JP2007131091A - Working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission device of a working vehicle capable of easily preventing oil leakage and the like when an oil filter is replaced, and improving assembling workability and maintenance workability of the oil filter. <P>SOLUTION: In this working vehicle, a step for an operator to ride is arranged on a traveling machine body, to which an engine, a hydraulic continuously variable transmission gear and the like are installed. An oil filter for supplying working oil to the hydraulic continuously variable transmission gear and the like is detachably arranged on a lower side of the step via a filter bracket. A drain cap for opening/closing a drain port for extracting the working oil is arranged on the bottom of the filter bracket. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hydraulic apparatus such as a hydraulic continuously variable transmission for transmitting traveling power to traveling wheels in a work vehicle such as a tractor used for agricultural work or a wheel loader used for civil engineering work.

  Conventionally, in general, in a work vehicle such as a tractor or a wheel loader described above, when power is transmitted to the left and right traveling wheels, the power is transmitted from an engine mounted on a traveling machine body in the work vehicle via a transmission mechanism of a transmission case. It is comprised so that it may output with respect to the traveling wheel.

In this case, in a conventional work vehicle, a clutch housing and a transmission case are provided on the traveling machine body, a hydraulic continuously variable transmission and a transmission gear mechanism are provided on the transmission case, and the continuously variable transmission is connected to the engine from the engine. Power is transmitted from the continuously variable transmission to the traveling wheel via the transmission gear mechanism (see, for example, Patent Document 1). In addition, a technique is known in which a drain port is provided in the base (engine block) of the oil filter to prevent engine oil from flowing out of the oil filter housing portion of the base when the oil filter is replaced (for example, Patent Document 2). reference).
JP 2004-211776 A JP-A-11-28319

  The prior art is for supplying hydraulic oil to the hydraulic continuously variable transmission at a position close to a charge pump for the hydraulic continuously variable transmission or a position close to the hydraulic continuously variable transmission. Since the oil filter is disposed, it is necessary to assemble the oil filter using the engine, the clutch housing, the transmission case, or the like. For this reason, the oil filter is disposed in a place that is difficult to see from the outside of the machine body and difficult to attach and detach (on the machine body side such as the inside of the bonnet), so that the assembly workability and maintenance workability of the oil filter cannot be improved. There's a problem. For example, when the oil case is used as a hydraulic oil tank of the hydraulic continuously variable transmission and the oil filter is assembled at a location away from the mission case, the oil filter is replaced when the oil filter is replaced. It was necessary to perform an operation for removing the hydraulic oil in the filter in the vicinity of the mission case, and to move to a place away from the mission case to attach and detach the oil filter.

  An object of the present invention is to transmit power in a work vehicle capable of improving the assembly workability and maintenance workability of the oil filter while easily preventing oil leakage when the oil filter is replaced. A device is provided.

  In order to achieve the above object, a power transmission device for a work vehicle according to a first aspect of the present invention includes a step for an operator to board a traveling machine body on which an engine, a hydraulic continuously variable transmission, and the like are mounted. In the work vehicle, an oil filter for supplying hydraulic oil to the hydraulic continuously variable transmission or the like is detachably disposed on the lower surface side of the step via a filter bracket, and is operated at the bottom of the filter bracket. A drain cap for opening and closing the drain port for oil removal is arranged.

  According to a second aspect of the present invention, in the work vehicle according to the first aspect, the oil filter includes a cylindrical filter main body for filtering hydraulic oil, and a filter for detachably incorporating the filter main body. A case, the upper surface of the filter bracket is connected to the lower surface side of the step, the filter case is detachably fixed to the side surface of the filter bracket, and the lower surface of the step and the cylindrical shape of the filter body Are formed substantially parallel to each other in a side view.

  According to a third aspect of the present invention, in the work vehicle according to the second aspect, the filter bracket includes an injection port connected to a hydraulic pump, a discharge port connected to a hydraulic device, and the drain port. The substantially horizontal upper surface of the filter bracket is fixed to the substantially horizontal front end portion of the mounting seat plate protruding from the step by fastening bolts from the upper surface side of the mounting seat plate.

  According to a fourth aspect of the present invention, in the work vehicle according to the third aspect, one end side of a high pressure side oil pipe for injecting hydraulic oil is connected to the injection port, and the operation is performed along a side portion of the traveling machine body. The other end side of the high pressure side oil pipe for oil injection is extended, and the bottom part of the traveling machine body and the bottom part of the oil filter are arranged at substantially the same height in a side view.

  According to a fifth aspect of the present invention, in the work vehicle according to the fourth aspect, the step is protruded on the left and right sides of the traveling machine body, and a low pressure oil filter is provided on the lower surface side of either the left or right of the step. A low pressure side oil pipe is extended along the side of the traveling machine body on the same side as the side where the low pressure oil filter is provided, and a high pressure oil filter is attached to the other lower surface side of the step. A high-pressure side oil pipe is extended along the side surface of the traveling machine body on the same side as the side on which the oil filter is provided.

  According to the first aspect of the present invention, in a work vehicle in which a step for an operator to ride on a traveling body equipped with an engine, a hydraulic continuously variable transmission, and the like is disposed, a filter is provided on a lower surface side of the step. An oil filter for supplying hydraulic oil to the hydraulic continuously variable transmission or the like is detachably disposed via a bracket, and a drain for opening and closing a drain port for draining hydraulic oil at the bottom of the filter bracket. Since the cap is disposed, the operation of attaching and detaching the oil filter and the operation of extracting the hydraulic oil from the drain port are performed in the vicinity of the step that is largely opened toward the outside of the traveling machine body. It can be performed in almost the same place. Therefore, when replacing the oil filter, it is possible to eliminate the trouble of forgetting to remove the hydraulic oil from the drain port, and the operator can easily attach and detach the oil filter with a large work space, Assembling workability and maintenance workability of the oil filter can be improved.

