 composed of the nut component moves parallel to the central axis direction (front-rear direction D2).

[0093] The pressing device 41 presses the tension frame 43 using the pressing member 412. That is, the pressing device 41 is configured to press the tension frame 43 backward by pressing the pressing member 412 against the tension frame 43 using the main shaft member 411. As a result, the tension roller 36 supported by the tension frame 43 is pressed against the crawler 31, so that tension can be applied to the crawler 31.

[0094] The support member 45 supports one end (in the length direction) of the main shaft member 411. In the present embodiment, the support member 45 supports the end of the main shaft member 411 on the opposite side of the pressing member 412. That is, the support member 45 supports the front end of the main shaft member 411 formed by the tension bolt. Here, the main shaft member 411 is supported by the support member 45 in a state where it can rotate only around the central axis, that is, in a state where parallel movement in the up-down direction D1, the front-back direction D2, and the left-right direction D3 is restricted.

[0095] Specifically, the support member 45 is a rectangular plate-shaped member having a length in the left-right direction D3. The support member 45 has a through hole 451 (see Fig.11 The front end of the main shaft member 411 penetrates the through hole 451 so that the relative movement of the main shaft member 411 in the vertical direction D1 and the horizontal direction D3 relative to the support member 45 is restricted. In addition, the main shaft member 411 has a flange portion 413 partially formed into a large diameter (see Fig.11 ), the flange portion 413 contacts the periphery of the through hole 451 of the support member 45 from the rear, thereby restricting the relative movement of the main shaft member 411 relative to the support member 45 in the forward direction.

[0096] The fixing member 48 is a member fixed to the crawler frame 32. When viewed from the support member 45, the fixing member 48 is located on the side of the pressing member 412, that is, the rear. In the present embodiment, the fixing member 48 is a rectangular plate-shaped member, and a pair of fixing members 48 is provided in a manner corresponding to the pair of coupling members 46. The pair of fixing members 48 is arranged to be separated in the left-right direction D3.

[0097] The pair of coupling members 46 is a member for coupling the support member 45 and the fixing member 48. The pair of coupling members 46 are arranged to be separated in the left-right direction D3. In the present embodiment, as an example, the pair of coupling members 46 each include a bolt 461 (see Fig.13 ) and nut 462 (refer to Fig.13 Each coupling member 46 is fastened to the support member 45 and the fixing member 48 by means of a bolt 461 and a nut 462 to couple the support member 45 and the fixing member 48 together.

[0098] Specifically, in a state where the front surface sides of the supporting member 45 and the pair of fixing members 48 overlap, a bolt 461 inserted from the rear is fastened to a nut 462 located in front of the supporting member 45, so that the pair of coupling members 46 fastens the supporting member 45 and the (pair of) fixing members 48. Here, the bolt 461 is inserted through the supporting hole 452 (see FIG. 4 ) formed in the supporting member 45. Fig.15 ), and the fixing hole 481 formed in the fixing member 48 (refer to Fig.15 ) and penetrate the supporting member 45 and the fixing member 48.

[0099] In this way, in a state where the support member 45 supporting one end of the main shaft member 411 is coupled to the fixing member 48 by the pair of coupling members 46, the one end of the main shaft member 411 is indirectly supported by the track frame 32 via the support member 45 and the fixing member 48. Therefore, in this state, at least the forward movement of the main shaft member 411 is restricted, and the pressing member 412 can be pressed relatively rearward with respect to the track frame 32.

[0100] On the other hand, when the pair of coupling members 46 is broken, the coupling between the support member 45 and the fixing member 48 is released, so that one end of the main shaft member 411 can move forward together with the support member 45. Therefore, in this state, since the main shaft member 411 can move forward, the pressing member 412 cannot be pressed rearward relative to the track frame 32.

[0101] However, regarding the travel device 3 involved in this embodiment, Figure 7 to Figure 12 As shown, at least a portion of the tension frame 43 is disposed in a recess 324 provided on one side surface of the track frame 32 along the front-rear direction D2.

