JP5808027B2 - Farm vehicle transmission - Google Patents

Description

  The present invention relates to an engine, a hydraulic transmission mechanism for inputting a driving force output from the engine, a driving force output from the engine and a driving force output from the hydraulic transmission mechanism, and the combined synthesis. The present invention relates to a transmission device for a farm vehicle provided with a forward gear / reverse gear mechanism for switching a drive force to a forward drive force or a reverse drive force for output.

  Conventionally, the driving force of the engine is input to the pump shaft of the hydraulic transmission mechanism, and the motor shaft of the hydraulic transmission mechanism and the gear to be connected to the pump shaft are connected to the combined output shaft via the planetary gear mechanism, and the hydraulic transmission There is a technique of providing a planetary gear mechanism that rotates a combined output shaft in one direction within a range in which the mechanism can be shifted (Patent Document 1).

JP-A-5-60202

  Conventionally, gear transmission has high power transmission efficiency, but there is a problem that the operability cannot be improved by stepped shifting. In addition, the hydraulic continuously variable transmission mechanism has excellent operability due to the continuously variable transmission that can start from zero, with the initial speed starting from zero, but there is a limit to the power transmission efficiency and there is a problem that the power loss at low speed increases. is there. A belt type continuously variable transmission mechanism using a V-belt and a pulley can perform a highly efficient continuously variable transmission, but there is a problem that the initial speed cannot start from zero. For example, in a work vehicle such as a tractor, the ability to run on wet fields (muddy road surface), smooth entry / exit of the field, shift operation with less shock, start operation that does not require a clutch, speed adjustment adapted to the situation such as work or paddy surface, etc. There is a demand for high power transmission efficiency, continuously variable transmission capable of zero start, and simple gear shifting operation. Furthermore, by combining and outputting the output of the hydraulic transmission mechanism and the gear transmission output by the differential action of the planetary gear mechanism to transmit the engine output, a high power transmission efficiency and a continuously variable transmission capable of zero start can be obtained. When the speed is set so that the combined output from the planetary gear mechanism can move forward and backward (forward / reverse) with the stop (zero) in mind, the reverse shift side of the combined output is reduced and the reverse output is performed. It is possible to increase the forward shift region and output forward, so that the hydraulic shift output can be configured to be highly efficient at normal working speeds. When the speed changes, the combined output stop (zero) position moves backward or forward, and forward or reverse output occurs when the shift operation position is stopped. There is a condition. Therefore, electrical control for automatically adjusting the stop (zero) position of the composite output is required, and there is a problem that the structure is complicated and the manufacturing cost is increased.

However, the agricultural vehicle transmission device according to the first aspect of the present invention includes an engine (2), a hydraulic transmission mechanism (57) for inputting a driving force output from the engine (2), and an output from the engine (2). The forward drive gear (87) and the reverse gear for outputting the combined drive force to the forward drive force or the reverse drive force by combining the drive force to be output and the drive force output from the hydraulic transmission mechanism (57). (88) mechanism, and when the hydraulic transmission mechanism (57) is shift-controlled to the highest speed position in the reverse rotation state, the traveling speed is set to zero, and the hydraulic transmission mechanism ( 57), as the shift control is performed from the highest speed position in the reverse rotation state to the highest speed position in the forward rotation state via the neutral position where the output stops, the traveling speed is increased steplessly. It is configured, when the traveling speed is zero When the ratio of the driving force of the engine (2) and the driving force of the hydraulic transmission mechanism (57) is made equal and the traveling speed is other than zero, the engine is more effective than the driving force of the hydraulic transmission mechanism (57). The ratio of the driving force (2) is set large .