  According to the invention of claim 2, the oil filter has a cylindrical filter main body for filtering the hydraulic oil, and a filter case for detachably incorporating the filter main body. The upper surface of the filter bracket is connected to the lower surface side, the filter case is detachably fixed to the side surface of the filter bracket, and the lower surface of the step and the cylindrical center line of the filter body are viewed in side view. Since it is formed substantially in parallel, the oil filter can be installed in a lateral orientation along the substantially horizontal bottom surface of the step, and the space on the lower surface side of the step is used for easy maintenance. An oil filter can be assembled in a compact manner.

  According to the invention of claim 3, the filter bracket is formed with an injection port connected to a hydraulic pump, a discharge port connected to a hydraulic device, and the drain port, and the mounting seat protruded from the step Since the substantially horizontal upper surface of the filter bracket is fixed to the substantially horizontal tip of the plate by fastening bolts from the upper surface side of the mounting seat plate, the lower side of the step with high rigidity The filter bracket can be easily assembled, and the mechanical vibration of the filter bracket can be easily reduced. Therefore, the oil pipe connected to the injection port and the discharge port can be assembled with a simple mounting structure.

  According to the fourth aspect of the present invention, one end side of a high-pressure side oil pipe for injecting hydraulic oil is connected to the injection port, and the other side of the high-pressure side oil pipe for injecting hydraulic oil along the side of the traveling machine Since the end side is extended and the bottom portion of the traveling machine body and the bottom portion of the oil filter are arranged at substantially the same height in a side view, the top surface side of the oil filter can be protected by the step. And the lower surface side of the oil filter can be protected by the traveling machine body. Therefore, it is possible to easily reduce the damage of the hydraulic oil injection high-pressure side oil pipe or the oil filter due to mud in the field.

  According to the fifth aspect of the present invention, the step is protruded on the left and right sides of the traveling machine body, the low pressure oil filter is attached to the lower surface of either the left or right of the step, and the low pressure oil filter is provided. A low pressure side oil pipe is extended along the side surface of the traveling machine body on the same side as the other side, a high pressure oil filter is attached to the other lower surface side of the step, and the same side as the side on which the high pressure oil filter is provided Since the high pressure side oil pipe is extended along the side surface of the traveling machine body, the low pressure oil filter, the low pressure side oil pipe, the high pressure oil filter, and the The high pressure side oil pipe can be arranged at a large distance. Therefore, the assembly or maintenance work of the low-pressure oil filter and the low-pressure side oil pipe and the assembly or maintenance work of the high-pressure oil filter and the high-pressure side oil pipe can be consciously performed by an operator, Assembling or maintenance workability can be improved.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, drawings when an embodiment of the present invention is applied to a farm tractor as a work vehicle will be described. 1 is a side view of the tractor, FIG. 2 is a plan view of the traveling aircraft body, FIG. 3 is an enlarged plan view of the latter half of the traveling aircraft body, and FIG. 4 is an enlarged plan view of a peripheral portion of a step frame of the traveling aircraft body. 5 is a perspective view of a pedal or the like operated by an operator, FIG. 6 is a sectional side view of the transmission case and the transmission front case, FIG. 7 is a front view of the transmission front case, FIG. 8 is a hydraulic circuit diagram, and FIG. FIG.

  As shown in FIGS. 1 and 2, the tractor 1 supports a traveling machine body 2 with a pair of left and right rear wheels 4 as well as a pair of left and right front wheels 3, and an engine 5 mounted on the front portion of the traveling machine body 2. The two rear wheels 4 and the two front wheels 3 are driven to drive forward and backward. The traveling machine body 2 has an engine frame 8 having a front bumper 6 and a front axle case 7, a clutch housing 10 having a main clutch 9 for interrupting power output from the engine 5, and a speed change of the engine 5 as appropriate. A transmission case 11 for transmitting to the rear wheels 4 and the front wheels 3, a transmission front case 12 for connecting the transmission case 11 to the clutch housing 10, and outward from the outer surface of the clutch housing 10. It comprises a pair of left and right step frames 13 that are detachably mounted so as to protrude.

  The rear end side of the engine frame 8 is connected to the left and right outer surfaces of the engine 5. The front side of the clutch housing 10 is connected to the rear side of the engine 5. The front side of the mission case 11 is connected to the rear side of the clutch housing 10 via a mission front case 12. Further, the front axle case 7 is connected to the engine frame 8 via a rolling shaft 276 penetrating in the traveling direction (see FIG. 9). Therefore, when a difference occurs in the ground pressure between the left and right front wheels 3, the front axle case 7 rotates about the rolling shaft 276, and the left and right front wheels 3 move up and down, so that the ground pressure of the left and right front wheels 3 is increased. Will be maintained approximately equal.

  The engine 5 is covered with a hood 14. A steering column 15 is erected on the upper surface of the clutch housing 10. A steering handle 16 that is steered by moving the front wheels 3 to the left and right is disposed on the upper surface side of the steering column 15. A control seat 17 is disposed on the upper surface of the mission case 11. Flat floor boards 18 are respectively provided on the upper surfaces of the pair of left and right step frames 13 (see FIG. 2). Both front wheels 3 are attached to the engine frame 8 via a front axle case 7. Further, as shown in FIG. 3, both rear wheels 4 are connected to the transmission case 11 via a rear axle case 11a that is detachably mounted so as to protrude outward from the outer surface of the transmission case 11. Installed. The upper surface side of both rear wheels 4 is covered with left and right rear fenders 4a.

  On the upper surface of the transmission case 11, a hydraulic working machine lifting mechanism 20 for lifting and lowering a working machine 19 such as a tiller connected to the rear part of the traveling machine body 2 is detachably attached. Further, a PTO shaft 21 for transmitting a driving force to the work machine 19 is provided on the rear side surface of the transmission case 11 so as to protrude rearward. The work machine 19 is connected to the rear portion of the mission case 11 via a three-point link mechanism 24 including a pair of left and right lower links 22 and one top link 23. When the left and right lift arms 20a of the work implement lifting mechanism 20 are connected to the left and right lower links 22 via lift links and the work implement lift mechanism 20 is operated, the work implement 19 moves up and down.

