JP2020037406A - Work vehicle - Google Patents

Abstract

To provide a work vehicle having a layout of a machine body that can be common to a wheel tractor, a crawler tractor and the like, without requiring an additional hydraulic fluid tank to be newly arranged.SOLUTION: A hydraulic piping device 40 which connects a transmission case 5 provided at a rear part of a machine body to a transmission case 6 for slewing provided at a front part of the machine body and circulates, is provided along a longitudinal direction of the machine body, and an intermediate part in the longitudinal direction, of the machine body of the hydraulic piping device 40 is used as a tank part 42 and hydraulic fluid is stored in the tank part 42. A suction filter 47 is incorporated in the tank part 42. Further, the hydraulic piping device 40 is arranged in a space between a frame of the machine body and a track frame 21 of a crawler type running device, in a lateral direction of the machine body.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a work vehicle.

  Patent Literature 1 discloses a configuration of a crawler tractor including a pair of left and right crawler traveling devices. Here, a turning method in which turning is performed by utilizing the speed difference between the right and left crawlers is employed, and a hydraulic hydraulic continuously variable transmission for turning is mounted. For this reason, the required amount of hydraulic oil is ensured by storing hydraulic oil also used as lubricating oil in the transmission case and providing a dedicated hydraulic oil tank connected to the transmission case.

Japanese Patent No. 4694717

  Crawler tractors equipped with conventional crawler-type traveling devices have been designed based on a design concept dedicated to crawler tractors, but from the viewpoint of reducing the overall manufacturing cost of tractors including wheel tractors and crawler tractors, the frame structure is reduced. It is demanded that the tractor be shared by other types of tractors, or that parts be shared and used. That is, there is an increasing demand for manufacturing a crawler tractor based on the structure of a wheel tractor whose production is large.

  In particular, the required amount of hydraulic oil is secured while following the body layout of the wheel tractor, in that a predetermined amount of hydraulic oil must be secured in the hydraulic continuously variable transmission for turning of the crawler type traveling device. However, it is difficult to arrange the hydraulic oil tank while taking into consideration prevention of air suction when the body is tilted. Furthermore, in the case of small and medium-sized tractors, since the body is being made more compact, there is no extra space, and it is difficult to arrange a hydraulic oil tank having a new desired capacity.

  Along with a hydraulic piping device that connects and circulates a rear transmission case provided at the rear of the fuselage and a front transmission case provided at the front of the fuselage, the hydraulic piping device is provided along the longitudinal direction of the fuselage, and an intermediate portion of the hydraulic piping device in the longitudinal direction of the vehicle is provided. This is a work vehicle configured to be a tank unit and to store hydraulic oil in the tank unit.

  A suction filter was built in the tank part.

  The hydraulic piping device is disposed in a space between a body frame and a track frame of the crawler traveling device in a lateral direction of the body.

  ADVANTAGE OF THE INVENTION According to this invention, it is not necessary to arrange | position a hydraulic oil tank newly, and it can implement | achieve the work vehicle which has a machine body layout which can be shared with a wheel tractor, a crawler tractor, etc.

The side view of a crawler tractor. The perspective view which shows the frame structure of a crawler tractor. The perspective view which shows the frame structure of a crawler tractor. The top view which shows a hydraulic piping apparatus. The perspective view of an equalizer. The perspective view of an equalizer. The rear view which shows a rear housing. FIG. 3 is a perspective view of a rear housing. The perspective view which shows an axle case. The figure which shows the relationship between an engine and the mission case for turning. FIG. 2 is a skeleton diagram showing a power transmission path of the crawler tractor. The figure which shows the structure of a reduction shaft. FIG. 4 is an end view showing an internal transmission structure of a turning mission case. The figure which shows a part of assembly of the turning mission case. The figure which shows the method of taking in power to the turning mission case. The figure which shows a brake link structure. The hydraulic circuit diagram of a crawler tractor.

