JP4471791B2 - Working vehicle - Google Patents

Description

  The present invention relates to a work vehicle such as a crawler tractor.

  A link mechanism that increases or decreases the speed of the left and right traveling devices according to the operation of the steering handle is known. For example, the link mechanism disclosed in Patent Document 1 is linked to left and right HSTs (hydraulic continuously variable transmissions) that independently drive the left and right traveling devices, and travels inside the turn according to the turning operation of the steering handle. Although the aircraft is turned by decelerating the device, turning the aircraft by one-side deceleration may cause the operation of the aircraft to be extremely slow and impair turning feeling.

Therefore, as shown in Patent Document 2, it is proposed to increase the speed of the traveling device outside the turn while decelerating the traveling device inside the turn. According to such a configuration, the traveling machine body turns quickly and a good turning feeling can be obtained.
JP 2000-128013 A Japanese Patent Publication No.49-24616

  However, in the thing of patent document 2, since the speed increase amount of the turning outer side traveling apparatus is proportional to the turning operation amount of the steering handle, if the steering handle is largely turned, the centrifugal force acting on the operator increases. There is a problem that steering stability is lowered.

The present invention has been created in view of the above-described circumstances in order to solve these problems, and the invention of claim 1 is provided for the left and right traveling devices and the left and right traveling devices, respectively. A link mechanism L is provided that includes a travel motor and an HST pump provided to drive the left and right travel motors, and independently increases and decreases the speed of the left and right travel devices according to the operation of the travel speed change lever and the steering handle. In the working vehicle, the link mechanism does not increase or decrease the speed of the left and right traveling devices even when the steering handle is turned when the traveling shift lever is in the neutral position, and when the traveling shift lever is in the shift position. , in accordance with the turning operation of the steering wheel, the traveling device of the turning inner and deceleration link system for proportional deceleration, turning outside of the traveling device A working vehicle, characterized in that it comprises a speed increasing link system for accelerated state with limited speed increasing amount. If comprised in this way, since the traveling apparatus outside a turning can be accelerated while decelerating the traveling apparatus inside turning, a traveling body can be turned quickly and a turning feeling can be improved. Moreover, since the traveling device on the outside of the turn is accelerated up to a predetermined acceleration amount, the centrifugal force acting on the operator can be suppressed, and the steering stability can be improved.
The invention according to claim 2 is the work traveling vehicle according to claim 1, wherein the link mechanism changes the acceleration amount of the turning outer traveling device in accordance with the deceleration amount of the turning inner traveling device. . If comprised in this way, the speed increase amount of a turning outer side traveling apparatus can be optimized with respect to the deceleration amount of a turning inner side traveling apparatus. For example, when the deceleration amount of the turning inner traveling device is small, the aircraft is turned quickly by making the acceleration amount of the turning outer traveling device proportional, and when the deceleration amount of the turning inner traveling device is large, the turning Sudden turning can be prevented by suppressing the speed increase amount of the outer traveling device or by decelerating the turning outer traveling device.

  Next, embodiments of the present invention will be described with reference to the drawings. 1 and 2, reference numeral 1 denotes a pair of left and right crawler type traveling units mounted on the tractor T. These traveling units 1 are independently operated by HST (hydraulic continuously variable transmission). . Each HST forms a closed circuit via a hydraulic hose 4 between an HST pump 2 composed of a variable displacement hydraulic pump and a travel motor 3 composed of a fixed displacement hydraulic pump, and the rotation of the trunnion lever 5 in the HST pump 2. The output rotation of the travel motor 3 is changed according to the dynamic operation. Each trunnion lever 5 is connected to the proximal end side of the operation wire 6, and the distal end side of the operation wire 6 is connected to the travel transmission lever 8 and the round shape via a link mechanism L provided on the substrate 7. The steering handle 9 is interlocked and connected.

  As shown in FIGS. 3 to 6, the link mechanism L includes an interlocking rod 10 that moves up and down in conjunction with the operation of the traveling speed change lever 8, and an operating arm 11 that can be pivoted up and down connected to the upper end of the interlocking rod 10. And. The operating arm 11 is bifurcated so that the front end sandwiches the substrate 7 from the front and back, and the operating shaft 12 supported at the tip of the operating arm 11 inserts the slide roller 14 into the vertical guide groove 13 formed in the substrate 7. It is supported through a vertical movement. Reference numeral 15 denotes a rotating shaft of the operating arm 11.