  A hydrostatic continuously variable transmission (HST) 25 described later is disposed on the front side surface of the mission front case 12. The hydrostatic continuously variable transmission 25 is installed in the rear part of the clutch housing 10. The rotation of the engine 5 is transmitted to the continuously variable transmission 25 via a main drive shaft 26 protruding rearward from the main clutch 9, and then the output from the continuously variable transmission 25 is transmitted by a sub transmission gear mechanism 59 described later. The gears are appropriately shifted and transmitted to the rear wheels 4 and the front wheels 3. On the other hand, the rotation of the engine 5 from the main shaft 26 is transmitted to the PTO output reduction gear mechanism 62 via the PTO transmission shaft 62a and the PTO one-way clutch 62b, and is appropriately decelerated by the PTO output reduction gear mechanism 62. Thus, it is transmitted to the PTO shaft 21.

  Next, with reference to FIG.4 and FIG.5, the structure of the control part which the operator of the control seat 17 operates is demonstrated. A clutch pedal 31 for disengaging the main clutch 9 is disposed on the left side of the control column 15 protruding from the floor plate in front of the control seat 17. The clutch pedal 31 is connected to a clutch disengaging mechanism 31a for disengaging the main clutch 9 and a clutch-containing spring 31b for maintaining the main clutch 9 in a connected state, and the clutch pedal 31 is maintained at the initial position by the clutch-containing spring 31b. Will be.

  On the other hand, a single brake pedal 33 and a single parking brake lever 34 that actuate the left and right rear wheel braking brake mechanisms 32 are disposed to the right of the steering column 15. Left and right rear wheel braking brake mechanisms 32 are connected to the brake pedal 33 via left and right brake rods 32a, and the brake mechanism 32 is activated by the operation of the brake pedal 33, and the left and right rear wheels 4 are braked. It will be. Further, the brake pedal 33 is maintained in the depressed position by the operation of the parking brake lever 34, and the braking of the rear wheel 4 is continued even if the operator lifts his / her foot from the brake pedal 33.

  A brake operation bearing portion 261 is integrally formed on the outside of the bottom portion of the clutch housing 10 by casting. A brake operation shaft 262 is rotatably supported on the brake operation bearing portion 261 (see FIG. 6). The left and right brake rods 32 a are connected to the brake pedal 33 via the brake operation shaft 262. Further, a pedal arm base of the clutch pedal 31 is rotatably fitted on the brake operation shaft 262 (see FIG. 5).

  Further, a forward pedal 36 and a reverse pedal 37 for operating the shift operation trunnion arm 35 of the continuously variable transmission 25, and a cruise lever 38 for maintaining the forward pedal 36 in the operating position are arranged on the right side of the steering column 15. Has been. A trunnion arm 35 is connected to the forward pedal 36 and the reverse pedal 37 via a speed change link mechanism 35a, and the stepless transmission 25 is operated by a stepping operation of the forward pedal 36 or the reverse pedal 37, so that the continuously variable transmission 25 can move forward or reverse. A shifting operation is performed.

  The structure of the clutch housing 10, the transmission front case 12, and the transmission case 11 will be described with reference to FIGS. The interior of the clutch housing 10 is partitioned by a housing inner wall 50 so as to be divided into front and rear, and a housing front chamber 51 and a housing rear chamber 52 are formed inside the clutch housing 10. The interior of the mission front case 12 is partitioned by a front wall 53 so as to be divided into front and rear, and a front case front chamber 54 and a front case rear chamber 55 are formed inside the mission front case 12. The interior of the mission case 11 is partitioned by a mission inner wall 56 so as to be divided into front and rear, and a mission front chamber 57 and a mission rear chamber 58 are formed inside the mission case 11.

  In a closed space formed by the housing rear chamber 52 and the front case front chamber 54, a continuously variable transmission 25 disposed in front of the front wall 53 is provided. In the closed space formed by the front case rear chamber 55 and the mission front chamber 57, an auxiliary transmission gear mechanism 59 and a front wheel drive mechanism 60 are provided. A rear wheel differential gear mechanism 61 and a PTO output reduction gear mechanism 62 are provided inside the mission rear chamber 58. A continuously variable transmission 25 is provided in the housing rear chamber 52 and the front case front chamber 54, and the continuously variable transmission 25 is detachably fixed to the front wall 53 of the transmission front case 12 by a plurality of bolts. ing.

  The front wall 53 of the mission front case 12 is formed with a PTO transmission through hole that communicates the front case front chamber 54 and the front case rear chamber 55. A PTO drive shaft 231 protrudes from the rear surface side of the continuously variable transmission 25 into the rear front case rear chamber 55. Inside the front case rear chamber 55, the rear end side of the PTO drive shaft 231 is detachably connected to the front end side of the PTO transmission shaft 62 a through the coupling 232 in the axial direction.

  Next, the main transmission structure of the continuously variable transmission 25 will be described. The continuously variable transmission 25 includes a transmission hydraulic pump 63 and a transmission hydraulic motor 64 that is operated by the hydraulic pump 63 (see FIG. 7). A front end side of the transmission input shaft 65 of the continuously variable transmission 25 protrudes from the housing front chamber 51 through a through hole 50 a in the housing inner wall 50. The main drive shaft 26 is connected to the front end side of the speed change input shaft 65 through a coupling 66. A main transmission output shaft 67 of the continuously variable transmission 25 protrudes inside the front case rear chamber 55. A main transmission output gear 68 is fitted on the main transmission output shaft 67 through a spline. A counter input gear 70 is fitted on the counter shaft 69 of the auxiliary transmission gear mechanism 59. A counter input gear 70 is engaged with the main transmission output gear 68. The continuously variable transmission output from the main transmission output shaft 67 is transmitted to the counter shaft 69 via the main transmission output gear 68 and the counter input gear 70.

