JP3897780B2 - Work vehicle - Google Patents

Description

  The present invention relates to a work vehicle.

Conventionally, there are work vehicles in which the driving drive speed of the left and right traveling devices is varied to make the aircraft turn, and for changing the traveling speed, the gear ratio can be changed in a forward and reverse stepless manner with a shift lever etc. For continuously turning using a continuously variable transmission, use a continuously variable transmission for turning that can change the gear ratio between forward and reverse continuously with a steering wheel, etc., and output the output of these continuously variable transmissions with a left and right planetary gear mechanism. The left and right traveling units are individually driven by combining (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 9-216570

  In the above-described work vehicle, when the vehicle is traveling backward, the relationship between the direction of operation of the steering wheel or the like and the turning direction of the fuselage is opposite to that during the forward movement and is different from that of the wheel type work vehicle. was difficult.

  Further, since two expensive continuously variable transmissions are used, there is a problem that the manufacturing cost becomes high.

Therefore, in the present invention, the left and right planetary gear mechanisms are interlocked and connected to the engine through the straight power transmission system and the turning power transmission system, and the rotational speeds of the straight power transmission system and the turning power transmission system are connected by the left and right planetary gear mechanisms. The left and right traveling devices are individually driven at the combined rotational speed , and the forward / reverse clutch that branches and transmits to both the power transmission systems by exclusively selecting the power from the engine, in work vehicle which is interposed between the power transmission system and the turning power transmission system, the straight drive train while constituting only a gear type transmission mechanism, an output rotation by operation of the steering wheel in the turning power transmission system A continuously variable transmission for turning that can change the speed is provided , and the entire straight power transmission system and the turning power transmission system are configured to have a single continuously variable transmission for turning to transmit the turning power transmission. system Turning continuously variable transmission, the transmission Ke accommodating the straight drive train and the turning power transmission system - is to provide a work vehicle, characterized in that mounted arranged on the outer wall portion of the scan.

  In the present invention, a forward / reverse clutch for exclusively selecting the power from the engine is interposed between the engine and the straight power transmission system and the turning power transmission system. The wheel operation direction and the turning direction of the fuselage can be maintained in a fixed relationship, the steering wheel can be operated in the same way as a wheel type work vehicle, and the operation during turning can be facilitated. It is possible to ensure good operational safety.

Moreover, straight power transmission system while constituting only a gear type transmission mechanism, the turning power transmission system provided with a pivot for a continuously variable transmission that is capable of changing the output rotation speed by operation of the steering wheel, straight power transmission And the turning power transmission system are configured to include a single turning continuously variable transmission, and the turning continuously variable transmission of the turning power transmission system includes a straight power transmission system and a turning power transmission system. Since it is mounted on the outer wall of the mission case that houses the vehicle, only one expensive continuously variable transmission is required, which contributes to a reduction in manufacturing costs.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a work vehicle A according to the present invention. The tractor A includes a driving unit 3, a motor unit 4 and the like above a traveling unit 2 equipped with crawler-type left and right traveling devices 1a and 1b. The body frame 5 is mounted, and a rotary tiller 6 as an agricultural machine is connected to the rear end of the body frame 5.

  As shown in FIGS. 1 to 3, the traveling unit 2 is arranged by extending a pair of left and right vertical frames 7a and 7b in the front-rear direction, and the front and rear parts of the left and right vertical frames 7a and 7b are arranged with a lower opening. The front and rear portal frames 8a and 8b are connected to form a traveling unit frame 9. The left and right front idler wheels 11a and 11b are pivotally supported at the front ends of the left and right vertical frames 7a and 7b via the tensioners 10, respectively. The left and right rear idler wheels 12a and 12b are pivotally supported on the rear ends of the left and right vertical frames 7a and 7b, respectively, and the plurality of rolling wheels 13 are pivotally supported on the lower surfaces of the left and right vertical frames 7a and 7b. Left and right sprockets 14a and 14b are pivotally supported above the vertical frames 7a and 7b, respectively, and left and right crawlers 15a and 15b are respectively arranged on the outer circumferences of the front and rear idle wheels 11 and 12, the plurality of rolling wheels 13 and the left and right sprockets 14a and 14b. The left and right traveling devices 1a and 1b are configured.