  A pair of front and back interlocking arms 16 are connected to the front and rear ends of the operating shaft 12. Each interlocking arm 16 extends from the operating shaft 12 in an upwardly inclined manner and is connected to the base end portion of the rocking body 17 via a fulcrum shaft 18 so as to be freely rotatable. The oscillating body 17 is oscillated according to the vertical movement of the oscillating member. Reference numeral 19 denotes a rotation shaft of the rocking body 17.

  An arcuate guide groove 20 is formed in the oscillating body 17 in the longitudinal direction, and a base end portion of an operation rod 21 is engaged with the guide groove 20 via a roller 22. One end of a bell crank 23 is connected to the tip of the operation rod 21 via a rotating shaft 24, and the operation wire 6 of the HST is connected to the other end of the bell crank 23. That is, when the travel shift lever 8 is operated, the left and right operating wires 6 are moved in the same direction via the interlocking rod 10, the operating arm 11, the operating shaft 12, the interlocking arm 16, the rocking body 17, the operating rod 21, and the bell crank 23. A travel shift link system 25 is configured to push and pull and shift the left and right travel sections 1 simultaneously. Reference numeral 26 denotes a rotating shaft of the bell crank 23.

  Next, the deceleration link system L1 that proportionally decelerates the traveling motor 3 inside the turn according to the turning operation of the steering handle 9 will be described. The steering handle 9 is connected to a small gear 30 via a universal joint (not shown) and a bevel gear 29. A sector gear 31 that meshes with the small gear 30 and swings left and right is pivotally supported on the substrate 7, and the rear thereof is covered with a holder 32. On the front and back surfaces of the substrate 7, there is provided a turning link 33 that can be turned up and down. A roller shaft 34 provided in the middle of the substrate 7 is supported on the upper right edge and the upper left edge of the sector gear 31, respectively. Reference numeral 35 denotes an arc-shaped insertion hole through which the roller shaft 34 penetrates the front and back of the substrate 7, and 36 denotes a pivot point of the pivot link 33.

  The distal end portion of the swivel link 33 and the base end portion of the operating rod 21, that is, the position of the roller 22 that engages the rocking body 17 are interlocked and connected via a connecting plate 37, and the steering handle 9 is in the neutral position. In some cases, the tip of the swivel link 33 matches the axis of the pivot shaft 19 of the rocking body 17. When the steering handle 9 is steered, the sector gear 31 that swings in conjunction with the steering handle 9 pushes up one of the roller shafts 34, and the swing link 33 that moves upward pulls up the operating rod 21 to rotate it. The engaging position of the operating rod 21 engaged with the guide groove 20 is changed along the guide groove 20.

  When the travel shift lever 8 is in the neutral position and the operating shaft 12 is positioned at the center of the guide groove 13, the guide groove 20 of the oscillating body 17 is a circle having a radius of curvature R around the rotation shaft 24 of the operating rod 21. It has an arc shape, and this radius of curvature R is equal to the length from the rotation shaft 24 of the operation rod 21 to the roller 22. For this reason, when the traveling speed change lever 8 is in the neutral position, even if the engagement position of one of the operating rods 21 is changed along the guide groove 20 by operating the steering handle 9, the operating rod 21 moves the rotating shaft 24. It only turns around the center. On the other hand, when the oscillating body 17 is rotated by the speed change operation of the traveling speed change lever 8, the center position of the curvature of the guide groove 20 changes. Therefore, the operation rod 21 whose engagement position is changed by the operation of the steering handle 9 is rotated. The bell crank 23 is rotated by moving in the longitudinal direction without rotating about the moving shaft 24. As a result, the traveling motor 3 (the trunnion lever 5) inside the turn is decelerated through the operation wire 6, and a deceleration turn is performed. When the steering amount of the steering handle 9 exceeds a predetermined amount, the traveling motor 3 on the inner side of the turn reverses through the neutral position and a spin turn is performed. Reference numeral 38 denotes a spring mechanism for urging the swing link 33, and reference numeral 39 denotes a stopper for restricting the swing range of the sector gear 31.