  The crawler tractor 1 will be described with reference to FIGS. The crawler tractor 1 includes a pair of left and right crawler traveling devices 2, a body frame 3 supported by the crawler traveling device 2, an engine 4 and a transmission case 5 mounted on the body frame 3, a turning mission case 6, and , A hood 7 covering the engine 4, a cabin 8 provided behind the hood 7, and the like. The transmission case 5 is disposed at the rear end of the machine body. A PTO shaft 9 projects from the rear surface of the transmission case 5, and power is transmitted via the PTO shaft 9 to a working machine mounted behind the tractor. The turning mission case 6 is arranged at the front end of the fuselage.

  In the crawler tractor 1, the power of the engine 4 is transmitted to the transmission case 5, and after being shifted by a straight HST attached to the transmission case 5, the power is transmitted to the turning transmission case 6 via a drive shaft extending in the longitudinal direction of the vehicle. Power is transmitted. Then, the power input by the turning HST attached to the turning transmission case 6 is shifted to output different rotation speeds to the left and right crawler traveling devices 2. As described above, the crawler tractor 1 employs a turning method that utilizes the speed difference between the left and right crawler traveling devices 2 during turning (details will be described later).

  The body frame 3 includes a pair of left and right plate bodies extending in the vehicle body front-rear direction, and a reinforcing body that connects the left and right plate bodies. The engine 4 is supported on a front frame 3a constituting the front part of the body frame 3, and the transmission case 5 is supported on a rear frame 3b constituting the rear part. The transmission case 5 is fixed between the left and right plates of the body frame 3 and forms a highly rigid frame structure by the body frame 3 and the transmission case 5. As described above, the body frame 3 has a divided structure in which the front frame 3a and the rear frame 3b are connected back and forth, and the engine 4 is fixed to the front frame 3a, and the transmission case 5 is fixed to the rear frame 3b. The assemblability of the frame structure has been improved.

  The crawler traveling device 2 is provided as a pair on the left and right sides of the body. The crawler type traveling device 2 includes a track frame 21, a driving sprocket 22, a tension roller 23, a free wheel 24, a guide roller 25, a crawler belt 26, and the like. The track frame 21 is provided outside the body frame 3. The track frame 21 extends in the front-rear direction of the machine body, and front portions of the left and right track frames 21 are connected by a front beam 27, and rear portions thereof are connected by a rear beam 30.

  The front end of the track frame 21 is fixed to an axle case 31 provided on the side of the turning transmission case 6, and a tension frame 28 that can expand and contract in the front-rear direction is connected to the rear end. The tension roller 23 is rotatably supported by the tension frame 28. The drive sprocket 23 is fixed to an output shaft protruding from the axle case 31. The idler wheels 24 are provided at two positions, a front portion and a rear portion, of the track frame 21, and are rotatably supported by an equalizer frame 29, which is supported at the lower portion of the track frame 21 so as to swing back and forth. I have. The guide roller 25 is rotatably provided at an upper part of the track frame 21 in the front and rear direction. The crawler belt 26 is wound around the driving sprocket 22, the tension roller 23, the idler wheel 24, and the guide roller 25.

  The lubricating oil stored in the transmission case 5 is used as hydraulic oil for the straight HST and the turning HST. The hydraulic oil is circulated between the transmission case 5 and the turning transmission case 6 via a hydraulic piping device 40. The system of the hydraulic piping device 40 includes a hydraulic pump for supplying hydraulic oil.

  The hydraulic piping device 40 is a hydraulic piping structure that connects the transmission case 5 at the rear of the vehicle and the turning transmission case 6 at the front of the vehicle, and is provided along the vehicle front-rear direction of the crawler tractor 1. The hydraulic piping device 40 includes a feed-side suction pipe 41 disposed on one side (right side in the present embodiment) of the machine body from the transmission case 5 and a return-side reduction pipe 51 disposed on the other side. The suction pipe 41 and the reduction pipe 51 are hydraulic pipes for communicating and connecting the mission case 5 and the turning mission case 6 (and the turning HST). The suction pipe 41 and the reduction pipe 51 are arranged between the body frame 3 and the track frame 21 in the lateral direction of the machine, and are arranged above the track frame 21 in the machine vertical direction.

