JP2007116950A - Crawler type working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small crawler type tractor which utilizes the structure of a rear wheel-driving small wheel type tractor as much as possible to reduce the fuel cost. <P>SOLUTION: This crawler type working vehicle which has crawler type travel devices 80 under an upper vehicle body 90 is characterized by disposing side frames 82, 83 for connecting right and left crawler type travel devices 80 under the upper vehicle body 90 and fixing lower links 102L, 102R constituting a three point link type work apparatus to the side frame 83. The crawler type travel devices 80 each has a crawler frame 81 rotatably supporting driven idlers 85 at both the ends and a driving sprocket 60 mounted on the vehicle shaft (rear axle) 89, and has a crawler belt 95 wound between the driven idlers 85 and the driving sprocket 60. In addition, sway chains 104L, 104R are mounted between the lower links 102L, 102R and a side frame 83. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a crawler tractor, and more particularly, to a crawler tractor that can be easily manufactured using a common part with a wheel tractor.

  FIG. 8 is a perspective view of a conventional small wheel tractor (work vehicle). This tractor is a rear-wheel drive four-wheel vehicle, and such a wheel-type tractor includes a hydraulically driven tillage operation attachment, an attachment for paddy shaping, an attachment for soil disinfection, an attachment for creating a cultivation bed, an attachment for planting seeds In general, a work machine such as a multi-work attachment is attached. However, since the wheel-type tractor has a high ground pressure, the traveling performance on soft or rough terrain may not be sufficient, and particularly in the case of a small tractor, the traction force may not be sufficient due to its small size. In such a case, if the wheel type tractor can be improved to a crawler type tractor, the contact pressure can be reduced, so that it is possible to improve the running performance on soft or rough terrain, and at the same time increase the traction force.

  As such a technique, for example, there is one that improves a new crawler tractor by sharing a steering mechanism of a wheel tractor (Patent Document 1). In Patent Document 1, the difference between the crawler type and the wheel type turning mechanism, that is, when the wheel type tractor is modified to the crawler type, the brake device on one side is operated by depressing either the left or right brake pedal inside the turning. It was made in view of the fact that the turning operability was not good if the driving sprocket on one side was braked and the crawler inside the turning was decelerated to turn the vehicle body. The purpose of this invention is to make it possible to turn the vehicle body of the tractor and to reduce the cost by sharing parts using the steering mechanism provided in the wheel tractor.

  A wheeled work vehicle can run if the wheel is in contact with the ground even if the balance is somewhat poor, whereas a crawler type work vehicle may have insufficient traction because the front end of the crawler is lifted. Further, since the crawler tractor is mainly used for wet fields, it is necessary to set the ground clearance high. A technique for adjusting the tractor front-rear balance and ground clearance with a simple and inexpensive configuration has already been disclosed (Patent Document 2).

  Patent Document 2 discloses a tractor including a left and right crawler type traveling device in which a crawler is mounted between a driving sprocket and a driven idler, and a crawler frame that supports the driving sprocket and the driven idler is attached to a vehicle frame. On the other hand, a crawler type tractor is disclosed in which the attachment position can be adjusted in the front-rear direction and / or the vertical direction. The crawler type tractor disclosed in this Patent Publication 2 is presumed that the tractor portion is intended for a medium-sized or large-sized tractor, and the front end portion of the vehicle frame to which the crawler frame that supports the drive sprocket and the driven idler is attached, The crawler type traveling device is attached to the lower part of the tractor at the front part from the front part.

  On the other hand, a technique for simplifying the drive system of a small crawler tractor and improving turning performance has been developed particularly for medium and large tractors (Patent Document 3). For example, Patent Document 3 discloses a front wheel drive crawler tractor in which a hydraulic transmission turning mechanism (turning HST mechanism) for turning the airframe is connected to a drive system behind a forward / reverse switching mechanism for moving the airframe forward and backward. A small crawler tractor is disclosed in which the turning HST mechanism is divided into a variable displacement pump and a constant displacement motor, and the constant displacement motor is connected to the input shaft of the planetary gear type differential mechanism. This tractor is connected to the variable displacement pump by the output after the sub-shift of the traveling speed change mechanism, and makes the turning radius constant by making the vehicle speed and the rotation of the steering motor proportional to each other. The ring can be secured.