  Next, the auxiliary transmission gear mechanism 59 will be described. The counter shaft 69 is integrally formed with a sub-speed first speed (low speed) counter gear 71 and a sub-speed second speed (medium speed) counter gear 72. Further, a counter shift third speed (high speed) counter gear 73 is fitted to the counter shaft 69 via a spline. Further, the auxiliary transmission gear mechanism 59 includes an auxiliary transmission first speed output gear 74 meshed with the first speed counter gear 71, an auxiliary transmission second speed output gear 75 engaged with the second speed counter gear 72, and a third speed counter gear. And a sub-speed third-speed output gear 76 that meshes with the gear 73. A first speed output gear 74 and a third speed output gear 76 are rotatably fitted to the sub transmission output shaft 77 of the sub transmission gear mechanism 59. The auxiliary transmission output shaft 77 is fitted with an auxiliary transmission slider 78 that is slidable in the axial direction and rotates integrally with the auxiliary transmission output shaft 77 via a spline. A second speed output gear 75 is formed integrally with the auxiliary transmission slider 78.

  Therefore, the second-speed output gear 75 is engaged with the second-speed counter gear 72 by moving the auxiliary transmission slider 78 by operating the auxiliary transmission shifter 79. On the other hand, for the first-speed output gear 74 or the third-speed output gear 76, the auxiliary transmission slider 78 is selectively operated by operating an auxiliary transmission lever (not shown) via the first-speed clutch pawl 80 or the third-speed clutch pawl 81. Connected to That is, the rotation of the auxiliary transmission output shaft 77 is shifted in three stages of low speed, medium speed, and high speed by the first speed output gear 74, the second speed output gear 75, and the third speed output gear 76.

  On the other hand, the rear end side of the auxiliary transmission output shaft 77 protrudes into the mission rear chamber 58. A pinion gear 82 for transmitting a rotational force to the rear wheel differential gear mechanism 61 is integrally formed on the rear end side of the auxiliary transmission output shaft 77. The power from the auxiliary transmission output shaft 77 is transmitted to the left and right rear wheels 4 via the pinion gear 82 and the differential gear mechanism 61.

  Next, the front wheel drive mechanism 60 will be described. A front wheel drive take-out shaft 85 of the front wheel drive mechanism 60 is connected to the front end side of the auxiliary transmission output shaft 77 via a four-wheel drive small diameter gear 83 and a four-wheel drive large diameter gear 84. On the rear end side of the front wheel drive take-out shaft 85 protruding into the front case rear chamber 55, a four-wheel drive large-diameter gear 84 that is rotatably fitted, and the four-wheel drive large-diameter gear 84 is driven for the front wheel. A front wheel output clutch 86 for detachably engaging with the take-out shaft 85 is disposed. The middle portion and the rear end side of the front wheel drive take-out shaft 85 are supported by the front wall 53.

  Further, the front end side of the front wheel drive take-out shaft 85 protrudes into the front case front chamber 54. The rear end side of the front wheel transmission shaft 88 is connected to the front end side of the front wheel drive take-out shaft 85 via a first universal shaft joint 250. The front end side of the front wheel transmission shaft 88 is extended toward the front side of the traveling machine body 2, and the driving force is transmitted from the front end side of the front wheel transmission shaft 88 to the front wheel 3 via the front axle case 7. . The front wheel transmission shaft 88 is fitted with a shaft cover 89 made of synthetic resin pipe, and the front wheel transmission shaft 88 is protected by the shaft cover 89.

  As shown in FIG. 7, a front wheel drive take-off shaft 85, which will be described later, is disposed between the continuously variable transmission 25 and the transmission link mechanism 35a. That is, the hydraulic continuously variable transmission 25 is fixed to the transmission front case 12 while being inclined toward the right side of the traveling machine body 2 in a front view. A space for installing the front wheel drive take-off shaft 85 can be easily secured in the transmission front case 12 with the link mechanism 35a.

  Accordingly, the transmission link mechanism 35a disposed on the right side of the traveling machine body 2 in the traveling direction and the lower end side of the trunnion arm 35 disposed on the right side of the hydraulic continuously variable transmission 25 are brought close to each other, thereby 10 right side walls can be arranged to face each other. In addition, the right side surface of the hydraulic continuously variable transmission 25 and the upper end side of the trunnion arm 35 can be brought close to each other, and a trunnion shaft for supporting the trunnion arm 35 on the hydraulic continuously variable transmission 25 can be formed in a short length. .

  The bellows-shaped insertion portion on one end side of the shaft cover 89 is detachably locked in the cover insertion hole 258 at the bottom of the clutch housing 10 made of casting, while the input shaft case 7a on the rear surface side of the front axle case 7 is detachably locked. The other end side of the shaft cover 89 is connected via a synthetic rubber boot 255. Therefore, the driving force to the front wheel 3 is transmitted from the front wheel drive take-out shaft 85 to the front axle case 7 via the front wheel transmission shaft 88 in the shaft cover 89.

  FIG. 8 shows a hydraulic circuit 200 of the tractor 1 of the present embodiment, and includes a working machine hydraulic pump 94 and a charging hydraulic pump 95 that are operated by the rotational force of the engine 5, as will be described later. The charging hydraulic pump 95 is connected to a double-acting steering hydraulic cylinder 202 for power steering by the steering handle 16 via a steering control valve 201 for power steering. The working machine hydraulic pump 94 is connected to a lifting hydraulic switching valve 204 for supplying hydraulic oil to a single-acting lifting hydraulic cylinder 203 in the working machine lifting mechanism 20.

  Therefore, the operator operates the position lever 205 to switch the lifting hydraulic switching valve 204 to operate the lifting hydraulic cylinder 203 and rotate the lift arm 20a, so that the work machine 19 is connected via the lower link 22. Will be raised or lowered.

  As shown in FIG. 8, the variable displacement shift hydraulic pump 63 of the hydraulic continuously variable transmission 25 described above, and a constant displacement shift hydraulic pressure that operates with high-pressure hydraulic fluid discharged from the hydraulic pump 63. The suction side and discharge side of the motor 64 are connected via a closed loop oil passage 207. By adjusting the angle of the swash plate 208 of the transmission hydraulic pump 63 driven via the transmission input shaft 65 with the forward pedal 36, the reverse pedal 37 or the main transmission lever (not shown), the transmission hydraulic motor 64 is controlled. The number of rotations of the main transmission output shaft 67 driven through the change is changed.