  An intermediate portion of the suction pipe 41 in the longitudinal direction of the fuselage is configured as a tank section 42 formed by a pipe having a larger diameter than other parts of the pipe (a front pipe section and a rear pipe section). Similarly, an intermediate portion of the reduction pipe 51 in the longitudinal direction of the machine is also configured as a tank section 52 formed by a pipe having a larger diameter than other parts of the pipe (a front pipe section and a rear pipe section). That is, in the hydraulic piping device 40, the diameter of a part of the hydraulic piping connecting the transmission case 5 and the turning transmission case 6 is increased, and the capacity is partially increased to be used as a hydraulic oil tank.

  The suction pipe 41 includes a rear pipe 43 connected to the transmission case 5, a front pipe 44 connected to the turning HST 93, and a tank section 42. The rear pipe 43 and the front pipe 44 are configured by pipes having a smaller diameter than the tank section 42. The front end of the tank portion 42 is fixed on the front beam 27 via a stay 45. The rear end of the tank portion 42 is fixed to the rear frame 3b via a bracket 46.

  The reduction pipe 51 includes a front pipe 53 connected to the turning HST 93, a rear pipe 54 connected to a rear housing 70 attached to the transmission case 5, and a tank 52. The front pipe 53 and the rear pipe 54 are formed by pipes smaller in diameter than the tank 52. The front end of the tank 52 is fixed on the front beam 27 via a stay 55. The rear end of the tank 52 is fixed to the rear frame 3b via a bracket 56. The tank section 42 of the suction pipe 41 and the tank section 52 of the reduction pipe 51 are arranged at symmetrical positions centered on the center in the longitudinal direction of the fuselage, and their fixed positions are also arranged at symmetrical positions.

  As described above, the hydraulic piping device 40 is configured to include the suction pipe 41 having the tank part 42 in the middle part in the front and rear, and the reduction pipe 51 having the tank part 52 in the middle part in the front and rear part. 52 functions as a hydraulic oil tank. As a result, in the crawler tractor 1 having the straight HST and the turning HST, the amount of hydraulic oil required for stable operation of the hydraulic continuously variable transmission is ensured. By increasing the diameter of a part of the hydraulic piping to have the function of a hydraulic oil tank, it is not necessary to separately provide a hydraulic oil tank when mounting the turning HST. Further, since there is no need to prepare a space for installing the hydraulic oil tank, it can be easily adopted regardless of the size of the tractor.

  Therefore, the layout of the wheel tractor having no crawler-type traveling device is changed as little as possible (for example, a hydraulic piping device 40 extending in the longitudinal direction of the vehicle is added to the space between the vehicle frame 3 and the track frame 21). In addition, it is possible to design the body layout of the crawler tractor 1 including the crawler type traveling device 2. By reducing the number of different parts, it is possible to use parts in common. For example, when designing the body layout of the crawler tractor 1 from the body layout of the wheel tractor, the configuration of the crawler-type traveling device 2 is added. It is only necessary to arrange the hydraulic piping device 40 in the surplus space. That is, a surplus space generated when manufacturing the crawler tractor can be effectively utilized, and a unique effect that it is not necessary to change other parts is provided.

  Further, by configuring the tank portions 42 and 52 as hydraulic oil tanks with large-diameter pipes, the surface area in contact with air can be made larger than that of a normal pipe portion. This has a specific effect that a reduction in temperature can be expected.

  A suction filter 47 is built in the tank portion 42 of the suction pipe 41. That is, the suction filter 47 is provided on the take-out side at the downstream end of the tank portion 42 configured as a large-diameter pipe. Since the tank portion 42 as the hydraulic oil tank of the present embodiment is a large-diameter pipe, the suction filter 47 can be provided coaxially with the circulation path. Therefore, unlike a conventional rectangular parallelepiped container-type hydraulic oil tank, there is no need to provide an external suction filter, and there is no pressure on the space. In addition, by forming the tank portion 42 as a part of a large-diameter pipe, removal of the hydraulic pipe is facilitated, so that the maintainability of the suction filter 47 can be improved.