  In addition, the mission structure and axle case are integrated as a crawler-type tractor with improved work structure that is lightweight, simple, low-cost, and has a good balance between front and back and easy handling even when the overall length is short. There is also disclosed a front-wheel drive crawler tractor in which a transmission case is supported by a front and rear connecting frame that is horizontally configured between a pair of left and right crawler traveling devices, and an axle case is disposed in front of the connecting frame (patent) Reference 4).

JP 2000-159143 A JP 2002-145134 A JP 2004-17841 A JP 2004-66913 A

  The crawler tractor has a low contact pressure, so it is suitable for work in wet fields and can increase the traction force of the work equipment. However, as shown in Patent Document 1, the drive wheel of the wheel tractor is simply used as a drive sprocket. As a result, it may not be possible to secure a ground clearance suitable for work in wetlands. In particular, since the crawler tractor is required to adjust the left / right and up / down balance more strongly, it is convenient if such control can be adjusted more easily. In this case, as in Patent Document 2, a mounting hole is opened in the crawler frame, a mounting hole corresponding to the mounting hole is opened in the vehicle frame, and these are fixed by shifting in the front-rear and vertical directions. Then, there are many fixed parts, and operation is complicated. In addition, since the crawler tractor is heavier than the wheels, the left and right crawler traveling devices tend to be heavier in total weight, and the need for weight reduction is strongly desired.

  In addition, even in the case of a small crawler tractor, it is preferable to ensure an excellent operation feeling as in the case of a medium or large crawler tractor. However, steering hydraulic transmission mechanisms used to improve the feeling of turning, the reversing mechanism for moving the aircraft back and forth, the variable displacement pump of the turning hydraulic transmission mechanism, etc. are simply small crawler type It is structurally difficult to divert to a tractor. In particular, the crawler tractors described in Patent Document 3 and Patent Document 4 are front wheel drive systems in which a front axle case is provided separately from the transmission in the lower front part of the engine, and the structure of the rear wheel drive system is Different. Accordingly, it is not easy to manufacture a small rear wheel drive crawler tractor at a low cost by utilizing the basic structure of a small wheel drive tractor.

Accordingly, a first object of the present invention is to provide a small crawler tractor that can be manufactured by utilizing as much as possible the structure of a small wheel tractor driven by a rear wheel.
In addition, in conventional crawler type tractors, the lower case, sway chain, etc. are attached to the transmission case provided at the rear of the crawler frame, so it is necessary to apply a load to the transmission case and increase its strength. Therefore, there is a problem that the weight of the aircraft increases and fuel consumption and drivability deteriorate.
Accordingly, a second object of the present invention is to provide a compact crawler tractor with good fuel consumption.

  Therefore, the invention described in claim 1 has a crawler frame that rotatably supports the driven idler at both ends, and a drive sprocket mounted on the rear axle, and a crawler between the driven idler and the drive sprocket. In a crawler type work vehicle provided with a crawler type traveling device around which a belt is wound at a lower portion of an upper vehicle body, a side frame for connecting left and right crawler type traveling devices is disposed at a lower portion of the upper vehicle body, and a three-point link type A lower link constituting the work mounting device is fixed to the side frame.

  According to a second aspect of the present invention, in the crawler-type work vehicle according to the first aspect, a sway chain is mounted between the lower link and the side frame.