  Next, the speed increasing link system L2 for increasing the speed of the traveling motor 3 on the outer side of the turning up to a predetermined speed increasing amount according to the turning operation of the steering handle 9 will be described. As shown in FIGS. 7 and 8, the speed increasing link system L <b> 2 is configured on the front side of the substrate 7, and includes a drive gear 40, a driven gear 41, and a speed increasing cam 42. The drive gear 40 is provided on the support shaft 31 a of the sector gear 31 and is rotated integrally with the sector gear 31. The driven gear 41 is provided below the drive gear 40 and meshed with the drive gear 40. The speed increasing cam 42 is integrally provided inside the driven gear 41 and is rotated together with the driven gear 41. That is, when the sector gear 31 is rotated according to the turning operation of the steering handle 9, the speed increasing cam 42 is rotated in the opposite direction.

  When the steering handle 9 is steered, the sector gear 31 that swings in conjunction with this raises one roller shaft 34 and lowers the other roller shaft 34. When the roller shaft 34 is lowered, the traveling motor 3 (the trunnion lever 5) on the outer side of the turn is accelerated through the operation wire 6 based on the action opposite to that of the deceleration link system L1 described above. At this time, the speed increasing cam 42 is in contact with the other roller shaft 34 from below to limit the lowering amount of the roller shaft 34 (speed increasing amount on the outer side of the turning) and the operation amount of the steering handle 9 (turning) The lowering amount of the roller shaft 34 is changed according to the inner deceleration amount. Thus, while the traveling unit 1 on the inside of the turn is proportionally decelerated, the traveling unit 1 on the outside of the turn can be accelerated up to a predetermined acceleration amount, and the acceleration amount on the outside of the turning can be reduced to the deceleration amount on the inside of the turning. It becomes possible to change according to.

  FIG. 9 is an operation explanatory diagram of the speed increasing link system L2 when the traveling speed change lever 8 is in the neutral position, and FIG. 10 is an operation explanatory view of the speed increasing link system L2 when the travel speed shifting lever 8 is in the forward movement position. As shown in these figures, when the traveling speed change lever 8 is in the forward movement position and the steering handle 9 is in the neutral position, the bell crank 23 is rotated to the acceleration side by a predetermined angle α. When the steering handle 9 is turned, the bell crank 23 on the outside of the turn is turned to the speed increasing side. The amount of rotation (β−α) of the bell crank 23 accompanying the turning operation can be arbitrarily set based on the cam shape of the speed increasing cam 42, thereby enabling a desired speed increasing pattern to appear. become. For example, as shown in FIG. 11, in the deceleration turning region (turning inner deceleration region), the traveling unit 1 outside the turning is accelerated to improve turning performance, while in the pivot turning region (turning inner stop region), the turning outside. It is possible to stop the increase in speed so as not to impair the feeling of pivoting. In addition, as shown in FIG. 12, if the traveling unit 1 outside the turn is decelerated in the spin turning region (turning inside reverse region), there is an advantage that rapid spin turning can be prevented.

  Next, the speed increase limiting mechanism 43 that limits the speed increase amount of the turning outer side travel unit 1 when the travel shift lever 8 is in the high speed range will be described. The speed increase limiting mechanism 43 includes a restriction cam 44 that is rotatably provided inside the speed increase cam 42 and a connection link 45 that is interposed between the restriction cam 44 and the operating arm 11. Accordingly, the regulating cam 44 is rotated in accordance with the rotation of the operating arm 11 accompanying the shift operation of the travel shift lever 8. The regulating cam 44 shown in FIG. 13 does not interfere with the roller shaft 34 even if the steering handle 9 is turned when the traveling speed change lever 8 is in the low speed range, but it moves down when the traveling speed change lever 8 is in the high speed range. The cam shape is set so as to interfere with the shaft 34 and limit the speed increase amount of the turning outer traveling unit 1. Incidentally, the restriction cam 44 shown in FIG. 13 is formed in an isosceles triangle shape, and when the traveling speed change lever 8 is in the high speed region, the lowering of the roller shaft 34 is restricted at the two top portions.

  There is no restriction | limiting in particular in the shape of the control cam 44, The acceleration amount of the turning outer side traveling part 1 can be restrict | limited arbitrarily. For example, as shown in FIG. 14, the shape of the restriction cam 44 may be set so that the speed increase limiting ratio of the turning outer side travel unit 1 changes according to the speed change range of the travel speed change lever 8. If it does in this way, since the amount of acceleration of the turning outside traveling part 1 decreases as the traveling speed increases, it becomes possible to realize the optimum amount of acceleration according to the shift range.