  A part of the hydraulic pipe extending in the longitudinal direction of the fuselage is formed as a tank portion 42, 52 and is used as a hydraulic oil tank, so that the robustness with respect to the fuselage inclination is high and air suction into the hydraulic oil can be reduced. It is. Further, a return filter can be similarly built in the tank section 52 of the reduction pipe 51.

  As shown in FIGS. 5 and 6, the equalizer 60 including the idler wheel 24 and the equalizer frame 29 is provided with a reinforcing plate 61. The equalizer 60 is configured to be swingable around the rotation support shaft 62 in the longitudinal direction of the machine body. The swing range of the equalizer 60 is regulated by the abutment of the reinforcing plate 61 with the track frame 21.

  In this way, by bending the front and rear ends of the plate for reinforcing the equalizer 60 to form a contact surface with the track frame 21, the reinforcing plate 61 can also be used as a stopper for rotation control. . Conventionally, a shaft is provided for a stopper, but the reinforcing plate 61 also serves as a stopper, so that the shaft is not required.

  As shown in FIGS. 7 and 8, a rear housing 70 is attached to both left and right sides of the transmission case 5. In the wheel tractor, a rear housing 70 is provided in the crawler tractor 1 at a position corresponding to a place where the rear axle case is provided. The inside of the rear housing 70 communicates with the transmission case 5, and the lubricating oil stored in the transmission case 5 can also flow through the rear housing 70. In other words, by installing the rear housing 70, the amount of oil that can be stored in the transmission case 5 and the rear housing 70 can be increased.

  An oil detection window 71 is provided on a part of the rear surface of the rear housing 70 on one side (the right side in the present embodiment) on the left and right sides. The oil detection window 71 is provided in the middle part of the rear housing 70 in the upper and lower directions, and is provided at a position where the oil level of the hydraulic oil stored in the transmission case 5 and the rear housing 70 can be confirmed to be low. By confirming the oil amount in the transmission case 5 through the oil inspection window 71, it is possible to secure the oil amount required for each hydraulic system.

  The transmission case 5 and the rear housing 70 are respectively fixed by bolting or the like. The rear housing 70 is fixed to the rear beam 30 by bolting or the like. That is, the transmission case 5 is supported by the rear beam 30 via the rear housings 70. The rear housing 70 supports the cabin 8 and the fuel tank 72. The fuel tank 72 is attached to the rear housing 70 via a support stay 73.

  As described above, the rear housing 70 provided on both sides of the transmission case 5 of the crawler tractor 1 has functions such as a function as a hydraulic oil tank, a calibration function by an oil inspection window 71, a function to support the cabin 8 and the fuel tank 72, and the like. By attaching various functions, it is not necessary to separately provide each member, and the number of components can be reduced.

  As shown in FIG. 9, the axle cases 31 and 40 attached to the left and right of the transmission case 5 have the same configuration. Although it is necessary to provide a drain hole for maintenance at the lower part of the axle case, the axle case 31 of the present embodiment has a symmetrical shape, and a drain hole 41 is provided symmetrically at the lower end of the case, and the axle case 31 is provided on the right side. By using the drain hole 41 located on the lower side as a drain hole for maintenance when assembled on the left side and the left side, parts are shared.

  Thus, by adopting the same components for the left and right axle cases 31, the number of component types can be reduced, the manufacturing cost can be reduced, and the component management cost can be reduced. Further, it is possible to prevent erroneous assembly due to similar parts that may occur when different parts are used on the left and right.

  As shown in FIG. 10, the turning mission case 6 is disposed below the front of the engine 4, and the upper surface of the turning mission case 6 is formed to be inclined downward from the front to the rear. Thereby, the wind from the front of the turning transmission case 6 flows along the upper surface, so that the wind can be circulated toward the engine oil pan 75 located at the lower part of the engine 4. Engine oil can be cooled.

  As described above, by taking the outer shape of the turning mission case 6 into consideration of the flow of the wind, it is not necessary to separately install a wind direction plate, and the number of parts can be reduced. In addition, the circulation of the wind around the engine 4 can be improved with a simple device.

  Next, a power transmission configuration of the crawler tractor 1 will be described with reference to FIG.