  According to the first aspect of the present invention, the crawler frame that rotatably supports the driven idler at both ends and the drive sprocket attached to the rear axle are provided, and the crawler belt is provided between the driven idler and the drive sprocket. In a crawler type work vehicle provided with a crawler type travel device to be wound on the lower part of the upper body, a side frame connecting the left and right crawler type travel devices is arranged at the lower part of the upper car body, and a three-point link type work attachment device Since the lower link which comprises is fixed to a side frame, an agricultural machine can be attached, without applying a load to a mission case. Therefore, a small crawler tractor with good fuel consumption can be provided.

  According to the second aspect of the present invention, since the sway chain is mounted between the lower link and the side frame, the agricultural machine can be mounted without applying a load to the transmission case. Therefore, a small crawler tractor with good fuel consumption can be provided.

  In addition, according to the present invention, since the common part provided in the small wheel tractor is used, a small crawler tractor can be manufactured at low cost. In addition, it is possible to provide a small crawler-type tractor that has a larger force for towing a farm work machine than a wheel-type tractor and is excellent in running performance on soft or rough terrain.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.
1 is a side view of a small crawler tractor according to an embodiment of the present invention, FIG. 2 is a perspective view of a crawler traveling device in the tractor, FIG. 3 is a sectional plan view of the tractor, and FIG. 4 is a drive unit in the tractor. FIG. 5 is an enlarged sectional plan view of the vicinity of the operating mechanism in the transmission case.

  First, a schematic configuration of the crawler tractor 1 will be described. As shown in FIG. 1, a bonnet 2 that covers an engine 3 (not shown) is disposed in front of the vehicle 1, and a cabin 4 for operating the vehicle 1 or a not-shown lops frame is disposed behind the bonnet 2. . A steering handle 9 that controls the operation of the vehicle 1 is arranged in front of the cabin 4, and a driver's seat 8 is operated in the rear, and on the left and right of the driver's seat 8, the vehicle 1 is operated and the working machine 6 is raised and lowered. Various levers (not shown) such as a main transmission lever, a sub transmission lever, and a PTO operation lever are provided. In the unlikely event that the vehicle 1 rolls over, the cabin 4 including four safety frames for protecting the driver is formed so as to cover the entire driver seat 8. A step 10 for raising and lowering the driver's seat 8 is provided below the cabin 4. A work machine 6 that can be removed according to work is attached to the rear of the upper vehicle body 90, and the work machine 6 performs work such as plowing and rotary. Further, a pair of left and right crawler type traveling devices 80 for traveling the vehicle 1 are disposed below the upper vehicle body 90.

  As shown in FIG. 2, the crawler type traveling device 80 includes two left and right crawler frames 81L and 81R extending in the traveling direction, and two side frames 82 and 83 connecting the crawler frames 81L and 81R. The driven idlers 85 are rotatably supported at the front and rear ends of the crawler frames 81L and 81R, respectively. Between the two driven idlers 85, four equalizer wheels 86 are rotatably supported. . The two driven idlers 85, the four equalizer wheels 86, and the drive sprocket 60 pivotally supported by the rear axle case 88 have a straight line connecting the two driven idlers 85 with the drive sprocket 60 at the top. The crawler type traveling device 80 is formed by winding the crawler belt 95 in a substantially triangular shape. The total length of the crawler type traveling device 80 is 50 to 55% of the length of the upper vehicle body 90.

  Two support members 87 are further provided upward from the front side frame 82, and the upper vehicle body 90 is secured by bolting the support members 87 to the side surfaces of the clutch housing 5 described later. And the crawler type traveling device 80 are connected. In addition, left and right rear axle cases 88L and 88R for supporting left and right axles (rear axles) 89L and 89R to which the left and right drive sprockets 60L and 60R are connected are provided at the rear portions of the crawler frames 81L and 81R. The left and right rear axle case stays 99L and 99R are integrally formed on the upper side.