[0102] That is, a recess 324 is formed on one side surface (upper surface, lower surface, right side surface or left side surface) of the track frame 32 along the displacement direction of the tension frame 43, that is, the front-rear direction D2. And, the tension frame 43 is combined with the track frame 32 in such a manner that at least a part of it is accommodated in the recess 324.

[0103] According to this structure, at least a part of the tension frame 43 is embedded in the track frame 32, so that the track frame 32 can easily receive the external force acting on the tension frame 43. As a result, there is an advantage that the strength of the support structure (tension frame 43, etc.) of the tension roller 36 can be easily improved.

[0104] Furthermore, since at least a portion of the tension frame 43 is buried in the crawler frame 32 , the tension adjustment device 4 can be easily configured compactly compared to a case where the tension frame 43 is disposed on the upper surface of the crawler frame 32 .

[0105] Specifically, the recessed portion 324 is provided on one side surface (along the front-rear direction D2 of the track frame 32), that is, the upper surface of the track frame 32. In other words, the side surface provided with the recessed portion 324 is the upper surface of the track frame 32. Thus, the tension frame 43 can be arranged above the track frame 32, and at least a part of the tension frame 43 can be arranged in the recessed portion 324 without significantly changing the layout of the tension frame 43 and the like.

[0106] In addition, the recessed portion 324 is open toward the upper side and the rear side. That is, the recessed portion 324 is provided at the rear end portion of the upper surface of the crawler frame 32, and is formed into a shape that is open not only toward the upper side but also toward the rear side. In the present embodiment, in particular, the recessed portion 324 is also open toward both sides in the left-right direction D3. According to this structure, it is easy to suppress the reduction in the strength of the crawler frame 32 due to the provision of the recessed portion 324.

[0107] More specifically, in the present embodiment, the crawler frame 32 is formed into a rectangular cylindrical shape having a length in the vertical direction D1 when viewed from one direction in the front-rear direction D2. A notch 325 (see FIG. 1 ) cut from the upper surface of the crawler frame 32 at a constant depth is provided at the rear end of the crawler frame 32. Fig.11 ), using the cover member 326 (refer to Fig.11 ) covers the cross section of the notch 325 to form the recess 324. Here, the cover member 326 is formed into a substantially L-shape when viewed from one direction of the left-right direction D3, and covers the entire cross section of the notch 325. That is, the upper surface of the cover member 326 constitutes the bottom surface of the recess 324.

[0108] In this embodiment, the tension frame 43 is disposed such that only the lower half thereof is accommodated in the recess 324. However, at least a portion of the tension frame 43 may be disposed in the recess 324, or the entire tension frame 43 may be disposed in the recess 324.

[0109] Here, in this embodiment, the pressing member 412 that presses the tension frame 43 in the direction that causes the tension roller 36 to leave the track frame 32 presses the acting portion between the center and the upper end of the tension frame 43 in the vertical direction D1. Figure 8 and Fig. 9 As shown, the main shaft member 411 that presses the pressing member 412 rearward is located above the track frame 32, so the pressing member 412 presses the tension frame 43 whose lower half is arranged in the recess 324 at a position (action site) above the center in the up-down direction D1.

[0110] According to this configuration, even when an excessive external force is applied to the tension roller 36, the moment acting on the tension frame 43 can be effectively received by the pressing member 412. Therefore, the strength of the tension frame 43 can be further improved.

[0111] In addition, the tension frame 43 is in contact with the bottom surface of the recessed portion 324. The bottom surface of the recessed portion 324 is formed by the upper surface of the cover member 326, and the tension frame 43 slides in the front-rear direction D2 relative to the cover member 326 while in contact with the upper surface of the cover member 326. Therefore, the tension frame 43 is supported by the bottom surface of the recessed portion 324 (the upper surface of the cover member 326), thereby improving the strength of the tension frame 43.