  In particular, in this embodiment, the front and rear portal frames 8a and 8b are used to connect the left and right vertical frames 7a and 7b, and the minimum ground clearance is increased to improve the running performance on the field. Since the working machine is connected to the rear of A, the front idler wheel 11 is mounted at a higher position than the foremost rolling wheel 13 and the angle of attack of about 21 degrees is set at the front end of the left and right crawlers 15a and 15b. α is formed to improve driving performance when oversteps such as kites.

  As shown in FIGS. 1 to 3, the vehicle body frame 5 is constructed by extending left and right side members 16a and 16b extending in the front-rear direction on the upper surfaces of the front and rear portal frames 8a and 8b, and the front and rear ends of the left and right side members 16a and 16b. The front and rear struts 17a and 17b are respectively erected at the center, and the round pipe is refracted to form an upper frame 18 that is substantially U-shaped in the rear opening in a plan view and inclined to the front low and rear height in a side view. The upper frame 18 is installed on the upper ends of the front and rear support columns 17a and 17b to form a frame-shaped body frame 5.

  A steering wheel 21 is erected at the front end of the vehicle body frame 5, and a seat 22 is arranged behind the steering wheel 21 at a predetermined interval to constitute the driving unit 3. 23, and a transmission 24 is arranged below the engine 23 to constitute the prime mover unit 4. The left and right sprockets 14a, 14b are located outside the left and right drive shafts 25a, 25b protruding from the transmission 24 to the left and right sides. Each end is fitted. In the figure, 26 is a vehicle body cover, 27 is a battery, 28 is a fuel tank, and 29 is a shift lever.

  In particular, the seat 22 where the driver sits and the weight increases significantly, and the engine 23 and the transmission 24, which are heavy in weight, are placed on the inner side of the ground contact surface WB, that is, with the foremost rolling wheel 13 and the rear idler of the traveling unit 2. Arranged above the wheel 12, the front and rear weight balance of the work vehicle A is improved, and the stability of the vehicle body against the front and rear inclination is enhanced.

  In addition, heavy objects such as the battery 27 and the fuel tank 28 are also arranged above the foremost rolling wheel 13 and the rear idler wheel 12 to further improve the stability of the vehicle body against the forward and backward inclination.

  The rotary tiller 6 is connected via a three-point link mechanism 30 provided at the rear part of the vehicle body frame 5, and the rotary tiller is driven by a lifting hydraulic cylinder 32 interposed between the vehicle body frame 5 and the top link 31. The power from the engine 23 is transmitted to the rotary tiller 35 via the work machine drive shaft 33 and the belt transmission mechanism 34.

  FIG. 4 shows another embodiment in which the operating portion 3 and the engine 23 are disposed in the same position as described above, but the transmission 24 is disposed below the seat 22. It differs from the previous embodiment in that it is disposed behind the left and right vertical frames 7a, 7b to pivotally support the rear idler wheel 12 and pivotally support the front idler wheel 11 via a bracket 36.

  In this embodiment as well, heavy objects such as the seat 22, the engine 23, the transmission 24, the battery 27, and the fuel tank 28 are disposed on the inner upper side of the ground contact surface WB to enhance stability.

5 to 6 and FIGS. 8 to 9 show the first embodiment of the transmission 24. The first to ninth shafts 41 to 49 are supported in parallel inside the transmission case 40, and the first shaft The input side of the forward clutch 50a is fitted in the middle portion of 41, and the end of the first shaft 41 is inserted through the first meshing gear 51 and the forward and backward clutches 50a, 50b loosely fitted in the middle of the second shaft 42. An input side and an elevating hydraulic pump 52 are linked to each other, and an output side of the forward clutch 50a and a second shaft 42 which is an output side of the reverse clutch 50b are connected to a third shaft 43 via a second meshing gear 53. By interlocking connection, the power transmission of the forward / reverse clutches 50a, 50b can be exclusively selected to enable forward / reverse switching in the driving direction.