  Hereinafter, the traveling system of the crawler tractor 1 of the present invention will be described. As shown in FIG. 3, the power from the engine 3 is shifted by the main / sub transmission 39 in the transmission case 23 via the clutch housing 5 and then input to the left and right differential mechanisms 50L and 50R. Then, the crawler type traveling device 80 is driven by the left and right drive sprockets 60L and 60R via the left and right axles 89L and 89R extended from the differential mechanisms 50L and 50R. Further, a turning hydraulic transmission mechanism (HST) pump 72 for turning the vehicle 1 described later is provided on the side of the mission case 23, and a turning HST motor 73 is provided above the differential mechanism 50L. Further, the differential mechanisms 50L and 50R can be interchanged left and right.

  A movable swash plate (not shown) in the turning HST pump 72 that is a variable displacement type is linked to the steering handle 9 via a sub-transmission arm (not shown), and the turning HST pump 72 according to the steering amount of the steering handle 9. Is adjusted, and the output rotation speed and rotation direction of the turning HST motor 73 are controlled in accordance with the discharge amount. Then, the output of the turning HST motor 73 and the output from the auxiliary transmission 39 are combined in a differential mechanism 50 described later, and the drive sprockets 60L and 60R are driven to rotate via the axles 89L and 89R.

  In the crawler tractor 1 according to the present invention, the turning HST pump 72 and the turning HST motor 73 are provided as described above. However, the turning HST pump 72 that is usually disposed in the lower portion of the transmission case 23 is used in the present invention. Can be secured in parallel with the mission case 23 to ensure a high minimum ground clearance. Further, since the turning HST pump 72 and the turning HST motor 73 are separate bodies, the turning HST motor 73 can be repaired by arranging the turning HST motor 73 above the mission case 23. The oil stored in the mission case 23 does not flow out of the turning HST motor 73, so that the turning HST motor 73 can be easily removed and maintained, and the working efficiency is improved. Further, by disposing the turning HST motor 73 on the upper part of the transmission case 23, particularly on the differential mechanism 50 described later, oil leaked from the turning HST motor 73 can be directly flowed down to the differential mechanism 50. it can.

  Next, the configuration of power transmission in the mission case 23 will be described. As shown in FIG. 4, the output shaft 31 of the engine 3 is input to the forward / reverse switching mechanism 7 via the clutch housing 5. In the forward / reverse switching mechanism 7, when the vehicle 1 moves forward, the output shaft 31 and the forward gear 32 mesh with each other. On the other hand, when the vehicle 1 moves backward, the output shaft 31 and the reverse gear 34 counter the counter counter 35 for reverse movement. By engaging through the gear 36, the vehicle 1 moves forward and backward.

  Then, power is transmitted from the forward / reverse switching mechanism 7 to the main auxiliary transmission 39 at the rear of the vehicle 1 through the main shaft 37. The main shaft 37 and the main transmission shaft 41 positioned above the main shaft 37 are connected via four main transmission gears 42 having different numbers of teeth (in the case of four main transmission gears). The main transmission gear 42 always meshes with the gear 66 on the main shaft 37 and rotates together. On the other hand, the main transmission gear 42 is loosely fitted on the main transmission shaft 41, and the main transmission shaft 41 is not rotated by the rotation of the main transmission gear 42. By selectively fixing any of the gears 42 on the main transmission shaft 41, the main transmission shaft 41 is driven to rotate according to the number of teeth of the main transmission gear 42 fixed on the main transmission shaft 41. .

  The main transmission shaft 41 that is rotationally driven in this way is located behind the main transmission shaft 41 and is connected to the auxiliary transmission shaft 45 from the two gears 62 fixed on the main transmission shaft 41 via the auxiliary transmission gear 46. Is transmitted to. On the auxiliary transmission shaft 45, two auxiliary transmission gears 46 having different numbers of teeth (in the case of two auxiliary transmission stages) are slidably formed. The auxiliary transmission lever (not shown) causes these two gears 46 to be slidable. The power after the sub-shift is obtained by sliding back and forth on the sub-transmission shaft 45 and selectively meshing with any of the gears 62 on the main transmission shaft 41. The power after the sub-shift is changed from the front-rear direction to the left-right direction via a bevel gear 47 located at the rear end of the sub-transmission shaft 45, and differential mechanisms 50L and 50R located behind the mission case 23 described later. Will be entered.