According to the present invention, the engine (2), the hydraulic transmission mechanism (57) for inputting the driving force output from the engine (2), the driving force output from the engine (2) and the hydraulic transmission mechanism (57). And a forward gear (87) / reverse gear (88) mechanism that outputs the synthesized combined driving force by switching to the forward driving force or the backward driving force. When the hydraulic transmission mechanism (57) is shift-controlled to the highest speed position in the reverse rotation state, the traveling speed is set to be zero, and the hydraulic transmission mechanism (57) is set to the highest speed in the reverse rotation state. The shift speed is increased steplessly from the position through the neutral position where the output stops to the highest speed position in the forward rotation state, and the travel speed is zero. When the driving force of the engine (2) and the The ratio of the driving force of the pressure transmission mechanism (57) is made equal, and when the traveling speed is other than zero, the ratio of the driving force of the engine (2) is larger than the driving force of the hydraulic transmission mechanism (57). Since it is set, the characteristics of the engine (2) of the farm vehicle for rated driving can be effectively used to ensure the output torque at the time of zero start, and the slow speed performance can be easily improved. In particular, it is possible to improve the runnability on mud road surfaces such as wet fields, and to ensure a sufficient escape ability with respect to the level difference of the cultivator. Further, the transmission power from the engine (2) having good power transmission efficiency at the work speed can be effectively used, and the work efficiency on the mud road surface can be improved.

Whole side view of rice transplanter. Overall plan view of rice transplanter. The side view of a traveling vehicle body. The top view of a traveling vehicle body. The side view of a vehicle body frame. Side surface explanatory drawing of a drive part. Plane explanatory drawing of a drive part. Side surface explanatory drawing of a side clutch operation system. Plane explanatory drawing of a side clutch operation system. Sectional drawing of a mission case. The enlarged view. Explanatory drawing of a planetary gear mechanism. Partial view of the mission case. Sectional drawing of a planetary gear mechanism. The perspective view from the front of a speed-change pedal part. The perspective view from the rear upper side of a shift pedal part. Gear arrangement explanatory drawing of a mission case. The side view of a hydraulic transmission operation arm part. Explanatory drawing of the neutral state of gear transmission. Explanatory drawing of the reverse drive state of gear transmission. Explanatory drawing of the planting driving state of gear shifting. Explanatory drawing of the PTO idling state of gear shifting. Explanatory drawing of the moving travel state of gear shifting. Rotation explanatory drawing of a planetary gear mechanism. Engine output explanatory drawing. Engine output explanatory drawing of low speed driving. Explanatory drawing of engine output for medium speed running. Explanatory drawing of engine output of high speed running. The output explanatory view of a hydraulic speed change mechanism. The output explanatory view by the side of the transmission gear. The output explanatory view of a synthetic output shaft. Shift explanatory drawing of a shift pedal. FIG. 4 is a correlation diagram between a hydraulic shift output and a gear shift output. FIG. 34 is a correlation diagram between the output of FIG. 33, hydraulic pressure loss, and gear loss.

  Embodiments of the present invention will be described below in detail with reference to the drawings. 1 is a side view of the whole, FIG. 2 is a plan view of the same, FIG. 3 is a side view of a vehicle body frame, FIG. 4 is a plan view of the body, and 1 is a traveling vehicle on which an operator rides. Mounted on the vehicle body frame 3, the front wheel 6 for paddy field traveling is supported on the side of the transmission case 4 via the front axle case 5, and the rear wheel 8 for paddy field traveling is supported on the rear axle case 7 behind the transmission case 4. The spare seedling stage 10 is attached to both sides of the bonnet 9 that covers the engine 2 and the like, and the mission case 4 and the like are covered by a vehicle body cover 11 on which an operator rides, and a seat frame 12 is disposed above and behind the vehicle body cover 11 via a seat frame 12. A driver's seat 13 is attached, and a steering handle 14 is provided at the rear of the bonnet 9 in front of the driver's seat 13.