  As shown in FIG. 8, the hydraulic circuit 200 described above includes a relief valve, a flow rate adjustment valve, a check valve, an oil cooler, an oil filter, and the like. A strainer 210 inside the transmission case 11 as a hydraulic oil tank is connected to the suction side of the working machine hydraulic pump 94 and the charging hydraulic pump 95 via a low-pressure line filter 209. A charge oil passage 211 in which a steering control valve 201 for power steering is arranged is connected to the discharge side of the charge hydraulic pump 95. The charge oil passage 211 is connected to the closed loop oil passage 207 via the steering control valve 201 and the check valves 212 and 213. While the engine 5 is operating, the hydraulic oil from the charging hydraulic pump 95 is always replenished to the closed loop oil passage 207.

  The tank port side of the steering control valve 201 for power steering and the closed loop oil passage 207 are connected by a charge oil passage 211. A pipe-type oil cooler 214 and a high-pressure line filter 215 connected to the downstream side of the oil cooler 214 are disposed in the charge oil passage 211 in the middle of connecting the steering control valve 201 and the closed loop oil passage 207. ing. A charge oil passage 211 between the downstream side of the high-pressure line filter 215 and the check valves 212 and 213 is connected to the transmission case 11 via a relief valve 216. When there is excess hydraulic oil in the charge oil passage 211 to be supplied from the charging hydraulic pump 95 to the closed loop oil passage 207, the hydraulic oil in the charge oil passage 211 is returned to the mission case 11 via the relief valve 216. .

  That is, the hydraulic oil inside the mission case 11 circulates inside the mission case 11 and the charge oil passage 211 via the charging hydraulic pump 95, the pipe-type oil cooler 214, the high-pressure line filter 215, and the relief valve 216. Will be. Therefore, the hydraulic oil inside the mission case 11 is appropriately cooled to a temperature by the pipe-type oil cooler 214 in the middle of the charge oil passage 211, removed by the high-pressure line filter 215, and returned to the inside of the mission case 11. Become.

  As shown in FIG. 2, the above-described low-pressure line filter 209 is detachably disposed via a filter mounting frame 217 on the lower surface side of the left step frame 13 on the left side of the machine body in the traveling (forward) direction. . The above-described high-pressure line filter 215 is detachably disposed via a filter mounting bracket 218 on the lower surface side of the right step frame 13 on the right side of the machine body in the traveling (forward) direction. The working machine hydraulic pump 94 and the charging hydraulic pump 95 described above are installed in a pump case 219 disposed on the outer surface of the engine 5 in the vicinity of the left engine frame 8 on the left side of the machine body in the traveling (forward) direction. .

  On the other hand, as shown in FIGS. 2 and 11, the steering control valve 201 described above is provided in a unit case 220 for power steering disposed on the upper surface of the clutch housing 10. The first high-pressure pipe 221 for forming a part of the charge oil passage 211 extends along the left engine frame 8 on the left side of the machine body and is connected to the charge hydraulic pump 95 and the steering control valve 201. . On the other hand, the low pressure pipe 222 connected to the suction side of the working machine hydraulic pump 94 and the charging hydraulic pump 95 and the transmission case 11 extends along the left side of the traveling machine body 2 such as the left engine frame 8 on the left side of the machine body. ing. A low pressure filter 209 is connected in the middle of the extension of the low pressure pipe 222.

  On the other hand, as shown in FIGS. 2 and 8, a water-cooling radiator 226 is placed on the upper surface of the engine frame 8 in front of the engine 5. A pipe-type oil cooler 214 is detachably disposed on the front surface of the radiator 226 with a bolt or the like. A second high pressure pipe 223, a third high pressure pipe 224, and a fourth high pressure pipe 225 for forming a part of the charge oil passage 211 are provided on the right side of the traveling machine body 2 such as the right engine frame 8 on the right side of the machine body in the traveling direction. It is extended along. The second high pressure pipe 223 is connected to the steering control valve 201 and the pipe type oil cooler 214. The third high pressure pipe 224 is connected to the pipe type oil cooler 214 and the high pressure line filter 215. The fourth high-pressure pipe 225 is connected to the high-pressure line filter 215 and the continuously variable transmission 25 (closed loop oil passage 207).

  Next, an embodiment of the present invention will be described with reference to FIGS. The cooling fan 227 is disposed on the front surface of the engine 5 described above, and the air outside of the traveling vehicle body 2 is moved to the engine 5 side via the pipe-type oil cooler 214 and the radiator 226 by the intake action of the cooling fan 227. It is captured. That is, the pipe-type oil cooler 214, the radiator 226, and the like are cooled by the external air taken in from the front side of the oil cooler 214 by the cooling fan 227.

  As shown in FIG. 14, the pipe-type oil cooler 214 includes a meandering pipe portion 263 as an oil cooler body, an injection side pipe portion 264 that connects one end side to both ends of the meandering shape pipe portion 263, and a discharge side pipe. Part 265. Through the openings 267 and 268 of the radiator installation table 266 on the upper surface side of the engine frame 8, the other end sides of the injection side pipe unit 264 and the discharge side pipe unit 265 are penetrated from the upper surface side of the radiator installation table 266 to the lower surface side. is doing. A second high-pressure pipe 223 is detachably connected to the other end side of the injection-side pipe portion 264 via an oil pipe joint 269. In addition, the third high-pressure pipe 224 is detachably connected to the other end side of the discharge side pipe portion 265 via an oil pipe joint 270. The oil pipe joint 270 has a fastening structure using three bolts and one nut, but may be formed by a one-touch detachable coupling type joint.

  On the back side of the meandering pipe portion 263 described above, a horizontally elongated upper mounting frame 271 and a lower mounting frame 272 are fixed, and on the front surface of the radiator 226 erected substantially vertically on the radiator installation base 266, The upper mounting frame 271 and the lower mounting frame 272 are fastened with the two bolts 273. A mounting plate 274 is fixed to the horizontally long discharge side pipe portion 265, and the mounting plate 274 is fastened to the lower portion of the front surface of the radiator 226 with a bolt 275. A pipe-type oil cooler 214 is detachably disposed on the front surface of the radiator 226 via five bolts 273 and 275.