  After projecting rearward from the engine 4, power is transmitted from an output shaft 80 to a pump shaft 81 and a PTO clutch 82 in the transmission case 5. The power is transmitted from the PTO clutch 82 to the PTO shaft 9 through a PTO transmission 83. The straight HST 84 is arranged on the pump shaft 81. The motor shaft 85 of the straight HST 84 is formed in a pipe shape, and is disposed on the pump shaft 81. Power is transmitted from the motor shaft 85 to a transmission shaft 88 via a transmission shaft 87 provided with a forward / reverse switching clutch 86. A first-speed, second-speed, and third-speed clutches are provided on the transmission shaft 88, respectively. The output from the speed change shaft 88 is transmitted to an input bevel shaft 91 of the turning transmission case 6 via a transmission shaft and a transmission gear.

  Power is transmitted from a front output shaft 92 protruding forward from the engine 4 to a pump shaft 94 of the turning HST 93. The turning HST 93 is attached to the front of the turning mission case 6. The movable swash plate of the turning HST 93 is linked to a steering handle in the cabin 8. The motor shaft 95 of the turning HST 93 extends into the turning transmission case 6, and a bevel gear 96 is fixed to an end thereof. The bevel gear 96 meshes with left and right bevel gears 97, and power of forward rotation is transmitted to one of them and reverse rotation to the other from the motor shaft 95. Power is transmitted from the bevel gears 97 to the carriers 99 of the left and right planetary gear mechanisms 98 forming a forced differential.

  Power is transmitted from the input bevel shaft 91 to the differential input shaft 100 of the planetary gear mechanism 98. A sun gear 101 of a planetary gear mechanism 98 is fixed to an end of the differential input shaft 100, and the sun gear 101 is meshed with a planetary gear 102. The planetary gear 102 is rotatably supported on a carrier shaft of the carrier 99. The power is transmitted from the planetary gear mechanism 98 to the drive shaft 104 of the drive sprocket 22 via the reduction shaft 103.

  When the steering wheel is in a straight running state, the turning HST 93 is in a neutral state, the motor shaft 95 is not rotated, and the output after the transmission is shifted by the transmission case 5 is transmitted to the drive shaft 104, and the left and right rotation speeds are equal. Go straight. When the steering handle is rotated left or right, the movable swash plate of the turning HST 93 is tilted in accordance with the rotation direction and the rotation angle, and the output rotation direction and the number of rotations are output to the motor shaft 95 in accordance with the tilt. Then, forward rotation is applied to one of the left and right bevel gears 97 from the motor shaft 95 to the planetary gear mechanism 98 to increase the speed, and reverse rotation is applied to the other planetary gear mechanism 98 to reduce the speed. In this way, the crawler tractor 1 employs the turning method by changing the output to the left and right crawler traveling devices 2 according to the rotation of the steering handle.

  As shown in FIG. 12, the deceleration shaft 103 in the axle case 31 is not divided at an intermediate portion, but is configured as a single shaft. The deceleration shaft 103 is a final deceleration shaft that outputs the rotational power shifted by the turning transmission case 6 to the input shaft of the drive sprocket 22. As described above, by integrating the conventional deceleration shaft 103 having the divided structure, the number of assembling steps can be reduced and the productivity can be improved. Also, unlike the split structure, the number of bearings supporting the reduction shaft 103 can be reduced, and the number of parts can be reduced.

  As shown in FIGS. 11 and 13, the parking plate friction plate 105 is not disposed on the input bevel shaft 91, but is disposed on a separately provided brake shaft 106, and a mechanism for applying a brake via the brake shaft 106 is adopted. Has adopted. A brake gear 107 is fixed to the brake shaft 106. This brake gear 107 meshes with a brake gear 108 on the input bevel shaft 91 side. The mechanism is such that the rotation of the input bevel shaft 91 is stopped via the brake gears 107 and 108 by stopping the rotation of the brake shaft 106 by operating the friction plate 105.

  By providing the mechanism of the parking brake at a position one axis away from the input bevel shaft 91 in this manner, a space around the input bevel shaft 91 can be given a margin. Further, since the drive shaft serving as the output shaft from the transmission case 5 and the input bevel shaft 91 can be coaxially arranged, a straight type drive shaft can be adopted.