  In the figure, reference numeral 15 denotes a planting part having a seedling mounting table 16 for five-row planting and a plurality of seedling planting claws 17. The planting case 20 is supported by the planting case 20 through the lower rail 18 and the guide rail 19 so as to be slidable in the left and right directions, and a rotary case 21 that rotates at a constant speed in one direction is supported by the planting case 20. A pair of nail cases 22 and 22 are arranged at symmetrical positions around the axis, and seedling planting nails 17 and 17 are attached to the tips of the nail cases 22 and 22.

  Further, the hitch bracket 23 on the front side of the planting case 20 is connected to the rear side of the traveling vehicle 1 through an elevating link mechanism 26 including a top link 24 and a lower link 25, and the planting unit 15 is moved up and down via the link mechanism 26. The hydraulic lifting cylinder 27 is connected to the lower link 25, and the front and rear wheels 6 and 8 are driven to move, and at the same time, the seedlings 16 are slid back and forth, and one seedling is planted by the planting claws 17. It is configured to carry out rice transplanting work to take out and plant seedlings continuously.

  In the figure, 28 is a main transmission lever, 29 is a planting lift lever, 30 is a brake pedal, 31 is a transmission pedal, 32 is a differential lock pedal, 33 is a sensitivity adjustment lever, and 34 is stopped at an arbitrary height position of the planting part 15. The stop lever 35 is a unit clutch lever 35. The shift and elevating levers 28 and 29, the brakes and the shift pedals 30 and 31 are disposed in the vicinity of the steering handle 14, and the sensitivity adjustment and adjustment are performed in the vicinity of the position of the driver seat 13. Stop and unit clutch levers 33, 34 and 35 and a differential lock pedal 32 are provided.

Further, in the figure, 36 is a center float for leveling of one strip, 37 is a side float for leveling of two strips, 38 is a float 36 through the flexible conveying hose 41 by using the blowing force of the blower 40 for fertilizer in the fertilizer hopper 39. -It is a 5-way side strip fertilizer machine which makes it discharge to 37 side strip groover 42.
3 to 5, the vehicle body frame 3 is divided into a front frame 43, an intermediate frame 44, and a rear frame 45. The engine 2 is connected to the pair of left and right front frames 43, and the pair of left and right intermediate frames 44. A front axle case 5, a pair of left and right rear frames 45 are provided with a rear axle case 7 and a fuel tank 46 for supplying fuel to the engine 2. A front frame 47 and a base frame 48 are provided between the front side and the middle of the front frame 43. Are connected to form a quadrangular frame shape in plan view, and the engine 2 is mounted on the fixed bracket 49 and the base frame 48 via vibration-proof rubber.

  In addition, the intermediate rising portion 50 of the rear frame 45 is connected in a substantially parallel manner by the pipe frame 51 and the portal frame 52, and the rear end of the portal frame 53 in which the left and right lower ends are fixed to the rear axle case 7 is integrally connected. The fuel tank 46 is disposed between the left and right rising portions 50.

  Further, the front and rear ends of the left and right intermediate frame 44 are detachably fixed to the rear end of the front frame 43 and the front end of the rear frame 45 via bolts 54, and the left and right front axle cases are fixed to the lower surface of the left and right intermediate frames 44 via bolts 55. The left and right front axle case 5 is connected and fixed to the transmission case 4.

  As shown in FIGS. 6 to 9, a power steering case 56 is provided on the front left side of the transmission case 4 and a continuously variable hydraulic transmission mechanism 57 is provided on the right side of the case 4. And the pump shaft 58 is connected to the transmission shaft 59 in the front-rear direction at the lower side of the engine 2, and the transmission shaft 59 is connected to the output shaft 60 of the engine 2 via the transmission belt 61. Two outputs are transmitted to the hydraulic transmission mechanism 57.