[0112] In addition, in the present embodiment, at least a portion of the guide frame 42 is disposed in the recessed portion 324. The guide frame 42 is disposed in the recessed portion 324 in the same manner as the tension frame 43. In this way, by embedding at least a portion of the guide frame 42 in the track frame 32, it is easy to configure the tension adjustment device 4 compactly, compared with the case where the guide frame 42 is disposed on the upper surface of the track frame 32. In addition, it is sufficient that at least a portion of the guide frame 42 is disposed in the recessed portion 324, and the entire guide frame 42 may be disposed in the recessed portion 324.

[0113] Here, the carrier roller 34 that contacts the crawler belt 31 from the inside is supported by the guide frame 42. Specifically, the rear carrier roller 34 is rotatably supported by the guide frame 42. Therefore, the protrusion amount of the carrier roller 34 from the crawler belt frame 32 can be suppressed to be small.

[0114] In addition, in the present embodiment, as described above, the track roller 35 located at the rearmost side is rotatably supported by the bracket 323 fixed to the track frame 32. The bracket 323 is provided so as to straddle the lower surface and the rear end surface of the track frame 32. That is, the bracket 323 is provided so as to straddle the one end (rear end) on the tension roller 36 side in the front-rear direction D2 of the track frame 32 and to support the track roller 35. The bracket 323 is provided so as to straddle the side surface (lower surface) and the end surface on the opposite side of the recessed portion 324 of the track frame 32.

[0115] According to this configuration, since track roller 35 can be supported by bracket 323 firmly fixed to track frame 32 , the support strength of track roller 35 is improved.

[0116] In addition, in the present embodiment, the (rear side) connecting member 303 is connected to the guide frame 42. In other words, the connecting member 303 connects the guide frame 42 to the machine 2. The guide frame 42 is fixed to the track frame 32, so the connecting member 303 is fixed to the track frame 32 via the guide frame 42. According to this structure, the connecting member 303 can be connected to the guide frame 42 without connecting to the track frame 32 which is thinner than other parts due to the provision of the recessed portion 324, and it is easy to ensure the connection strength between the connecting member 303 and the track frame 32.

[0117] However, if Figure 13 to Figure 15 As shown, the travel device 3 according to this embodiment includes a breaking mechanism 47 (see Fig.13 When one of the pair of coupling members 46 is broken, the breaking mechanism 47 causes a force for breaking the other coupling member 46 to act on the other coupling member 46 before a force for deforming the main shaft member 411 acts on the main shaft member 411 .

[0118] In the present embodiment, the support member 45 supporting one end of the main shaft member 411 is connected to the fixing member 48 by a pair of connecting members 46. Therefore, if both of the pair of connecting members 46 are broken, the connection between the support member 45 and the fixing member 48 is released. At this time, one end of the main shaft member 411 can move forward together with the support member 45, so the pressing member 412 cannot be pressed backward relative to the crawler frame 32. In other words, the pressing device 41 cannot press the tension frame 43 backward by the pressing member 412, so that the tension cannot be applied to the crawler 31 from the tension roller 36 of the tension adjustment device 4.

[0119] According to the above-mentioned breaking mechanism 47, when one of the pair of connecting components 46 is broken, the other connecting component 46 is broken before the force that deforms the main shaft component 411 acts on the main shaft component 411. Therefore, by bonding the other connecting component 46 without breaking, it is easy to avoid an unreasonable force acting on the main shaft component 411 and deforming the main shaft component 411. As a result, there is an advantage that the force that deforms the main shaft component 411 is difficult to be applied to the main shaft component 411. In addition, if the main shaft component 411 is not deformed, the main shaft component 411 can be reused, so the tension adjustment device 4 can be repaired by simply replacing the pair of connecting components 46.