  As shown in FIGS. 10, 14, and 15, the oil pipe joints 269 and 270 are disposed in the vertical width of the engine frame 8 in the vicinity of the outer surface of the right engine frame 8 in the forward (forward) direction. The second high-pressure pipe 223 and the third high-pressure pipe 224 are arranged. That is, the above-described front axle case 7 is rotatably disposed on the engine frame 8 via the rolling fulcrum shaft 276, and left and right stoppers at the lower end of the engine frame 8 so that the ground pressures of the left and right front wheels 3 are substantially equal. In the structure in which the front axle case 7 is rotated within the regulation range of 277, a pipe locking tool 278 is fixed to the outer surface of the engine frame 8 so as to be detachable by a bolt 279, and the second high pressure is connected to the pipe locking tool 278. The extending middle portions of the pipe 223 and the third high-pressure pipe 224 are supported, and the second high-pressure pipe 223 and the third high-pressure pipe 224 are extended along the side surface of the engine frame 8.

  Accordingly, the oil pipe joints 269, 270, the second high-pressure pipe 223, and the third high-pressure pipe 224 are disposed at a position higher than the stopper 277, and even if the front axle case 7 rotates, the second high-pressure pipe 223 is provided. And the front axle case 7 does not contact the third high-pressure pipe 224. The front axle case 7 and the engine frame 8 protect the oil pipe joints 269, 270, the second high-pressure pipe 223, and the third high-pressure pipe 224.

  As apparent from FIGS. 2, 10, and 14, the engine 5 and the hydraulic continuously variable transmission 25 are mounted on the traveling machine body 2, and the front wheel 3 is mounted on the engine frame 8 as a front chassis of the traveling machine body 2. And an oil cooler 214 for cooling the hydraulic oil such as the hydraulic continuously variable transmission 25, the injection side of the oil cooler 214 on either the left or right outer side of the engine frame 8 An injection pipe part 264 as an oil pipe connection part and a discharge side pipe part 265 as a discharge side oil pipe connection part are projected, and the injection pipe part 264 and the discharge side pipe part 265 of the oil cooler 214 are connected via oil pipe joints 269 and 270. Since the second high pressure pipe 223 as the injection side oil pipe and the third high pressure pipe 224 as the discharge side oil pipe are detachably connected, the engine frame 8 The injection pipe portion 264 and the discharge side pipe portion 265 can be arranged so as to be exposed on the outer surface, and the operator can be positioned on the outer side of the traveling machine body 2 and the oil pipe joints 269 and 270 can be attached and detached from the outer side of the traveling machine body 2 . Therefore, separation or connection work of the second high-pressure pipe 223 and the third high-pressure pipe 224 can be easily performed, and assembly workability and maintenance workability of the oil cooler 214 can be improved.

  As is apparent from FIGS. 10 and 14, the meandering pipe portion 263 of the oil cooler 214 is fixed to the front surface of the radiator 226 in front of the engine 2, and the injection pipe portion 264 and the exhaust pipe are disposed at both ends of the meandering pipe portion 263. Since the side pipe part 265 is formed, the oil cooler 214 can be compactly arranged upright and compactly on the upper surface side of the engine frame 8 via the radiator 226, and the radiator serves as a support means for the meandering pipe part 263. The mounting structure of the oil cooler 214 can be easily configured using the H.226.

  As is apparent from FIGS. 10 and 15, the oil pipe joints 269 and 270 are disposed within the vertical width of the engine frame 8, along the outer surface of the engine frame 8, and toward the rear of the traveling machine body 2. Since the high-pressure pipe 223 and the third high-pressure pipe 224 are extended, the oil pipe joints 269, 270, the second high-pressure pipe 223, and the third high-pressure pipe 224 are made compact using the outer surface of the engine frame 8. For example, the second high-pressure pipe 223 and the third high-pressure pipe 224 can be supported at a position away from the steering mechanism (the steering hydraulic cylinder 202 and the hydraulic hose connected thereto) of the front wheel 3.

  As is apparent from FIGS. 9, 10, and 12, the left and right step frames 13 protrude from the side surface of the traveling machine body 2 in the left-right direction, and the first step frame 13 is approximately the same height as the engine frame 8. 3 A high-pressure line 215 is extended, a high-pressure line filter 215 as a high-pressure oil filter is connected to the oil cooler 214 via the third high-pressure line 224, and the high-pressure line filter 215 is disposed on the lower surface side of the step frame 13. Therefore, the third high-pressure pipe 224 can be extended substantially linearly in the front-rear direction of the traveling machine body 2, and the piping structure of the third high-pressure pipe 224 can be easily configured.

  As is apparent from FIGS. 2, 9, and 11, the low pressure line filter 209 is disposed below the step frame 13 opposite to the side where the high pressure line filter 215 is disposed, and the low pressure line filter 209 is provided. The charge hydraulic pump 95 is disposed in the pump case 219 on the side of the engine 5 on the same side as the engine 5, and the charge hydraulic pump 95 is connected to the low pressure line filter 209 via the low pressure pipe 222 as the low pressure side oil pipe. Since the low-pressure pipe 222 is extended along the side surface of the traveling machine body 2 on the same side as the side where the hydraulic pump 95 is provided, the low-pressure pipe 222 is substantially linear toward the front-rear direction of the traveling machine body 2. The piping structure of the low-pressure piping 222 can be easily configured.

  The attachment structure of the high-pressure line filter 215 as an oil filter will be described with reference to FIGS. The vertical end side of the L-shaped mounting seat plate 280 is fixed to the rear surface side of the step frame 13 by welding. The substantially horizontal upper surface of the filter mounting bracket 218 is detachably fastened to the lower surface on the horizontal end side of the mounting seat 280 protruding rearward from the step frame 13 with a bolt 281. A substantially horizontal upper surface of the filter mounting bracket 218 is connected to the lower surface side of the step frame 13 as a step through a mounting seat plate 280.