  Further, the transmission case 4 and the rear axle case 7 are integrally connected by a connecting frame 62 made of pipe on the center line in the longitudinal direction of the vehicle body, and the rear output shaft 63 and the PTO output shaft 64 are projected to the rear of the transmission case 4 so that the rear axle is The rear output shaft 63 is connected via a rear transmission shaft 66 to a rear input shaft 65 that protrudes forward of the case 7, and power is transmitted from the traveling output shaft 63 to the left and right rear wheels 8. Further, the PTO output shaft 64 is connected via a universal joint shaft 69 to an intermediate shaft 68 provided on the bearing 67 at the upper part of the rear axle case 7, and the intermediate shaft 68 is connected to the input shaft of the planting case 20 via a universal joint shaft. Power is transmitted from the PTO output shaft 64 to the planting unit 15.

  Further, as shown in FIGS. 10 to 19, the mission case 4 includes a main body barrel 70, a front lid portion 71, and a rear lid portion 72, and each lid portion 72 is detachably attached to the front and rear of the trunk portion 70. A partition wall portion 73 that divides the inside of the body portion 70 into the front and the rear is provided. Further, the hydraulic transmission mechanism 57 is attached to the front surface of the front lid portion 71, a small-diameter transmission gear 74 is supported on the pump shaft 58 that protrudes into the transmission case 4, and the transmission gear 74 is attached to the front lid portion 71 as a bearing bearing. Then, the power of the transmission gear 74 is transmitted via the pipe shaft 76 to the charge pump 75 that is fixed to the rear surface of the rear lid portion 72.

  Further, a sun gear 78 is supported on the motor shaft 77 of the hydraulic transmission mechanism 57 that protrudes into the transmission case 4, and the sun gear 78 is bearing-supported on the front lid 71, and the small-diameter transmission gear 74 is large. The carrier gear 79 having a diameter is always meshed with the boss of the sun gear 78 and the carrier gear 79 is supported on the free rotation shaft. And a ring gear 82 that meshes with the planetary gear 80 is provided, and the planetary gear mechanism 83 is formed by the gears 78, 80, and 82.

  Further, the sun gear 78 and the rear cover portion 72 are rotatably supported on the front and rear of the combined output shaft 84, and the ring gear 82 is supported on the combined output shaft 84 to be engaged with the hydraulic pump 85 of the hydraulic transmission mechanism 57. And the forward / reverse rotation output, which is a continuously variable hydraulic shift output of the hydraulic motor 86, and the reduced rotation output (one-way constant rotation) of the transmission gear 74 and the carrier gear 79 are combined by the differential action of the planetary gear mechanism 83 to obtain zero. Or transmitted to the combined output shaft 84 as a rotational force in one direction at the maximum speed.

  Furthermore, a forward gear 87 and a reverse gear 88 are supported on the combined output shaft 84 as idle shafts, and the gears 87 and 88 are selectively engaged with the combined output shaft 84 by a slider 89 to output forward, neutral or reverse. In addition, the rear output shaft 63 is bearing-bearing on the partition wall portion 73 and the rear lid portion 72. In addition, a front output shaft 92 that transmits power to the left and right front axles 91 via a differential gear 90 and a counter shaft 94 that supports the PTO transmission gear 93 are provided. Further, the reverse power of the reverse gear 88 is transmitted to the front output shafts 63 and 92 via the output gears 95 and 96, and the front and rear wheels 6 and 8 are driven to move backward, and the moving gear 97 and the planting gear 98 are connected to the rear output shaft 63. The idler shaft is supported, and the gears 97 and 98 are selectively engaged with the rear output shaft 63 by the auxiliary transmission slider 99.

  Further, the moving gear 97 is always meshed with the forward gear 87 via the high speed gear 100 of the counter shaft 94, and the planting gear 98 is always meshed with the low speed PTO transmission gear 93 of the counter shaft 94, as shown in FIG. Under this condition, the power of the forward gear 87 is transmitted to the output shafts 63 and 92 through the gears 100, 93 and 98, and the front and rear wheels 6 and 8 are driven forward at the seedling planting work speed. In addition, under the state of FIG. 22, both the moving gear 97 and the planting gear 98 are in an idle state, so that the planting claw 17 and the like can be manually rotated by the operator to remove the clogged seedlings. While enabling manual rotation of the PTO output shaft 64, the power of the forward gear 87 is transmitted to the output shafts 63 and 92 via the gears 100 and 97 under the state of FIG. The front and rear wheels 6 and 8 are driven forward at a high moving speed.

