JP2008049867A - Crawler type working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small crawler type tractor which can be manufactured by utilizing a structure of a rear wheel-driven small wheel type tractor to the maximum extent possible, and enhance the productivity, fuel consumption, and durability of a bearing. <P>SOLUTION: A crawler type traveling device having crawler frames for rotatably supporting a driven idler on both ends and a drive sprocket 60 fitted to an axle 89 while a crawler belt 95 being wrapped around between the driven idler and the drive sprocket 60 is provided on a lower part of a vehicle body. The driving force of a sub speed change shaft 45 by the power of an engine is transmitted to the drive sprocket 60 via a gear 47 provided on a rear end of the sub speed change shaft 45 and a gear 21 provided on a pinion shaft 22, and via a differential mechanism 50 from the pinion shaft 22. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a crawler type traveling having a crawler frame that rotatably supports a driven idler at both ends, and a drive sprocket mounted on an axle, and a crawler belt wound between the driven idler and the drive sprocket. The device is installed in the lower part of the fuselage, and the driving force of the auxiliary transmission shaft by the power of the engine passes through the gear provided at the rear end of the auxiliary transmission shaft and the gear provided on the pinion shaft, and from the pinion shaft through the differential mechanism. More specifically, a crawler work vehicle that transmits to a drive sprocket is linked to a bearing provided on the pinion shaft in the vicinity of both ends of the pinion shaft, and further provided with a bearing on the inner side of each of the bearings. The present invention relates to linking a gear provided on a pinion shaft between bearings provided inside.

  FIG. 7 is a perspective view of a conventional small wheel tractor (work vehicle). This tractor is a rear-wheel drive four-wheeled vehicle. Generally, such a wheel-type tractor is a hydraulically driven tillage operation attachment, an attachment for paddy shaping, an attachment for soil disinfection, an attachment for creating a cultivation floor, and a seed planting It is common that work machines such as a work attachment and a multi-work attachment are 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). This Patent Document 1 describes 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. An object of the present invention is to make it possible to turn the body of a crawler tractor and to reduce the cost by sharing components using a steering mechanism provided in the wheel tractor.

  In addition, 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 2). For example, Patent Document 2 discloses a front-wheel drive crawler tractor in which a hydraulic shift 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 back and forth. 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.

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

  However, when manufacturing a small crawler tractor using the basic structure of a small wheel tractor, simply using the wheel-type tractor drive wheel as a drive sprocket, There are cases where it cannot be secured. In addition, the hydraulic continuously variable transmission mechanism for steering that turns the aircraft, the reverser mechanism that moves the aircraft forward and backward, and the variable displacement pump of the turning hydraulic transmission mechanism that are used to improve the turning feeling are simply compact. It is structurally difficult to divert to this crawler type tractor. In particular, the crawler tractor described in Patent Document 3 is a front wheel drive system in which a front axle case is provided separately from the transmission in the lower front part of the engine and is different in structure from the rear wheel drive system. Therefore, it is not easy to manufacture a small rear wheel drive crawler tractor at low cost by using the basic structure of a small rear wheel drive wheel tractor.

  Next, in such a conventional crawler type tractor, the driving force of the auxiliary transmission shaft by the power of the engine is such that the gear provided at the rear end of the auxiliary transmission shaft, the gear provided on the pinion shaft, and the Since the pinion shaft is supported by the bearing when it is transmitted from the pinion shaft to the drive sprocket via the differential mechanism via the bearing linked to the gear, the pinion shaft is loaded with a driving force from the auxiliary transmission shaft. Is directly received by the bearing linked to the gear on the pinion shaft, for example, in the same small tractor with increased horsepower, the weight increases with the diameter, and it cannot withstand the load of the auxiliary transmission shaft with a large driving force, This causes a problem that the pinion shaft is bent. Therefore, if the diameter of the pinion shaft is increased in order to increase the strength, the weight of the fuselage increases, and there is a problem that productivity and fuel consumption are reduced. Furthermore, since the left and right bearings provided near both ends of the pinion shaft support the load of the pinion shaft accompanied by the load of the auxiliary transmission shaft and the load of the axle, the bearing is damaged early. There was also a problem.