  As shown in FIG. 13, the one end side of the above-described third high-pressure pipe 224 is connected to the injection port 282 on the left side in the traveling direction of the filter mounting bracket 218 via a pipe joint 283. One end side of the above-described fourth high-pressure pipe 225 is connected to the discharge port 284 on the upper surface side of the filter mounting bracket 218 via a pipe joint 285. A drain port 286 is formed at the bottom of the filter mounting bracket 218, and a bolt-shaped drain cap 287 is detachably screwed to the drain port 286.

  As shown in FIG. 13, the high-pressure line filter 215 includes a cylindrical filter body 215a for filtering hydraulic oil from the third high-pressure pipe 224, and a filter case 215b for internally installing the filter body 215a. Consists of. A filter case 215b in a lateral orientation is detachably screwed to the substantially circular front side of the filter mounting bracket 218. The substantially horizontal lower surface of the step frame 13 and the cylindrical center line of the filter body 215a are formed substantially parallel in a side view. In addition, the filter main body 215a is provided in the filter case 215b so that the cylindrical center line of the filter main body 215a is substantially parallel to the center line in the front-rear direction of the traveling machine body 2 (see FIG. 10).

  When the drain port 286 is disposed at a position lower than the bottom of the filter case 215b fixed to the filter mounting bracket 218 and the drain cap 287 is detached from the drain port 286, the hydraulic oil in the filter case 215b flows out from the drain port 286. Will do. Therefore, when replacing the filter body 215a, the hydraulic oil in the filter case 215b is removed from the drain port 286 before removing the filter case 215b, so that when the filter case 215b is removed, the operation in the filter case 215b is performed. Oil does not leak. Further, the replacement work of the filter main body 215a and the extraction work of extracting the hydraulic oil in the filter case 215b from the drain port 286 can be performed at substantially the same place on the outer side of the step frame 13. The replacement operation and the extraction operation can be performed with little movement of the operator. It is possible to prevent an operator from forgetting the extraction operation and performing the replacement operation.

  As is clear from the above description and FIGS. 2 and 13, the step frame 13 as a step for the operator to ride is disposed on the traveling machine body 2 on which the engine 5 and the hydraulic continuously variable transmission 25 are mounted. In this work vehicle, a high-pressure line filter 215 as an oil filter for supplying hydraulic oil to the hydraulic continuously variable transmission 25 and the like via the filter bracket 218 is detachably disposed on the lower surface side of the step frame 13. Since the drain cap 287 for opening and closing the drain port 286 for draining the hydraulic oil is disposed at the bottom of the filter bracket 218, the operation of attaching and detaching the high-pressure line filter 215 and the hydraulic oil from the drain port 286 are arranged. The step frame 13 in the vicinity of the step frame 13 that is largely opened toward the outside of the traveling machine body 2 It can be carried out in substantially the same location. Therefore, when replacing the high-pressure line filter 215, the trouble of forgetting to remove the hydraulic oil from the drain port 286 can be eliminated, and the operator can secure a large work space and easily attach and detach the high-pressure line filter 215. Thus, the assembly workability and maintenance workability of the high-pressure line filter 215 can be improved.

  As is clear from the above description and FIGS. 9 and 13, the high-pressure line filter 215 includes a cylindrical filter body 215a for filtering hydraulic oil, and a filter case for detachably incorporating the filter body 215a. 215b, the upper surface of the filter bracket 218 is connected to the lower surface side of the step frame 13 on the right side in the traveling direction, and the filter case 215b is detachably fixed to the side surface of the filter bracket 218. Since the lower surface and the cylindrical center line of the filter main body 215a are formed substantially parallel to each other in a side view, the high-pressure line filter 215 is placed sideways along the substantially horizontal bottom surface of the step frame 13. A high-pressure line that can be installed and is easy to maintain using the space on the underside of the step frame 13 It is possible to assemble the Iruta 215 to the compact.

  As apparent from the above description and FIGS. 10 and 13, the filter bracket 218 includes an injection port 282 connected to the charging hydraulic pump 95 and a discharge port connected to the hydraulic continuously variable transmission 25 as a hydraulic device. 284 and a drain port 286 are formed, and a substantially horizontal top surface of the filter bracket 218 is formed at a substantially horizontal front end portion of the mounting seat plate 280 projecting from the step frame 13, and a bolt from the upper surface side of the mounting seat plate 280. Since it is fixed by fastening 281, the filter bracket 218 can be easily assembled to the lower side of the highly rigid step frame 13, and the mechanical vibration of the filter bracket 218 can be easily reduced. Therefore, oil pipes (the third high-pressure pipe, the fourth high-pressure pipe 225, etc.) connected to the injection port 282 and the discharge port 284 can be assembled with a simple mounting structure.

  As is clear from the above description and FIGS. 9 and 10, one end side of the third high-pressure pipe 224 as a high-pressure side oil pipe for hydraulic oil injection is connected to the injection port 282, and along the side portion of the traveling machine body 2. Since the other end side of the third high-pressure pipe 224 is extended and the bottom portion of the traveling machine body 2 and the bottom portion of the high-pressure line filter 215 are arranged at substantially the same height in a side view, the step frame 13 Thus, the upper surface side of the high pressure line filter 215 can be protected, and the lower surface side of the high pressure line filter 215 can be protected by the traveling machine body 2. Therefore, it is possible to easily reduce the damage of the third high-pressure pipe 224 or the high-pressure line filter 215 due to mud in the field.

  As is clear from the above description and FIGS. 2, 10, 11, and 12, the step frame 13 protrudes from the left and right sides of the traveling machine body 2, and the low pressure is applied to the lower surface of either the left or right of the step frame 13. A low pressure line filter 209 as an oil filter is attached, and a low pressure pipe 222 as a low pressure side oil pipe is extended along the side surface of the traveling machine body 2 on the same side as the side where the low pressure line filter 209 is provided. Since the high pressure line filter 215 is attached to the other lower surface side, the third high pressure pipe 224 is extended along the side surface of the traveling machine body 2 on the same side as the side where the high pressure line filter 215 is provided. The low-pressure line filter 209 and the low-pressure pipe 222, and the high-pressure line filter 215 and the third high-pressure pipe 224 can be arranged at a large distance across the airframe 2. . Therefore, the operator can consciously perform the assembly or maintenance work of the low-pressure line filter 209 and the low-pressure pipe 222 and the assembly or maintenance work of the high-pressure line filter 215 and the third high-pressure pipe 224. Maintenance workability can be improved.