  Further, as shown in FIG. 11, the power of the PTO transmission gear 93 is transmitted to the PTO output shaft 64 via the PTO transmission shaft 101 and the PTO transmission mechanism 102 to drive the planting portion 15 so as to be able to shift between the stocks. The fertilizer output shaft 104 is connected to the PTO output shaft 64 via the chain 103 installed in the plant, and the fertilizer machine 38 is driven in synchronization with the planting unit 15. Further, as shown in FIG. 12, the transmission case 4 is provided with an oil gauge 105, and as shown in FIG. 13, the sliders 89 and 99 are locked to the same shift fork 106, and the shift lever 28 is switched by five positions. Switch between forward / reverse and sub-shift (low / high speed). Further, as shown in FIGS. 15 to 17, the hydraulic speed change operation arm 109 is connected to the swash plate 107 of the hydraulic pump 85 via the control shaft 108, and the speed change pedal 31 is connected to the arm 109 via the rod 110. The spring 111 for automatically returning the pedal 31 to the stop (zero speed) position when the pedal 31 is released is connected to the arm 109, and the oil damper 112, which is a constant speed operating member, is connected to the arm 109. When the foot is released from the pedal 31 that has been stepped on, the pedal 31 returns at a gentle and substantially constant speed due to the resistance of the oil damper 112 and the return force of the spring 111, and the operation gradually decreases. Instead of the oil damper 112, a constant speed operation member may be formed by a gas spring or the like.

  Further, as shown in FIG. 24, when the pedal 31 is returned to the stop (zero speed) position by the spring 111 with the foot away from the pedal 31, the sun gear 78 reverses clockwise at the maximum rotation and the planetary gear. At the same time, the carrier gear 79 is rotated by the transmission gear 74 to rotate the planetary gear 80 in the counterclockwise direction, and the planetary gear 80 is rotated in the clockwise direction to rotate counterclockwise. , And the composite output shaft 84 is stopped and maintained. When the pedal 31 is stepped on to the middle position (medium speed range) against the spring 111, the sun gear 78 stops, the carrier gear 79 is rotated by the transmission gear 74, and the planetary gear 80 is rotated clockwise. Then, the combined output shaft 84 is rotated by the gear power of the transmission gear 74. Further, when the pedal 31 is fully depressed, the sun gear 78 rotates in the counterclockwise direction at the maximum rotation, and the planetary gear 80 rotates in the clockwise direction while the carrier gear 79 is rotated in the clockwise direction while rotating in the clockwise direction. The combined output shaft 84 is rotated by adding the hydraulic transmission force from the sun gear 78 and the transmission gear 74 power, and the engine 2 power is transmitted to the transmission gear 74 and the hydraulic transmission mechanism 57 as shown in FIG. The planetary gear mechanism 83 synthesizes and outputs, and the mission case 4 performs forward / reverse switching and PTO speed change to perform reverse, low speed forward (farm planting travel), and high speed forward (road movement travel) operations.