  The tractor T of the present embodiment configured as described above is provided with a link mechanism L that increases and decreases the speed of the left and right traveling units 1 in accordance with the operation of the steering handle 9. The vehicle is provided with a deceleration link system L1 that proportionally decelerates the traveling unit 1 on the inside of the turn according to an operation, and an acceleration link system L2 that increases the speed of the traveling unit 1 on the outside of the turn up to a predetermined acceleration amount. While the inner traveling unit 1 is decelerated, the traveling unit 1 outside the turn can be accelerated. In addition, since the traveling unit 1 outside the turn is accelerated up to a predetermined acceleration amount, the centrifugal force acting on the operator can be suppressed, and the steering stability can be improved.

  Further, since the link mechanism L changes the speed increase amount of the turning outside traveling unit 1 in accordance with the deceleration amount of the turning inside traveling unit 1, the speed increasing amount of the turning outside traveling unit 1 is changed to that of the turning inside traveling unit 1. It is possible to optimize the deceleration amount. For example, when the amount of deceleration of the turning inner traveling unit 1 is small, when the speed increase amount of the turning outer traveling unit 1 is made proportional, the aircraft is turned quickly and the amount of deceleration of the turning inner traveling unit 1 is large. Can prevent sudden turning by suppressing the amount of acceleration of the turning outer traveling unit 1 or by decelerating the turning outer running unit.

  Further, the link mechanism L is linked to the travel speed change lever 8, and when the travel speed change lever 8 is in a high speed range, the link mechanism L restricts the speed increase amount of the turning outside travel portion 1, thereby ensuring the centrifugal force acting on the operator. The steering stability can be further improved.

  Further, since the link mechanism L changes the speed increase limiting ratio of the outer turning traveling unit 1 in accordance with the speed change range of the traveling shift lever 8, the acceleration amount of the outer turning traveling unit 1 is optimal for the traveling speed. Can be For example, when the vehicle is traveling at a low speed, the speed increase amount of the outside turning unit 1 is increased to turn the aircraft quickly, and at the time of high speed operation, the amount of acceleration of the outside turning unit 1 is decreased to make a sharp turn. Can be prevented.

It is a side view of a tractor. It is a schematic perspective view which shows the traveling operation system of a tractor. It is a front view (rear view) of a link mechanism. It is a rear view (front view) of a link mechanism. It is a side view of a link mechanism. It is a principal part side view of a link mechanism. It is a principal part front view which shows an acceleration link system. It is a principal part expanded sectional view which shows a speed-increasing link system. It is operation | movement explanatory drawing of the speed increasing link system at the time of driving | running | working transmission lever neutral. It is operation | movement explanatory drawing of the speed-increasing link system at the time of driving | running | working transmission lever advance. It is a graph which shows the example of the speed increasing pattern by a speed increasing link system. It is a graph which shows the other example of the acceleration pattern by an acceleration link type | system | group. It is operation | movement explanatory drawing of a speed increase limitation mechanism. It is a graph which shows the example of the speed limit pattern by a speed limit mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Traveling part 2 HST pump 3 Traveling motor 6 Operation wire 7 Board | substrate 8 Traveling speed shift lever 9 Steering handle 11 Actuating arm 16 Interlocking arm 17 Oscillator 21 Operation rod 23 Bell crank 25 Traveling speed link system 31 Sector gear 33 Turning link 34 Roller shaft 40 Drive gear 41 Driven gear 42 Speed increasing cam 43 Speed increasing limiting mechanism 44 Restricting cam 45 Connecting link L Link mechanism L1 Deceleration link system L2 Speed increasing link system

Claims (2)

A left and right traveling device, a traveling motor provided in each of the left and right traveling devices, and an HST pump provided to drive the left and right traveling motors, respectively , In a working vehicle provided with a link mechanism L for independently increasing / decreasing the speed of each traveling device, the link mechanism is configured such that when the traveling speed change lever is in the neutral position, the left and right traveling devices are operated even if the steering handle is turned. There is no acceleration / deceleration, and when the travel speed change lever is in the shift position, the speed reduction link system that proportionally decelerates the travel device on the inside of the turn according to the turning operation of the steering handle and the travel device on the outside of the turn are limited to the speed increase amount. A work traveling vehicle comprising a speed increasing link system for speeding up in a certain state .   The working vehicle according to claim 1, wherein the link mechanism changes an acceleration amount of the turning outer traveling device according to a deceleration amount of the turning inner traveling device.

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