  Therefore, an object of the present invention is to produce a small crawler tractor by utilizing the structure of a small wheel tractor driven by a rear wheel as much as possible, and further improve productivity, fuel consumption, and durability of a bearing. A tractor is provided.

  Therefore, the invention described in claim 1 includes a crawler frame that rotatably supports a driven idler at both ends, and a drive sprocket mounted on an axle, and a crawler between the driven idler and the drive sprocket. A crawler type traveling device around which a belt is wound is provided at the lower part of the fuselage, and a driving force of an auxiliary transmission shaft by engine power is provided at a rear end of the auxiliary transmission shaft, and a gear provided on a pinion shaft. A crawler-type work vehicle that transmits from the pinion shaft to the drive sprocket via a differential mechanism, the gears provided on the pinion shaft are linked to bearings provided near both ends of the pinion shaft, and each of the bearings A bearing is further provided inside the machine body, and a gear provided on the pinion shaft is linked between the bearings provided inside the machine body.

  According to a second aspect of the present invention, in the crawler work vehicle according to the first aspect, the pinion shaft is divided and arranged on the left and right sides from the vicinity of the center.

  According to a third aspect of the present invention, in the crawler type work vehicle according to the first aspect, a torque transmission surface of the pinion shaft to which a driving force from the auxiliary transmission shaft is transmitted is arbitrarily set within a cylindrical tooth width of the gear. It is possible to do.

  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 mounted on the axle are provided, and the crawler belt is provided between the driven idler and the drive sprocket. A crawler type traveling device to be wound is provided at the lower part of the fuselage, and the driving force of the auxiliary transmission shaft by the power of the engine is via a gear provided at the rear end of the auxiliary transmission shaft and a gear provided on the pinion shaft. In a crawler type work vehicle that transmits from a shaft to a drive sprocket via a differential mechanism, gears provided on the pinion shaft are linked to bearings provided near both ends of the pinion shaft, and further bearings are provided on the inner sides of the respective bodies of the bearings. Since the gear provided on the pinion shaft is linked between the bearings provided on the inner side of the fuselage, the pinion shaft is bent from the auxiliary transmission shaft to the rear of the fuselage by the bearing close to the gear. That the load support can support the load to rotate the pinion shaft from the sub transmission shaft by far bearings gear. Therefore, only the rotational torque for transmitting the driving force to the axle is applied to the pinion shaft, and the pinion shaft can be prevented from bending even if the diameter and weight of the auxiliary transmission shaft are increased in order to increase the horsepower of the fuselage. Since it is not necessary to increase the diameter of the shaft, an increase in the weight of the airframe can be prevented. Therefore, it is possible to provide a crawler tractor with improved productivity and fuel consumption.

  According to the invention described in claim 2, since the pinion shaft is divided and arranged on the left and right sides from the vicinity of the center, the weight of the body can be reduced by reducing the weight of the pinion shaft. Further, since the pinion shaft is divided, the gear can be easily attached and detached as compared with the conventional case where the pinion shaft penetrates the gear. Therefore, a crawler tractor with improved safety, workability, and fuel efficiency can be provided.

  According to the third aspect of the present invention, the torque transmission surface of the pinion shaft to which the driving force from the auxiliary transmission shaft is transmitted can be arbitrarily set within the cylindrical tooth width of the gear, so that the diameter of the auxiliary transmission shaft is increased. Thus, even if the driving force transmitted from the auxiliary transmission shaft to the pinion shaft is increased, if the pinion shaft is lengthened, the transmission surface meshing with the gear becomes wider, and the torque applied to the pinion shaft can be kept constant. Therefore, regardless of the power of the tractor, gears and bearing parts can be used widely, and a crawler tractor with improved productivity can be provided.