  The third shaft 43 is linked to an input shaft 55 of a turning continuously variable transmission (hereinafter referred to as HST) 54 and is connected to an input shaft 55 of a main transmission unit 57 via a third meshing gear 56. 44, and the above-mentioned turning continuously variable transmission 54 is arranged on the lower side of the forward / reverse clutches 50a, 50b, and is linked to the switching operation of the forward / reverse clutches 50a, 50b. The rotation direction of the input shaft of the transmission 54 is switched.

  A slider 60 integrally formed with dogs 58, 58 at both ends and a second speed driving gear 59 at the center is fitted to the fourth shaft 44 so as to be axially slidable and non-rotatable. Between the fourth shaft 44 and the fifth shaft 45, which is the output shaft of the main transmission unit 57, first and third speed meshing gears 61, 62 of constant meshing type are interposed, and slidingly meshed with the fifth shaft 45. A second speed passive gear 63 of the type is fitted and the output rotational speed of the main transmission 57 can be switched in three stages by sliding the slider 60.

  A sub-transmission unit 64 is connected to the main transmission unit 57 in series. The sub-transmission unit 64 is interposed between the fifth shaft 45 and the sixth shaft 46 that is the output shaft of the sub-transmission unit 64. The output rotational speed of the subtransmission unit 64 is sandwiched between the neutral position by the sliding of the slider 67 that is inserted in the sixth shaft 46 so as to be axially slidable and non-rotatable. The speed can be changed in two stages, high and low.

  In this way, the forward / reverse clutches 50a, 50b, the three-speed shift main transmission 57 and the two-speed shift sub-transmission 64 are linked in series. Six stages of shifting operations are possible.

  The sixth shaft 46 is interlocked and connected to the seventh shaft 47 via a chain interlocking mechanism 68, and left and right sun gears 69 a and 69 b fitted to the left and right ends of the seventh shaft 47, respectively, Left and right cages 70a and 70b connected to left and right drive shafts 25a and 25b arranged with the same axis line, a plurality of left and right planetary gears 71a and 71b respectively attached to the left and right cages 70a and 70b, and the output shaft of the HST 54 The left and right planetary gear mechanisms 74a and 74b are composed of the left and right ring gears 73a and 73b that are linked to 72, and the left and right planetary gear mechanisms 74a and 74b are mechanical gears composed of the gear-type transmission, the meshing gear, etc. The rotational power transmitted to the left and right sun gears 69a and 69b by the straight power transmission system M composed of a type transmission mechanism and the rotational power transmitted to the left and right ring gears 73a and 73b from the HST 54 of the turning power transmission system H described later are combined. , These combined rotational power is transferred to the left and right planetary gears 71a Over di 70a, via the 70b, the left and right drive shafts 25a, left and right sprockets 14a which is fitted to 25b, so that transmit individually 14b.

  The output shaft 72 of the HST 54 is provided with a forward / reverse rotation division mechanism 75 that transmits the rotational speed of the output shaft 72 to the left and right ring gears 73a and 73b in a complementary manner. The eighth shaft 48 is linked to the output shaft 72 of the HST 54 via the reduction gear group 76, and the eighth shaft 48 is linked to the ninth shaft 49 via the first intermediate meshing gear 77. Left and right output gears 78a and 78b are fitted to the left and right ends of 49, respectively, and the left output gear 78a and the left ring gear 73a are interlocked and connected via two idle gears 79 and 79 arranged in series. The output gear 78b and the right ring gear 73b are interlocked and connected via one idle gear 79, and the absolute value of the rotational speed is the same, but the left ring gear 73a rotates in the same direction as the ninth shaft 49, The ring gear 73b is transmitted with rotation in the direction opposite to that of the ninth shaft 49.