[0120] Specifically, in this embodiment, the breaking mechanism 47 includes a support member 45 and a fixing member 48. That is, a through hole 451 is formed in the support member 45 for the main shaft member 411 to pass through, and a gap G1 is formed between the main shaft member 411 and the inner peripheral surface of the through hole 451 to prevent the main shaft member 411 from interfering with the inner peripheral surface of the through hole 451 when the support member 45 is tilted relative to the fixing member 48 (see Fig.14 ).

[0121] In short, the inner diameter of the through hole 451 is set to be slightly larger than the outer diameter of the spindle member 411, and a sufficient gap G1 is ensured between the inner peripheral surface of the through hole 451 and the outer peripheral surface of the spindle member 411. Fig.15 As shown, even if (the bolt 461 of) one (here, the left) coupling member 46 breaks and the support member 45 tilts, the gap G1 can be used to avoid interference (contact) between the main shaft member 411 and the inner peripheral surface of the through hole 451 .

[0122] That is, if one of the coupling members 46 is broken, the support member 45 may be tilted relative to the fixing member 48 by receiving the reaction force from the crawler 31 through the tension roller 36, the tension frame 43 and the pressing device 41. At this time, if the main shaft member 411 interferes with the inner peripheral surface of the through hole 451, the main shaft member 411 will be deformed. According to the breaking mechanism 47, such interference can be avoided and deformation of the main shaft member 411 can be avoided. Specifically, if the inclination of the support member 45 is less than a few degrees (for example, 9 degrees), the main shaft member 411 can be prevented from interfering with the inner peripheral surface of the through hole 451.

[0123] In addition, the breaking mechanism 47 sets the gap between the inner peripheral surface of the support hole 452 formed in the support member 45 and the connecting member 46 (the bolt 461) to be smaller than the gap G1 between the main shaft member 411 and the inner peripheral surface of the through hole 451, thereby achieving the breaking of the connecting member 46. That is, for example Fig.15 As shown, when the support member 45 is tilted relative to the fixing member 48, the central axes of the fixing hole 481 and the support hole 452 formed in the fixing member 48 are bent. At this time, a force to break the coupling member 46 (the bolt 461) that penetrates the fixing hole 481 and the support hole 452 is applied from the support member 45 and the fixing member 48.

[0124] Thus, in this embodiment, the breaking mechanism 47 causes at least one of bending stress and shearing stress to act on the other (i.e., the one that has not been broken first) connecting member 46 to break it. Specifically, the support member 45 is tilted, and the support member 45 and the fixing member 48 as the breaking mechanism 47 act on both bending stress and shearing stress on the connecting member 46 (the bolt 461) that penetrates the fixing hole 481 and the supporting hole 452. As a result, although a member with sufficient strength is used as the connecting member 46, when one connecting member 46 breaks, the other connecting member 46 is also likely to break actively.

[0125] In addition, the main shaft member 411 is located between the pair of coupling members 46 when viewed from above. In the present embodiment, the pair of coupling members 46 are arranged to be separated in the left-right direction D3, and the main shaft member 411 is located at the center of the pair of coupling members 46. Therefore, when one coupling member 46 is broken, the displacement amount of the support member 45 near the other coupling member 46 is larger than that of the main shaft member 411, so that the other coupling member 46 is easily broken actively.

[0126] Furthermore, in the present embodiment, the fixing member 48 is fixed to the guide frame 42. That is, the fixing member 48 is indirectly fixed to the track frame 32 by being fixed to the guide frame 42. Therefore, the fixing member 48 can be easily fixed to the track frame 32 firmly, and when one connecting member 46 is broken and the supporting member 45 is tilted, a force that breaks the other connecting member 46 can be easily generated.

[0127] However, if Fig.16 and Fig.17 As shown, a gap G2 is ensured between the pressing member 412 and the inner surface of the guide frame 42. The pressing member 412 is a part of the pressing device 41, and is a member that moves along the front-rear direction D2 inside the guide frame 42 to press the tension frame 43 in a direction that causes the tension roller 36 to leave the track frame 32.