  In addition, according to the present invention, a small crawler tractor can be manufactured at low cost by using a common part provided in a small wheel tractor. 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 type tractor according to an embodiment of the present invention, FIG. 2 is a perspective view of a crawler type traveling device in the tractor, FIG. 3 is a sectional plan view of the tractor, and FIG. 4 is a drive in the tractor. FIG. 5 is an enlarged sectional plan view of the vicinity of the differential mechanism in the transmission case.

  First, a schematic configuration of the crawler tractor 1 will be described. A bonnet 2 that covers the engine 3 and the fuel tank 7 in front of the vehicle 1 and is loaded on the vehicle body frame 11, and a cabin 4 for operating the vehicle 1 or a Lopps frame (not shown) behind the bonnet 2. Arranged. 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 cabin 4 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.

  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 rotationally driven 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 vicinity of the mission case 23 will be described. As shown in FIG. 4, the power of the engine 3 is transmitted to the main shaft 37 via the output shaft 31. Transmission gears 37a, 37b, 37c, and 37d fixed to the main shaft 37 are a main transmission first speed gear 41a, a main transmission second speed gear 41b, a main transmission third speed gear 41c, and a main transmission that are loosely fitted to the main transmission shaft 41. The four-speed gear 41d is meshed with each other. The two main transmission clutch sliders 41e and 41f, which are spline-fitted so as to be slidable in the axial direction of the main transmission shaft 41, are linked to a main transmission lever (not shown) provided in the upper part 4 of the machine body. Claws formed on the main transmission clutch sliders 41e and 41f, the main transmission first speed gear 41a, the main transmission second speed gear 41b, the main transmission third speed gear 41c, and the main transmission fourth speed gear 41d by the operation of the main transmission lever, And the power is transmitted from the main shaft 37 to the main transmission shaft 41 via any one of the selected main transmission gears 41a, 41b, 41c, 41d.

  In addition, a forward / reverse switching mechanism 7 in which the forward rotation side gear 7a and the reverse rotation side gear 7b are loosely fitted on the same shaft center is provided at a forward extension portion of the main transmission shaft 41 in the vehicle traveling direction. Then, a reverser clutch 7c is selectively connected to either the forward side or the reverse side by operating a reverser lever (not shown) provided in the upper part 4 of the machine body, and the rotation of the main transmission shaft 41 is rotated on the forward side gear 7a or the reverse side. It is transmitted to one of the gears 7b. However, when the reverser lever is in the neutral position, the rotation is not transmitted to either the forward rotation side gear 7a or the reverse rotation side gear 7b.

  The forward rotation side gear 7a is meshed with a gear 42a fitted to the transmission shaft 42, and the reverse rotation side gear 7b is meshed with a counter gear 32a fitted to the counter shaft 32. The counter gear 32a is engaged with the transmission shaft 42. And meshed with a gear 42b fitted to the gear. As a result, when the reverser clutch 7c is connected to the forward side, the rotational power of the main transmission shaft 41 is transmitted to the transmission shaft 42 via the forward rotation side gear 7a, and the reverser clutch 7c is connected to the reverse side. The rotational power of the main transmission shaft 41 enables the transmission shaft 42 to rotate in the reverse rotation direction from the reverse rotation side gear 7b via the counter shaft 32.

  The gear 42a fitted to the transmission shaft 42 meshes with the forward rotation side gear 7a and meshes with the gear 34 provided on the coaxial line of the auxiliary transmission shaft 45 and provided in the vehicle traveling direction front. An auxiliary transmission shifter 45 a is spline-fitted to the auxiliary transmission shaft 45 so that it can freely slide between the front portion of the auxiliary transmission shaft 45 and the rear portion of the gear 34.