  Then, for example, with respect to the general input power 100, when the loss of the gear 74 is 2 and the loss of hydraulic shift is 30, the input power of the engine 2 is reduced when traveling at a low speed as shown in FIG. When the hydraulic transmission power is 50 and the hydraulic transmission power 50 returns to the pump shaft 58 and the transmission power on the gear 74 side becomes 150, the loss of the gear 74 is 3, and the hydraulic transmission mechanism 57 is lost. 15 and the output power is obtained at a rate of 82. Further, as shown in FIG. 27, when the vehicle travels at medium speed where the transmission power of the hydraulic transmission mechanism 57 is zero, the transmission power on the gear 74 side is 100, the loss of the gear 74 is 2, and the output power is 98. Obtained in proportion. Further, as shown in FIG. 28, when traveling at high speed, when the hydraulic transmission power is 40 and the transmission power on the gear 74 side is 60, the loss of the gear 74 is 1 and the loss of the hydraulic transmission mechanism 57 is 12. The power is obtained at a ratio of 87. For example, as shown in FIG. 29, by changing the angle of the hydraulic speed change operation arm 109 from −1 to 0 to 1, the motor shaft 77 rotates from −1000 to 0 to 1000 rotations. When the gear 74 side is rotated 1000 times regardless of the angle of the arm 109 as shown in FIG. 30, the composite output shaft 84 is 0 to 0 with respect to the angle of the arm 109 as shown in FIG. The gears 74 and 79 and the planetary gear mechanism 83 are composed so as to have 2000 rotations.

Further, when the entire control range of the arm 109 is set to −1 to 0 to 1, as shown in FIG. 18, the control operation on the low speed (zero speed) side and the high speed side of the arm 109 is changed to the bolt type low speed and high speed stopper 113.・ Controlled by 114, and as shown in FIG. 32, the operation range of the actual arm 109 adjustable by the stoppers 113 and 114 is set to −0.8 to 0.6, and the work of 0 to 1.4 m / s is performed. By obtaining the speed, adjustment is made by the stoppers 113 and 114 with respect to variations in output characteristics caused by assembly errors of the hydraulic transmission mechanism 57, and the positions of the arms 109, for example, -1 to -0.8 are adjusted. The speed can be made zero, and the problem that the speed does not become zero even if the arm 109 is −1 is eliminated. As shown in FIGS. 33 and 34, at a general work speed, the power sharing ratio between the hydraulic transmission mechanism 57 and the gear 74 is set to 60% or more, and the effective power on the gear 74 side with respect to the effective power of the hydraulic transmission mechanism 57. Increase the ratio of the paddy field, improve the running performance in the wet field, improve the working efficiency in the wet field, and give the escape level enough for the step of the cultivator.

  As is clear from the above, a hydraulic transmission mechanism 57 and a transmission gear 74 that transmit the driving force of the engine 2 are provided, and outputs of the hydraulic transmission mechanism 57 and the transmission gear 74 are synthesized to form a transmission output. The output of high power transmission efficiency is obtained by using the hydraulic transmission mechanism, the output of continuously variable transmission capable of zero start is obtained by using the hydraulic transmission mechanism 57, the speed adjustment according to the situation is performed by a simple shift operation, and the speed change function is improved. In addition, the handling operability is improved, and the combined output shaft 84 for synthesizing the outputs of the hydraulic transmission mechanism 57 and the transmission gear 74 by the forward or reverse output of the hydraulic transmission mechanism 57 is used in one direction. To ensure that the output torque at the time of zero start is easily secured, the speed performance is easily improved, and the output of the high power transmission efficiency of the transmission gear 74 is effectively used at the work speed, and the work on the mud road surface efficiency Achieve such improvement.

  In addition, the transmission gear 74 is formed at a reduction ratio that becomes an intermediate transmission speed between 0 and the maximum vehicle speed, and the operation of the continuously variable transmission capable of zero start is performed, but the output of the transmission gear 74 with high power transmission efficiency is constant. In order to improve the running performance and work efficiency, the ratios of the outputs of the hydraulic transmission mechanism 57 and the transmission gear 74 are substantially equal at the time of start-up, and the large work required for start-up is performed. While ensuring the output torque, the zero-start and slow-speed movement operations are smoothly performed by continuously variable speed operation, for example, ultra-low-speed traveling such as entering / exiting the loading platform of the field or transport truck or traveling over the ridge. To improve.