  A part of the output of the engine 3 is connected to the PTO countershaft 49 via the PTO transmission gear 48 from the forward / reverse switching mechanism 7 and transmitted to the PTO output shaft 91 at the rear of the vehicle 1. The power for driving the turning HST pump 72 is transmitted to the plurality of counter shafts 61 through the counter gear 64 fixed on the sub transmission shaft 45, and finally. It is transmitted to the input shaft 63 of the turning HST pump 72 by driving the belt. In particular, the power for driving the turning HST pump 72 is input from the counter shaft 61 to the turning HST pump 72 via the chain 65 or the like, so that the turning HST pump 72 can be arranged at an arbitrary position. It becomes possible. Therefore, the minimum ground clearance of the vehicle 1 can be increased by disposing the turning HST pump 72 that is conventionally disposed at the lower part of the transmission case 23 on the side surface of the transmission case 23.

  Next, the configuration of the differential mechanism 50 for turning the vehicle 1 will be described. As shown in FIG. 5, the power after the sub-shift in the front-rear direction is transmitted via the bevel gear 47 fixed to the rear end of the sub-transmission shaft 45 and the bevel gear 21 fixed to the center portion of the pinion shaft 22. Then, the rotation direction is changed to the left and right direction, and transmitted to the left and right differential mechanisms 50L and 50R described later. Gears 25L and 25R fixed to both left and right ends of the pinion shaft 22 drive the left and right input shafts 20L and 20R via gears 27L and 27R meshing with the gears 25L and 25R. The input shafts 20L and 20R rotationally drive sun gears 51L and 51R of the planetary gear mechanism 50 that is the differential mechanism 50. The planetary gear mechanism 50 outputs a differential rotation for turning.

  Further, the planetary gear mechanism 50 will be described in detail. The planetary gear mechanisms 50L, 50R include sun gears 51L, 51R fixed to the input shafts 20L, 20R, planetary gears 53L, 53R provided around the sun gears 51L, 51R so as to freely revolve, and the planetary gears 53L, It includes carriers 55L and 55R that rotatably support 53R and are freely loosely fitted to the input shafts 20L and 20R and the axles 89L and 89R. Further, carrier gears 56L and 56R are formed on the outer circumferences of the carriers 55L and 55R.

  Due to the configuration of the planetary gear mechanisms 50L and 50R, when the vehicle 1 goes straight, that is, when the rotations of the left and right drive sprockets 60L and 60R are equal to each other, the carriers 55L and 55R do not rotate and the planetary gear mechanism 50L. , 50R rotates on the respective shafts on the spot to rotate the drive sprockets 60L, 60R. As a result, the left and right drive sprockets 60L and 60R rotate in the same rotational speed and in the same rotational direction, respectively, and move the vehicle 1 straight. On the other hand, when the vehicle 1 turns, that is, when the left and right drive sprockets 60L and 60R have different rotation speeds, the carriers 55L and 55R are driven to rotate by a turning HST motor 73, which will be described later. The planetary gears 53L and 53R of 50L and 50R are revolved around the sun gears 51L and 51R.

  Then, in addition to the rotation of the sun gears 51L and 51R, the planetary gears 53L and 53R located between the sun gears 51L and 51R and the carriers 55L and 55R start to revolve around the sun gears 51L and 51R by the rotation of the carriers 55L and 55R. . At this time, when the rotation of the sun gears 51L and 51R and the rotation of the carriers 55L and 55R are in the same direction, the rotation sum of the rotation of the sun gears 51L and 51R and the rotation of the carriers 55L and 55R is the planetary gear 53L. The axle gears 58L and 58R are rotated through the self-revolution of 53R.