  The auxiliary transmission shifter 45a is operated by an auxiliary transmission lever (not shown) in the upper part 4 of the fuselage, and the auxiliary transmission shifter teeth 45b formed at the front of the auxiliary transmission shifter 45a are located at the rear position 34a of the gear 34. Sub-transmission third gear, sub-transmission shifter teeth 45b and teeth 34b provided at the rear end of the gear 34 mesh with the second sub-transmission second gear, teeth 45c formed at the upper center of the sub-transmission shifter 45a and the transmission shaft 42. A sub-transmission device is configured that can be switched to a sub-speed first speed in a state in which a gear 42c provided near the center of the gear meshes with the gear 42c, a neutral state in which rotational power is not transmitted to the sub-shift shifter 45a, and the like. By selecting the gear meshing by sliding of the auxiliary transmission shifter 45a, the rotation of the transmission shaft 42 is output through three speeds, and the rotational power input to the auxiliary transmission shaft 45 is provided in the auxiliary transmission shaft 45. Then, the rotation direction is changed from the front-rear direction to the left-right direction via the gear 47, and input to the differential mechanisms 50L and 50R located behind the mission case 23 described later.

  A part of the output of the engine 3 is connected from the forward / reverse switching mechanism 7 to the PTO counter shaft 49 via the PTO transmission gear 48 and transmitted to the PTO output shaft 91 at the rear of the vehicle 1.

  Next, a specific configuration of the power transmission configuration that distributes the load of the auxiliary transmission shaft on the pinion shaft, which is a feature of the present invention, will be described. FIG. 5 is an enlarged sectional plan view of the vicinity of the differential mechanism in the transmission case, and FIG. 6 is an enlarged plan view of the vicinity of the pinion shaft showing another example of power transmission in which the pinion shaft is divided and arranged.

  Bearings 100L and 100R such as bearings are provided on the pinion shaft 22 and in the vicinity of the left and right ends of the pinion shaft 22 in plan view. The bearings 100L and 100R are inward of the fuselage and near the bearings 100L and 100R. Bearings 101L and 101R are further provided on the left and right on the pinion shaft 22 at positions not in contact with 100L and 100R. The pinion shaft 22 is supported by these bearings 100L, 100R, 101L, 101R and the like.

  Further, both end portions of the gear 21 provided on the pinion shaft 22 are connected to the bearings 101L and 101R so as to mesh with a gear 47 fixed to the rear end of the auxiliary transmission shaft 45. The position where the gear 21 on the pinion shaft 22 meshes with the gear 47 of the auxiliary transmission shaft 45 may be either on the left or right in plan view of the gear 47 as shown in FIGS.

  Here, the driving force of the auxiliary transmission shaft 45 by the power of the engine 3 is transmitted after the auxiliary transmission in the front-rear direction via the gear 47 at the rear end of the auxiliary transmission shaft 45 and the gear 21 fixed to the pinion shaft 22. The motive power is transmitted to the pinion shaft 22 while changing the rotational direction to the left and right direction. At this time, since both ends of the gear 47 are connected to the bearings 101L and 101R, the load on the auxiliary transmission shaft 45 is transferred to the gear. The load that is transmitted to the bearings 101L and 101R via 47 and bends the pinion shaft 22 rearward in the traveling direction of the machine body 1 is not applied.

  Accordingly, since the load in the bending direction applied to the auxiliary transmission shaft 45 toward the rear in the traveling direction is not applied to the pinion shaft 22, bending of the pinion shaft 22 can be prevented. Further, for example, even if the diameter and weight of the auxiliary transmission shaft 45 are increased in order to increase the horsepower even in the same small tractor, the increased load of the auxiliary transmission shaft 45 is dispersed on the pinion shaft 22. The bending of the airframe can be prevented by increasing the diameter and weight of the pinion shaft 22 in order to prevent this bending.

  For example, the gear 21 is linked between a bearing 100L and a bearing 100R provided one by one in the vicinity of both ends of the pinion shaft 22 as in the prior art, so that the load of the auxiliary transmission shaft 45 as described above is applied to the pinion shaft 22. In this case, the bearing 100L supporting the pinion shaft 22 and the bearing 100R are loaded with the gears 25L and 27L or the gears in addition to the loads of the auxiliary transmission shaft 45 and the pinion shaft 22 and the like. Loads such as drive sprockets 60L and 60R and axles 89L and 89R transmitted through 25R and 27R are also applied, and the bearing is damaged early due to overload.