  In addition, during low speed or high speed travel other than when starting, continuous operation is performed in which the output ratio of the transmission gear 74 is increased with respect to the hydraulic transmission mechanism 57 and a constant speed is maintained by the output of the transmission gear 74 having high power transmission efficiency. In addition to improving the running performance and work efficiency, switching between forward and reverse rotation of the hydraulic transmission mechanism 57 at the middle of 0 to the maximum vehicle speed or more to ensure the output torque at the time of zero start, In addition, the output of the high power transmission efficiency of the transmission gear 74 is effectively utilized at the work speed, and the work efficiency on the mud road surface is improved.

  Further, when the transmission ratio of the transmission gear 74 is more than half of the whole, the operation speed is set, and continuous operation is performed to maintain a constant speed by the output of the transmission gear 74 having high power transmission efficiency, thereby improving the running performance and improving the work efficiency. At the same time, the reverse rotation output range of the hydraulic transmission mechanism 57 is made larger than the normal rotation output range between 0 and the maximum vehicle speed, improving the performance of zero start and slow running, and at the transmission speed. The output of 74 high power transmission efficiency is used effectively, and the work efficiency on the mud road surface is improved.

  Further, the driving force of the engine 2 is input to the pump shaft 58 of the hydraulic transmission mechanism 57, and the motor shaft 77 of the hydraulic transmission mechanism 57 and the transmission gear 74 connected to the pump shaft 58 are connected via the planetary gear mechanism 83. In a work vehicle that is coupled to the combined output shaft 84 and combines and outputs the hydraulic transmission and the transmission gear 74 transmission, the transmission gear 84 is rotated in one direction within the shiftable range of the hydraulic transmission mechanism 57. 74 and a planetary gear mechanism 83 are provided to achieve zero-start continuously variable transmission and high power transmission efficiency with a simple hydraulic transmission and gear composition to improve running performance and transmission operability. The rotation of the combined output shaft 84 is adjusted by the hydraulic speed change operation arm 109 of the mechanism 57, and the combined output shaft 8 is shifted from the maximum operation position on the low speed output side of the operation arm 109 to the high speed output side. The zero rotation position is set, and the output speed of the hydraulic speed change mechanism 57 or the assembly error of the speed change operation mechanism causes a shift between the lowest speed (zero speed) position of the operation arm 109 and the zero rotation position of the composite output shaft 84. Even if it occurs, the problem that the composite output shaft 84 rotates when the operation arm 109 is operated at the lowest speed is eliminated.

  Further, the output control of the hydraulic transmission mechanism 57 is performed by a one-way operation of the pedal 31 that automatically moves backward, the stepping operation of the pedal 31 causes the hydraulic transmission mechanism 57 to perform a continuously variable transmission operation, and the steering handle 14 with both hands. Operate and freely adjust the speed, for example, the steering handle 14 can be operated with one hand while the shift lever is operated with the other hand, and the conventional troublesome driving is eliminated, and the steering and shifting operability is improved. In addition, the forward / reverse switching gears 87 and 88 and the PTO output gear 93 are provided on the output side of the composite output shaft 84, and the input side of the composite output shaft 84 is combined without cutting the power with a clutch or the like. By simply turning the output shaft 84 to zero, the gears 87, 88, and 93 are switched, eliminating the need for a clutch that interrupts the output of the engine 2, and performing forward / reverse operation or PTO shifting. In addition, the gears 87, 88, 93 are brought close to each other to perform forward / reverse switching and PTO shift using the same operating mechanism, and the installation structure of the gears 87, 88, 93 is made compact and simplified. Etc.