  On the other hand, when the rotation of the sun gears 51L and 51R and the rotation of the carriers 55L and 55R are different directions, the rotation difference between the rotation of the sun gears 51L and 51R and the rotation of the carriers 55L and 55R is the planetary gear 53L, The axle gears 58L and 58R are rotated through the self-revolution of 53R.

  Here, the rotation of the carriers 55L and 55R is rotationally driven by the turning HST motor 73. The turning HST motor 73 is rotationally driven as the steering handle 9 is steered as described above, and the turning HST motor 73 is driven. The rotation of the left and right reversing shafts 43L and 43R is reversely rotated via the left and right reversing gears 52L and 52R engaged with the output gear 35 of the turning HST motor 73, respectively. The reversing shafts 43L and 43R respectively rotate the left and right carriers 55L and 55R through differential gears 44L and 44R fixed to one end of the reversing shafts 43L and 43R and carrier gears 56L and 56R, respectively. . In this way, as the turning HST motor 73 rotates, the left and right carriers 55L and 55R of the planetary gear mechanism 50 rotate in the reverse direction. As a result, one planetary gear mechanism 50 is rotated and the other planetary gear mechanism 50 is rotated. Since the gear mechanism 50 is subtracted from the rotation, the left and right drive sprockets 60L and 60R rotate at different rotational speeds to turn the vehicle 1.

  In this way, the HST motor for turning which is driven to rotate by the output of the straight traveling transmitted from the front engine 3 to the rear portion via the main auxiliary transmission 39 in the transmission case 23 and the steering handle 9 is steered. 73 is combined in the differential mechanism (left and right planetary gear mechanisms 50L and 50R) 50, so that the drive sprockets 60L and 60R of the left and right crawler travel devices 80 are differentially rotated to the left or right. In this configuration, the vehicle 1 is turned to the right.

  Further, a plurality of brake plates 29 are formed on one end of the pinion shaft 22 on the pinion shaft 22, and when a brake pedal (not shown) is operated by a driver's operation, the brake arm 28 rotates in conjunction with it. As the brake arm 28 rotates, a brake action is generated on the pinion shaft 22 and the vehicle 1 is decelerated.

  In particular, the brake plate 29 is located at the right end of the pinion shaft 22, and a brake case (not shown) that houses a brake plate, a brake arm, and the like is integrated with a right rear axle case 80R that houses the right planetary gear mechanism 50R. Is possible. Further, since the turning HST motor 73 is located on the left rear axle case 88L, the brake mechanism arranged in the right rear axle case 88R, and the turning HST motor 73 arranged in the left rear axle case 88L Thus, the weight balance of the vehicle 1 can be maintained.

  Furthermore, by arranging the brake mechanism and the turning HST motor 73 separately on the left and right, a link relationship (not shown) constituting the brake mechanism and hydraulic piping (not shown) constituting the turning HST mechanism are provided. The left and right rear axle cases 88L and 88R can be separately arranged, and there is an effect that the maintainability of the vehicle 1 is improved.

  Next, a specific configuration of the attachment position of the three-point link type attachment device for attaching various work machines to the rear end portion of the vehicle 1 will be described. FIG. 6 is a plan view mainly showing the rear part of the tractor, and FIG. 7 is a side view in the vicinity of the rear part of FIG.

  The rear end of the transmission case 23 is fixed at the center of the front part on the side frame 83 at the rear part of the vehicle 1 connecting the left and right crawler frames 81L and 81R. The fulcrum 100a of the top link 100 is attached to the upper center of the mission case 23, and the left and right fulcrums 101aL and 101aR of the left and right lift arms 101L and 101R including hydraulic lifting cylinders (not shown) are attached to both upper ends of the mission case 23. .

  A substantially U-shaped left and right lower link stay 102aL, 102aR is attached to the center of the side frame 83 so as to sandwich the mission case 23, and the left and right fulcrum of the left and right lower links 102L, 102R are attached to the left and right lower link stays 102aL, 102aR. The shafts 102bL and 102bR are supported by the pins 102cL and 102cR. Further, the front portions of the left and right lower links 102L and 102R and the rear ends of the left and right lift arms 101L and 101R are connected by left and right lift rods 103L and 103R.