  Note that the filter mounting frame 217 (mounting seat) is protruded from the left step frame 13 in the traveling direction. A low-pressure line filter 209 as an oil filter for supplying hydraulic oil to the charging hydraulic pump 95 via the filter bracket 209a is detachably disposed on the filter mounting frame 217. Similar to the high pressure line filter 215 described above, the lower surface of the step frame 13 and the cylindrical center line of the filter body 215a are substantially the same as the lower surface of the step frame 13 and the center line of the low pressure line filter 209 in a side view. They are formed in parallel. Therefore, the low-pressure line filter 209 can be compactly installed in a horizontal orientation along the substantially horizontal bottom surface of the step frame 13, and the low-pressure line filter 209 is compactly positioned at a position where maintenance is easy using the space on the lower surface side of the step frame 13. Can be assembled to.

  As shown in FIG. 16, an injection side valve 288 is connected between the injection side pipe portion 264 and the oil pipe joint 269. Further, a discharge side valve 289 is connected between the discharge side pipe portion 265 and the oil pipe joint 270. When removing the oil pipe joints 269 and 270, the injection side valve 288 and the discharge side valve 289 are first switched to the closed state, so that even if the oil pipe joints 269 and 270 are removed, the injection side pipe part 264 or the discharge side pipe part 265 is removed. The hydraulic oil in the oil cooler 214 does not leak. Therefore, when disassembling the oil cooler 214, the second high-pressure pipe 223, or the third high-pressure pipe 224, it is possible to prevent leakage of hydraulic oil from the oil cooler 214. Therefore, the oil cooler 214, the second high-pressure pipe 223, or the third high-pressure pipe 224 can be prevented. The high-pressure pipe 224 can be easily separated, and the disassembly workability of the oil cooler 214 or each of the pipes 223 and 224 can be improved.

  In addition, the meandering pipe part 263, the injection side pipe part 264, and the discharge side pipe part 265 described above are formed of a metal pipe with good heat conductivity such as a copper alloy, an iron alloy, or an aluminum alloy. In addition, the diameter of the low-pressure pipe 222 formed by a synthetic resin pipe, a metal pipe, or a combination of these pipes is larger than the diameter of the first to fourth high-pressure pipes 221, 223, 224, 225 formed by a metal pipe. Is formed in a size of about twice or more.

It is the whole tractor side view. It is a top view of the traveling body of a tractor. It is an enlarged plan view of the latter half part of the traveling machine body. It is an enlarged plan view of the peripheral part of the step frame of the traveling machine body. It is a perspective view of the pedal etc. which an operator operates. It is a section side view of a mission case and a mission front case. It is front explanatory drawing of a mission front case. It is a hydraulic circuit diagram. It is a bottom view of a traveling machine body. It is side views, such as an oil cooler and a high pressure line filter. It is a perspective view from the lower side of a low-pressure line filter and a high-pressure line filter. It is a perspective view from back upper direction, such as a low voltage | pressure line filter and a high voltage | pressure line filter. It is a perspective view from diagonally backward upper direction, such as a step frame and a high voltage line filter. It is a perspective view from diagonally forward upper direction, such as an oil cooler. It is a perspective view from diagonally forward downward, such as an oil cooler. It is side views, such as an oil cooler and an oil pipe joint.

Explanation of symbols

2 traveling body 5 engine 13 step frame (step)
25 Hydraulic continuously variable transmission (hydraulic equipment)
95 Hydraulic pump for charging 209 Low pressure line filter (oil filter for low pressure)
215 High pressure line filter (High pressure oil filter)
215a Filter body 215b Filter case 222 Low-pressure pipe (low-pressure side oil pipe)
224 Third high-pressure pipe (high-pressure side oil pipe)
280 Mounting seat plate 281 Bolt 282 Inlet port 284 Discharge port 286 Drain port 287 Drain cap

Claims (5)

In a work vehicle in which a step for boarding an operator on a traveling body mounted with an engine, a hydraulic continuously variable transmission, and the like is provided.
An oil filter for supplying hydraulic oil to the hydraulic continuously variable transmission or the like is detachably disposed on the lower surface side of the step via a filter bracket,
A work vehicle characterized in that a drain cap for opening and closing a drain port for extracting hydraulic oil is disposed at the bottom of the filter bracket.   The oil filter has a cylindrical filter body for filtering hydraulic oil and a filter case for detachably incorporating the filter body, and the upper surface of the filter bracket is connected to the lower surface side of the step. The filter case is detachably fixed to the side surface of the filter bracket, and the lower surface of the step and the cylindrical center line of the filter body are formed substantially parallel in a side view. The work vehicle according to claim 1.   In the filter bracket, an injection port connected to a hydraulic pump, a discharge port connected to a hydraulic device, and the drain port are formed, and the mounting seat plate protruding from the step has a substantially horizontal tip, The work vehicle according to claim 2, wherein a substantially horizontal upper surface of the filter bracket is fixed by fastening bolts from the upper surface side of the mounting seat plate.   One end side of a high-pressure side oil pipe for injecting hydraulic oil is connected to the injection port, and the other end side of the high-pressure side oil pipe for injecting hydraulic oil is extended along a side portion of the traveling machine body. The work vehicle according to claim 3, wherein a bottom portion of the oil filter and a bottom portion of the oil filter are arranged at substantially the same height in a side view. Protruding the step on the left and right sides of the traveling machine body, attaching a low pressure oil filter to the lower surface of either the left or right side of the step, and the side of the traveling machine body on the same side as the side where the low pressure oil filter is provided. A low pressure side oil pipe is extended along the side surface, a high pressure oil filter is attached to the other lower surface side of the step, and along the side surface of the traveling machine body on the same side as the side where the high pressure oil filter is provided. The work vehicle according to claim 4, wherein a high-pressure side oil pipe is extended.

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