  As apparent from the above, in a work vehicle in which a hydraulic transmission mechanism 57 and a transmission gear 74 that transmit the driving force of the engine 2 are provided, and outputs of the hydraulic transmission mechanism 57 and the transmission gear 74 are combined to form a transmission output. The combined output shaft 84 that combines the outputs of the hydraulic transmission mechanism 57 and the transmission gear 74 and rotates in one direction is rotated in one direction by the forward or reverse output of the transmission mechanism 57 and the low speed side of the hydraulic transmission mechanism 57 The combined output of the hydraulic transmission mechanism 57 and the transmission gear 74 is made zero at an output position on the higher speed side than the maximum control position of the engine, and the output torque at the time of zero start can be easily secured, facilitating slow speed performance In addition, the output of the high power transmission efficiency of the transmission gear 74 can be effectively used at the work speed, the work efficiency on the mud road surface can be easily improved, and the hydraulic transmission mechanism 57 When the hydraulic speed change operation 109 is stopped even if a shift occurs between the stop position (zero speed) of the hydraulic speed change operation and the zero rotation position of the composite output shaft 84 due to output characteristics or an assembly error of the speed change operation mechanism. The problem that the combined output shaft 84 rotates and moves forward and backward can be easily eliminated.

  Further, the driving force of the engine 2 is input to the pump shaft 58 of the hydraulic transmission mechanism 57, and the motor shaft 77 of the hydraulic transmission mechanism 57 and the transmission gear 74 connected to the pump shaft 58 are connected via the planetary gear mechanism 83. In a work vehicle that is coupled to the combined output shaft 84 and combines and outputs the hydraulic transmission and the transmission gear 74 transmission, the transmission gear 84 is rotated in one direction within the shiftable range of the hydraulic transmission mechanism 57. 74 and planetary gear mechanism 83 are provided, and a continuously variable transmission capable of zero start and high power transmission efficiency can be easily achieved with a simple hydraulic gear shift and gear composition, improving driving performance and gear shifting operability, etc. It can be easily achieved.

  Further, the rotation of the combined output shaft 84 is adjusted by the hydraulic transmission operation arm 109 of the hydraulic transmission mechanism 57. The combined output shaft 84 is shifted from the maximum operation position on the low speed output side of the operation arm 109 to the high speed output side. A zero rotation position can be set, and a deviation occurs between the minimum speed (zero speed) position of the operation arm 109 and the zero rotation position of the composite output shaft 84 with respect to the output characteristics of the hydraulic transmission mechanism 57 or the assembly error of the transmission operation mechanism. However, the problem that the combined output shaft 84 rotates when the operation arm 109 is operated at the lowest speed can be easily eliminated.

  Further, the output control of the hydraulic transmission mechanism 57 is performed by a one-way operation of the pedal 31. The stepping operation of the pedal 31 can cause the hydraulic transmission mechanism 57 to perform a stepless speed change operation. In addition, it is possible to easily adjust the speed freely. For example, the conventional troublesome operation of operating the shift lever with one hand while operating the steering handle 14 with one hand is unnecessary, and the steering and the shift operation are performed. It is possible to easily improve the performance.

1 traveling vehicle 2 engine 4 transmission case 57 hydraulic transmission mechanism 63 traveling output shaft 83 planetary gear mechanism 84 composite output shaft 85 hydraulic pump 86 hydraulic motor 87 forward gear 88 reverse gear

Claims (1)

Engine (2),
A hydraulic transmission mechanism (57) for inputting a driving force output from the engine (2);
The forward driving force output from the engine (2) and the driving force output from the hydraulic transmission mechanism (57) are input and combined, and the combined combined driving force is switched between forward driving force or backward driving force and output. A gear (87) and a reverse gear (88) mechanism,
When the hydraulic transmission mechanism (57) is shift-controlled to the highest speed position in the reverse rotation state, the traveling speed is set to be zero,
As the hydraulic speed change mechanism (57) is shift-controlled from the highest speed position in the reverse rotation state to the highest speed position in the forward rotation state via the neutral position where the output stops, the traveling speed is stepless. Configured to speed up ,
When the traveling speed is zero, the ratio of the driving force of the engine (2) and the driving force of the hydraulic transmission mechanism (57) is made equal, and when the traveling speed is other than zero, the hydraulic transmission mechanism (57 The ratio of the driving force of the engine (2) is set larger than the driving force of
Agricultural vehicle transmission.

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