  On the side frames 83 further outside the left and right lower link stays 102aL and 102aR, fulcrums 104aL and 104aR of the left and right sway chains 104L and 104R are attached. The rear ends of the left and right sway chains 104L and 104R are attached to the central portions of the left and right lower links 102L and 102R.

  A rear working machine such as a tillage rotary working machine or plow (not shown) is detachably attached to the tips of the top link 100 and the left and right lower links 102L and 102R, and the right lower is provided via the top link 100 and the left and right lift rods 103L and 103R. Work on the field is performed by raising and lowering the post-work machine with links 102L, 102R and the like. Further, since the left and right lower links 102L and 102R are supported by the left and right sway chains 104L and 104R, it is possible to prevent the left and right lower links 102L and 102R from shaking in the left and right directions during traveling and work.

  Thus, the left and right lower link stays 102aL and 102aR and the fulcrums 104aL and 104aR of the left and right sway chains 104L and 104R are provided on the side frame 83, and the left and right lower links 102L and 102R and the left and right sway chains 104L and 104R are respectively attached. Since the load on the transmission case 23 to which they are conventionally attached is eliminated, it is not necessary to reinforce the material of the transmission case 23, and therefore the increase in the weight of the vehicle 1 can be suppressed.

  As described above in detail, the crawler tractor 1 of this example has a crawler frame 81 that rotatably supports a driven idler 85 at both ends, and a drive sprocket 60 mounted on an axle (rear axle) 89, and A crawler type traveling device 80 in which a crawler belt 95 is wound between the driven idler 85 and the drive sprocket 60 is provided at the lower part of the upper vehicle body 90, and the side connecting the left and right crawler type traveling devices 80 to the lower part of the upper vehicle body 90. Frames 82 and 83 are provided, and lower links 102L and 102R constituting the three-point link type work mounting device are fixed to the side frames 83. In addition, the sway chains 104L and 104R are further mounted between the lower links 102L and 102R and the side frame 83.

  In the above-described example, a small crawler tractor (agricultural work machine) has been described as an example of a work machine. However, the present invention is not limited to this, and a combiner or the like as a farm work machine or a backhoe as a construction work machine. Therefore, it can be applied to all small work machines equipped with crawlers such as bulltoza.

It is a side view showing a small crawler type tractor as an example of the present invention. It is a perspective view of the crawler type traveling device vicinity in the tractor shown in FIG. It is a cross-sectional top view of the tractor shown in FIG. It is a cross-sectional side view of the drive part in the tractor shown in FIG. FIG. 2 is an enlarged plan view of the vicinity of a differential mechanism in a mission case in the tractor shown in FIG. 1. FIG. 2 is a plan view mainly showing a rear portion of the tractor shown in FIG. 1. FIG. 7 is a side view of the vicinity of the rear portion of the tractor shown in FIG. 6. It is a perspective view which shows the conventional small wheel type tractor.

Explanation of symbols

23 mission case 83 side frame 100 top link 100a, 101aL, 101aR, 104aL, 104aR fulcrum 101L, 101R lift arm 102L, 102R lower link 102aL, 102aR lower link stay 102bL, 102bR fulcrum shaft 102cL, 102cR pin 103L, 103R lift rod 104 104R sway chain

Claims (2)

A crawler type traveling device having a crawler frame that rotatably supports a driven idler at both ends and a drive sprocket attached to a rear axle, and a crawler belt wound around the driven idler and the drive sprocket. In the crawler type work vehicle provided at the bottom of the upper body,
The crawler type is characterized in that a side frame for connecting left and right crawler type traveling devices is disposed below the upper vehicle body, and a lower link constituting a three-point link type work mounting device is fixed to the side frame. Work vehicle.   The crawler work vehicle according to claim 1, further comprising a sway chain mounted between the lower link and the side frame.

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