[0128] Specifically, a stopper plate 44 is disposed below the pressing member 412 as a member for preventing the pressing member 412 from rotating. The stopper plate 44 is fixed to the tension frame 43. Here, the gap between the stopper plate 44 and the pressing member 412 is smaller than the gap G2 between the pressing member 412 and the inner surface of the guide frame 42.

[0129] Therefore, if Fig.17As shown in FIG. 1 , when the main shaft member 411 rotates, even if the pressing member 412 sometimes rotates together with the main shaft member 411, the pressing member 412 contacts the stopper plate 44 before the guide frame 42, thereby restricting further rotation. Therefore, the pressing member 412 can maintain a state of non-contact with the guide frame 42 (a state in which the gap G2 exists). As a result, the friction loss caused by the sliding of the pressing member 412 relative to the inner surface of the guide frame 42 can be suppressed.

[0130] [5] Modifications

[0131] The following lists modifications of Embodiment 1. The modifications described below can be combined as appropriate and applied.

[0132] The working vehicle 1 is not limited to a common combine harvester, and may be a self-shedding combine harvester, or a harvesting machine other than a combine harvester, or other working vehicles. The harvesting object of the working vehicle 1 is not limited to "rice" or grains. The driving unit 16 is not limited to a cab type, and may be, for example, a canopy type or a floor type.

[0133] In addition, the travel device 3 is not limited to a crawler type, and may be a half-crawler type, for example.

[0134] In addition, the work vehicle 1 may include a lifting device for raising and lowering the platform 2 relative to the travel device 3. In this case, the platform 2 is supported on the travel device 3 in a manner that can be raised and lowered by the lifting device. As a result, the height (vehicle height) of the platform 2 relative to the travel surface Fs1 is not fixed, but changes by driving the lifting device. Here, preferably, a pair of lifting devices are provided corresponding to the pair of crawlers 31, and the pair of lifting devices are driven independently. Thus, for example, when the travel surface Fs1 is tilted in a downward direction in one of the left and right directions D3, the platform 2 can be raised by the one lifting device to maintain the platform 2 in a horizontal state. In this way, the lifting device is not only used for vehicle height adjustment control to change the height (vehicle height) of the platform 2 relative to the travel surface Fs1, but also for automatic leveling control to correct the inclination of the flipping direction of the platform 2 and maintain the platform 2 in a horizontal state.

[0135] In addition, the specific shapes and sizes of the components of the tension adjustment device 4, such as the guide frame 42 and the tension frame 43, are not limited to the examples shown in Embodiment 1. For example, the recessed portion 324 for disposing at least a portion of the tension frame 43 is not limited to the upper surface of the track frame 32, and may be provided on the lower surface, the left side surface, or the right side surface, for example.

[0136] In addition, the tension adjustment device 4 of the travel device 3 only needs to include at least two (a pair) coupling members 46 , and may include three or more coupling members 46 .

[0137] In addition, regarding the structure of the breaking mechanism 47, the structure described in the first embodiment is only an example, and various structures can be adopted as long as the following structure is used: when one of the pair of connecting members 46 is broken, the force for breaking the other connecting member 46 acts on the other connecting member 46 before the force for deforming the main shaft member 411 acts on the main shaft member 411. For example, the breaking mechanism 47 can be a structure in which when the support member 45 is moved in the up-down direction D1 relative to the fixing member 48 like a pair of scissors, a shear stress acts on the connecting member 46 from the edge portions of both.

[0138] [Additional Notes on the Invention]

[0139] The following is a summary of the invention extracted from the above-mentioned embodiments. In addition, each structure and each processing function described in the following supplementary notes can be selected and combined arbitrarily.