Then, one end of the first shaft 41 as an input shaft of the transmission 24 is projected from the side surface of the transmission case 40, and the projecting end and the engine output shaft 80 are coupled to each other via the belt mechanism 34, while the steering wheel 21 is interlocked and connected to the speed change operation unit 104 (see FIG. 7) of the HST 54, and the speed ratio of the HST 54 is changed in a forward and reverse stepless manner according to the turning operation of the steering wheel 21. 5, 81 is a rotary shaft, 82 is a tilling claw, 83 and 84 are chain transmission mechanisms, 85a and 85b are shifters of the forward / reverse clutches 50a and 50b, 86 is a shifter of the main transmission 57, 87 is a shifter of the sub-transmission unit 64, and 88 is a meshing bevel gear for taking out power to the outside.

  With this configuration, the power from the engine 23 is shifted in six stages in the front and rear and transmitted to the left and right traveling devices 1a and 1b of the traveling unit, and the output rotation speed of the HST 54 is changed according to the operation angle of the steering wheel 21, It is possible to turn the work vehicle A in the direction in which the driving speed becomes slower by changing the driving speed of the traveling devices 1a and 1b.

  In particular, in this embodiment, since the input shaft 55 of the HST 54 is interlocked with the output side of the forward / reverse clutch 50b, the HST 54 is switched simultaneously with the switching of the forward / rearward clutches 50a and 50b without operating the steering wheel 21. The output rotation direction of the vehicle is switched, the operation direction of the steering wheel 21 and the turning direction of the work vehicle A maintain a certain relationship, and the turning operation is performed with a feeling almost similar to the steering operation of the wheel type vehicle. Can do.

FIG. 10 shows a second embodiment of the transmission 24. In this embodiment, the input shaft 55 of the HST 54 is interlocked with the engine 23 without using the forward / reverse clutches 50a, 50b. Instead, a forward / reverse switching mechanism 90 is provided between the eighth shaft 48 and the ninth shaft 49 to switch between the forward / reverse switching mechanism 90 and the forward / reverse clutches 50a, 50b. The operation direction of the steering wheel 21 and the turning direction of the work vehicle A are maintained in a fixed relationship by switching the rotation direction of the power transmitted to the left and right ring gears 73a and 73b in conjunction with each other.

  That is, the first shaft 41 and the input shaft 55 of the HST 54 are interlocked and connected via the first meshing gear 91, and left and right driving gears 92a and 92b are fitted to the left and right sides of the eighth shaft 48, respectively. The gear 92a and the left passive gear 93a loosely fitted to the ninth shaft 49 are interlocked and connected via two idle gears 79 and 79 arranged in series, and loosely fitted to the right driving gear 92b and the ninth shaft 49. The right passive gear 93b is interlocked with one idle gear 79, and a slider 94 having dogs 58 and 58 formed on the left and right ends respectively on the ninth shaft 49 is slidable in the axial direction. The outer part is immovably fitted, and the rotational direction of the power transmitted to the left and right sun gears 69a and 69b is switched by the sliding of the slider 94. The rest of the configuration is substantially the same as in the first embodiment.

FIG. 11 shows the relationship between the operating angle of the steering wheel 21, that is, the output rotation speed of the HST 54, and the driving speeds of the left and right traveling apparatuses 1a and 1b. The horizontal axis indicates the output rotation speed of HST54. Each solid line indicates the driving speed at the first speed to the sixth speed of one crawler type traveling device from the bottom, and each broken line indicates the other crawler type from the bottom. The driving speed of the traveling device at the first speed to the sixth speed is shown, and in the lower hatched portion h, the driving speed of the crawler type traveling device that has become slower transitions from zero to the direction opposite to the traveling speed of the aircraft. Further, the size of the arrow in the lower frame indicates the driving speed of the left and right traveling devices 1a and 1b.