  Therefore, the bearings 100L, 101L and 100R, 101R are provided near the both ends of the pinion shaft 22 and on the left and right, respectively, so that in addition to the loads of the auxiliary transmission shaft 45, the pinion shaft 22, etc. The bearings such as the drive sprockets 60L and 60R and the axles 89L and 89R transmitted via the bearings are supported by the two bearings 100L and 101L or 100R and 101R provided on the left and right sides of the pinion shaft 22, respectively. Can be prevented.

  Further, the pinion shaft 22 can be divided and arranged on the left and right sides from the vicinity of the center so that the load of the auxiliary transmission shaft 45 can be distributed to the pinion shaft. In this case, as shown in FIG. 6, bearings 100L, 101L and 100R, 101R are provided in the vicinity of the outer end portions of the pinion shafts 22L, 22R divided from the center to the left and right, respectively, and are located on the pinion shafts 22L, 22R. The gear 21 is provided between the bearings 101L and 101R so as to cover the inner portions of the pinion shafts 22L and 22R so as to be connected to the bearings 101L and 101R.

  With this configuration, as described above, the load on the auxiliary transmission shaft 45 is transmitted to the bearings 101L and 101R via the gear 21, and the load on the auxiliary transmission shaft 45 is distributed to the pinion shafts 22L and 22R. Since the strength (load resistance) is improved by shortening the lengths of the pinion shafts 22L and 22R, even if the diameter and weight of the auxiliary transmission shaft 45 are increased, the pinion shafts 22L and 22R can be prevented from being bent. In addition, the entire weight of the pinion shafts 22L and 22R is reduced, and the weight of the machine body can be reduced.

  Furthermore, the pinion shafts 22L and 22R whose lengths are arbitrarily set within the cylindrical tooth width of the gear 21 can be divided into left and right parts, and the load of the auxiliary transmission shaft 45 can be distributed to the pinion shafts 22L and 22R. . With such a configuration, the torque transmission surfaces of the pinion shafts 22L and 22R can be arbitrarily set within the cylindrical tooth width of the gear 21, so that the diameter of the auxiliary transmission shaft 45 is increased, for example, from the auxiliary transmission shaft 45 to the pinion. Even if the driving force transmitted to the shafts 22L and 22R is increased, if the pinion shaft 45 is lengthened, the transmission surface meshing with the gear 21 becomes wider, and the torque applied to the pinion shafts 22L and 22R can be kept constant. Therefore, regardless of the horsepower of the tractor 1, the gear 21 and the parts of the bearings 100L, 100R, 101L, 101R can be used widely, and the productivity of the tractor 1 is improved.

  The power after the sub-shift in the front-rear direction is transmitted to the left and right via the gear 47 fixed to the rear end of the sub-transmission shaft 45 and the gear 21 fixed to the central portion of the pinion shaft 22 described above. The direction of rotation is changed to the direction and transmitted to the left and right differential mechanisms 50L and 50R. 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 mechanisms 50L and 50R include sun gears 51L and 51R fixed to the input shafts 20L and 20R, planetary gears 53L and 53R provided around the sun gears 51L and 51R so as to freely revolve, and the planetary gear 53L. , 53R and carriers 55L, 55R that are rotatably fitted to the input shafts 20L, 20R and the axles 89L, 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 airframe 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. However, 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 reverse rotation shafts 43L and 43R respectively reversely rotate the left and right carriers 55L and 55R via differential gears 44L and 44R fixed to one end of the reverse rotation shafts 43L and 43R and carrier gears 56L and 56R. . 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 rotation of the gear mechanism 50 is subtracted, the left and right drive sprockets 60L and 60R rotate at different rotational speeds, thereby turning the airframe 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. It is the structure which turns the body 1 to the other side.

  A plurality of brake plates 29a, which are brake mechanisms 29, are formed on the pinion shaft 22 at one end of the pinion shaft 22. When a brake pedal (not shown) is operated by the driver, the brake arm 28 is In conjunction with the rotation of the brake arm 28, the brake arm 28 generates a brake action and decelerates the machine body 1.