[0140] <Note 1>

[0141] A travel device for a working vehicle, wherein:

[0142] The travel device of the working vehicle comprises:

[0143] The pressing device includes a main shaft member having a length in a predetermined direction, and uses the main shaft member to press the pressing member in one direction of the predetermined direction;

[0144] a supporting member for supporting one end portion of the main shaft member;

[0145] a pair of coupling members that couple the support member to the fixing member; and

[0146] A breaking mechanism causes a force for breaking the other connecting member to act on the other connecting member before a force for deforming the main shaft member acts on the main shaft member when one connecting member of the pair of connecting members is broken.

[0147] <Note 2>

[0148] The travel device of the working vehicle according to Supplementary Note 1, wherein:

[0149] The travel device of the working vehicle further comprises:

[0150] a crawler frame having a length in a front-rear direction;

[0151] a tension frame displaceable in a fore-and-aft direction relative to the track frame; and

[0152] a tension roller supported on the tension frame,

[0153] The pressing device presses the tension frame using the pressing member.

[0154] <Note 3>

[0155] The travel device of the working vehicle according to Supplement 2, wherein:

[0156] The travel device of the working vehicle further comprises: a guide frame for restricting the displacement direction of the tension frame;

[0157] The fixing component is fixed to the guide frame.

[0158] <Note 4>

[0159] The travel device of a working vehicle according to any one of Supplementary Notes 1 to 3, wherein:

[0160] The main shaft member is located between the pair of coupling members in a plan view.

[0161] <Note 5>

[0162] The travel device of a working vehicle according to any one of Supplementary Notes 1 to 4, wherein:

[0163] The breaking mechanism causes at least one of bending stress and shearing stress to act on the other connecting member.

[0164] <Note 6>

[0165] The travel device of a working vehicle according to any one of Supplementary Notes 1 to 5, wherein:

[0166] The support member has a through hole through which the main shaft member passes.

[0167] A gap is formed between the main shaft member and the inner peripheral surface of the through hole to prevent the main shaft member from interfering with the inner peripheral surface of the through hole when the support member is tilted relative to the fixing member.

[0168] <Note 7>

[0169] A working vehicle, wherein

[0170] The working vehicle has:

[0171] A travel device for a work vehicle according to any one of supplementary notes 1 to 6; and

[0172] The machine platform is supported by the travel device so as to be able to travel.

Claims

1. A travel device for a working vehicle, characterized in that: The travel device of the working vehicle comprises: The pressing device includes a main shaft member having a length in a predetermined direction, and uses the main shaft member to press the pressing member in one direction of the predetermined direction; a supporting member for supporting one end portion of the main shaft member; a pair of coupling members that couple the support member to the fixing member; and A breaking mechanism causes a force for breaking the other connecting member to act on the other connecting member before a force for deforming the main shaft member acts on the main shaft member when one connecting member of the pair of connecting members is broken.

2. The travel device of the working vehicle according to claim 1, characterized in that: The travel device of the working vehicle further comprises: a crawler frame having a length in a front-rear direction; a tension frame displaceable in a fore-and-aft direction relative to the track frame; and a tension roller supported on the tension frame, The pressing device presses the tension frame using the pressing member.

3. The travel device of the working vehicle according to claim 2, characterized in that: The travel device of the working vehicle further comprises: a guide frame for limiting the displacement direction of the tension frame, The fixing component is fixed to the guide frame.

4. The travel device of a working vehicle according to any one of claims 1 to 3, characterized in that: The main shaft member is located between the pair of coupling members in a plan view.

5. The travel device of a working vehicle according to any one of claims 1 to 3, characterized in that: The breaking mechanism causes at least one of a bending stress and a shearing stress to act on the other connecting member.

6. The travel device of a working vehicle according to any one of claims 1 to 3, characterized in that: The support member has a through hole through which the main shaft member passes. A gap is formed between the main shaft member and the inner peripheral surface of the through hole to prevent the main shaft member from interfering with the inner peripheral surface of the through hole when the support member is tilted relative to the fixing member.

7. A working vehicle, characterized in that: The working vehicle has: The travel device of the working vehicle according to any one of claims 1 to 3; and The machine platform is supported by the travel device so as to be travelable.

Images