  Further, as shown in FIG. 14, as the parking brake mechanism, the friction transmission plate 105, the brake shaft 106, and the brake gear 107 are sub-assembled, and the input transmission bevel shaft 91 and the brake gear 108 are assembled. Can be assembled, and assemblability can be improved.

  Further, as shown in the upper diagram of FIG. 15, as a method of taking power into the turning transmission case 6, a method of directly inputting the power from the input bevel shaft 91 to the bevel gear 109 and transmitting the power to the differential input shaft 100, and a method of FIG. As shown in the figure below, by preparing two types of input from the brake shaft 106 to the bevel gear 110 via the brake gears 107 and 108 and the input bevel shaft 91, depending on the size of the crawler tractor 1, the type of the tractor, and the like. It can be changed on the fly. In this way, by preparing a plurality of methods for taking in the power to the turning mission case 6, it is possible to enhance the diversion of the mission case which is expensive when a new work is performed, and to reduce the cost.

  As shown in FIG. 16, a universal joint 112 is connected to a camshaft 111 for operating a parking brake, and an arm 113 for rotating the universal joint 112 and inputting torque to the camshaft 111 is provided. The arm 113 is connected to the universal joint 112 via a rotating piece 114. The arm 113 extends into the cabin 8 and is connected to a brake pedal 116 in the cabin 8 via a link mechanism 115. When the brake pedal 116 is depressed, the link mechanism 115 rotates so as to lift the arm 113 upward, and as the arm 113 moves, the turning piece 114 is turned clockwise. Then, the universal joint 112 rotates clockwise to rotate the cam shaft 111 in the same direction. In this manner, the operation of the brake pedal 116 becomes a torque input via the arm 113 and is transmitted to the universal joint 112 and the cam shaft 111.

As described above, since the arm 113 is connected via the universal joint 112 instead of extending the arm directly from the camshaft, there is no need to provide a space around the camshaft 111, and the degree of freedom in layout is ensured. be able to.

  Next, a hydraulic circuit of the crawler tractor 1 will be described with reference to FIG.

  The lubricating oil stored in the transmission case 5 is used as hydraulic oil for the straight HST 84, the turning HST 93, the work implement elevating device, the hydraulic clutch, and the like. Power from the rear output shaft 80 of the engine 4 drives a hydraulic pump 120 for pumping hydraulic oil to the lifting device, and a hydraulic pump 121 for pumping hydraulic oil to the straight HST 84 and the PTO clutch 82. Power from the front output shaft 92 of the engine 4 drives a hydraulic pump 122 that pumps hydraulic oil to the turning HST 93. As described above, the hydraulic piping device 40 is provided between the transmission case 5 and the turning transmission case 6, and the hydraulic pump 122 drives the rear piping 43, the tank 42, It is supplied to the turning HST 93 through the suction pipe 41 including the front pipe 44. Then, the turning HST 93 is returned to the transmission case 5 through the reduction pipe 51 including the front pipe 53, the tank 52, and the rear pipe 54.

  1: crawler tractor, 2: crawler traveling device, 3: body frame, 5: transmission case, 6: turning transmission case, 21: truck frame, 40: hydraulic piping device, 41: suction piping, 42: tank portion, 43: rear pipe, 44: front pipe, 47: suction filter, 51: reduction pipe, 52: tank part, 53: front pipe, 54: rear pipe

Claims (3)

Along with a hydraulic piping device that circulates by connecting a rear transmission case provided at the rear of the fuselage and a front transmission case provided at the front of the fuselage along the longitudinal direction of the fuselage,
The middle part in the longitudinal direction of the hydraulic piping device is a tank part,
A work vehicle having a configuration in which hydraulic oil is stored in the tank section.   The work vehicle according to claim 1, wherein a suction filter is built in the tank portion.   The work vehicle according to claim 1, wherein the hydraulic piping device is disposed in a space between a body frame and a track frame of the crawler traveling device in a lateral direction of the body.

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