  In this embodiment, even if the relationship between the operation angle of the steering wheel 21 and the gear ratio of the HST 54 is limited and the steering wheel 21 is rotated to the maximum operation angle θ1, the third speed to the sixth speed In traveling, the sign of the driving drive speed vector of the left traveling apparatus 1a is the same as the sign of the traveling drive speed vector of the right traveling apparatus 1b, and no pivot turn or spin turn is possible, and only normal turning is possible. In the second speed traveling, the slower crawler traveling device becomes zero, and the pivot tanning is possible but the spin turn cannot be performed. In the first speed traveling, the traveling driving speed of the left traveling device 1a is The sign of the vector and the sign of the vector of the traveling drive speed of the right traveling device 1b can be made different to enable pivot tanning and spin turn, and the steering wheel 21 can be turned into an angle that is about 1/2 of the maximum operating angle θ1. In the case of the second to sixth speed travel, the sign of the travel drive speed vector of the left travel apparatus 1a and the sign of the travel drive speed vector of the right travel apparatus 1b are the same in the second to sixth speed traveling. Therefore, only normal turning is possible, and in the first speed traveling, the slower crawler type traveling device becomes zero and the pivot tanning is possible, but the spin turn cannot be performed.

  Thus, at the time of high speed traveling from the third speed to the sixth speed, the positive and negative turning driving of the turning power transmission system H for the left and right traveling devices 1a and 1b when the steering wheel 21 is rotated to the maximum extent. Since the travel drive speed vector of the straight power transmission system M is set to be larger than the maximum speed vector, sudden turning is prevented, safety during turning is ensured, and the first for work etc. When traveling at a low speed in the first or second speed, the work efficiency can be improved by performing a pivot turn or a spin turn.

FIG. 7 shows a hydraulic circuit . The discharge side of the lifting hydraulic pump 52 is connected to the hydraulic circuit inside the HST 54, and the lifting hydraulic pump 52 is also used as a charge pump for the HST 54. In the figure, 100 is a hydraulic valve for raising and lowering control, 101 is a relief valve, 102 and 103 are hydraulic pumps and hydraulic motors in the HST 54, 104 is a speed change operation unit, 105 is a check valve, and 106 is a throttle valve.

The side view of the work vehicle which concerns on this invention. The top view of a driving | running | working part. The front view of a driving | running | working part. The side view of another Example working vehicle. Power transmission system diagram (first embodiment). 1 is a cross-sectional side view of a transmission (first embodiment). Hydraulic circuit diagram . FIG. 3 is a cross-sectional plan view of the transmission showing the straight power transmission system (first embodiment) . 1 is a cross-sectional plan view of a transmission showing a turning power transmission system (first embodiment) . Power transmission system diagram (second embodiment) . The graph which shows the relationship between the drive speed of a left-right traveling apparatus, and HST output rotation speed .

Explanation of symbols

A Work vehicle H Turning power transmission system M Straight power transmission system
1a, 1b Left and right traveling device
21 Steering wheel
23 Engine
50a, 50b Forward / reverse clutch
54 Continuously variable transmission for turning
55 Input shaft
74a, 74b Left and right planetary gear mechanism
75 Forward / reverse rotation split mechanism

Claims (1)

The left and right planetary gear mechanism is connected to the engine (23) through a straight power transmission system (M) and a turning power transmission system (H).
(74a, 74b) are linked together, and the rotational speeds of the straight power transmission system (M) and the turning power transmission system (H) are synthesized by the left and right planetary gear mechanisms (74a, 74b) to obtain a combined rotational speed. The left and right traveling devices (1a, 1b) are configured to be driven individually, and the forward / reverse clutch is selected by exclusively selecting the power from the engine (23) and branching to both the power transmission systems (M) and (H). (50a, 50b) In a work vehicle in which the engine (23) is interposed between the straight power transmission system (M) and the turning power transmission system (H), the straight power transmission system (M) is a gear-type shift. while constituting only by a mechanism, the turning power transmission system (H) is a steering wheel by the operation of (21) can change the output speed and the turning continuously variable transmission (54) is provided, straight power transmission The system (M) and the turning power transmission system (H) are configured with a single turning continuously variable transmission (54), and the turning power transmission system (H) is continuously variable for turning. The speed machine (54) is mounted on the outer wall portion of the mission case (40) that houses the straight power transmission system (M) and the turning power transmission system (H) .

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