  In particular, the brake plate 29a is located at the right end of the pinion shaft 22, and a brake case (not shown) that houses the brake plate 29a, the brake arm 28, and the like is used as a right rear axle case 80R that houses the right planetary gear mechanism 50R. It can be integrated. 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 airframe 1 can be maintained.

  Furthermore, by disposing the brake mechanism 29 and the turning HST motor 73 separately on the left and right, a link relationship (not shown) constituting the brake mechanism 29 and hydraulic piping (not shown) constituting the turning HST mechanism. Can be arranged separately in the left and right rear axle cases 88L and 88R, and there is an effect that the maintainability of the airframe 1 is improved.

  As described in detail above, the crawler tractor 1 of this example includes the crawler frame 81 that rotatably supports the driven idler 85 at both ends, and the drive sprocket 60 mounted on the axle 89, and the driven idler 85. A crawler type traveling device 80 in which a crawler belt 95 is wound between the drive sprocket 60 and the drive sprocket 60 is provided in the lower part of the machine body 1, and the driving force of the auxiliary transmission shaft 45 by the power of the engine 3 is applied to the rear end of the auxiliary transmission shaft 45. Via the gear 47 provided and the gear 21 provided on the pinion shaft 22, the transmission is transmitted from the pinion shaft 22 to the drive sprocket 60 via the differential mechanism 50, and the gear 21 provided on the pinion shaft 22 is transmitted to the pinion shaft 22. If the bearings 101L and 101R are further provided inside the fuselage 1 of the bearings 100L and 100R, respectively. In, it is to coordinate the gear 21 provided on the pinion shaft 22 bearing provided inside the machine body 1 101L, during 101R. In addition, the pinion shaft 22 is divided and arranged on the left and right sides near the center, and the torque transmission surface of the pinion shaft 22 to which the driving force from the auxiliary transmission shaft 45 is transmitted can be arbitrarily set within the cylindrical tooth width of the gear 21.

  In the above-described example, a small crawler tractor (work vehicle) has been described as an example of a work machine. However, the present invention is not limited to this, and other than a medium or large crawler tractor, a farm work machine It can be applied to any work vehicle equipped with a crawler type traveling device, such as a combine, etc., and a construction machine, such as a 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 of 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 a drive part. It is the cross-sectional top view which expanded the differential mechanism vicinity in a mission case. It is the top view which expanded the pinion shaft vicinity which shows another example of the power transmission which dividedly arranged the pinion shaft. It is a perspective view which shows the conventional small wheel type tractor.

Explanation of symbols

3 Engine 21, 47 Gear 22, 22L, 22R Pinion shaft 25L, 25R, 27L, 27R Gear 45 Sub transmission shaft 60L, 60R Drive sprocket 89L, 89R Axle 100L, 100R, 101L, 101R Bearing

Claims (3)

A crawler type traveling device having a crawler frame that rotatably supports a driven idler at both ends, and a drive sprocket mounted on an axle, and a crawler belt wound around the driven idler and the drive sprocket. The driving force of the auxiliary transmission shaft, which is provided at the lower part of the fuselage and is driven by the engine power, is transmitted from the pinion shaft through a differential mechanism via a gear provided at the rear end of the auxiliary transmission shaft and a gear provided on the pinion shaft. In the crawler work vehicle that transmits to the drive sprocket,
Gears provided on the pinion shaft are linked to bearings provided near both ends of the pinion shaft, and further bearings are provided on the inner sides of the respective bodies of the bearings, and on the pinion shafts between the bearings provided on the inner side of the body. A crawler work vehicle characterized in that a provided gear is linked.   2. The crawler work vehicle according to claim 1, wherein the pinion shaft is divided and arranged on the left and right sides near the center.   The crawler work vehicle according to claim 1, wherein a torque transmission surface of the pinion shaft to which a driving force from the auxiliary transmission shaft is transmitted can be arbitrarily set within a cylindrical tooth width of the gear.

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