JP2004196300A - Travel transmission structure of working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly carry out a shift from straight travel to turning travel and from turning travel to straight travel without causing any great shock. <P>SOLUTION: The working vehicle is provided with a differential switching device 16 switching the differential device 6 between non differential condition and differential condition. In the non differential condition, traveling power is transmitted to a crawler traveling device 8 on the left and right sides via a differential device 6, and the machine body is moved straight by preventing the differential of the crawler traveling device 8 on the left and right sides. In the differential condition, turning of the machine body is enabled by allowing the differential of the crawler traveling device 8 on the left and right sides. A frictional brake 15 for steering is interposed in the working vehicle. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a traveling transmission structure of a working machine traveling by operation of left and right crawler traveling devices.

Conventionally, as a traveling power transmission structure of a working machine as described above, there is a traveling power transmission structure configured to transmit traveling power to left and right crawler traveling devices via left and right clutches and brakes. In this case, by setting both the left and right clutches and brakes to the transmission state, a straight traveling state in which the left and right crawler-type traveling devices are driven at a constant speed appears, and one clutch / brake is set to the transmission state and the other clutch / brake is set to the non-drive state. By setting the transmission state, a slow turning state in which only one crawler type traveling apparatus is driven and the other crawler type traveling apparatus is driven appears, and one clutch / brake is in the transmission state and the other clutch / brake is in the braking state. As a result, a sharp turning state in which only one crawler traveling device is driven and the other crawler traveling device is braked appears ( If example see Patent Document 1).
JP-A-10-37903

  However, according to the above prior art, since the crawler type traveling device has a large contact area with the ground and a large adhesion (frictional force) to the ground, the working site has a large traveling resistance, for example, in a field with soft ground. When there is, one clutch / brake is switched from the transmission state to the non-transmission state in order to show a gentle turning state in which the left and right crawler type traveling devices are driven at a constant speed from the straight traveling state and the one crawler type traveling device is driven. Immediately after that, the crawler type traveling device corresponding to one of the clutches and brakes hardly follows the brakes stopped by the brakes due to its adhesion force or running resistance, that is, a sudden turning state appears There was a case where a large shock was generated in a state of being shocked.

  Conversely, when one of the clutches and brakes is switched from the non-transmission state to the transmission state in order to bring the straight-running state from the turning state, the crawler-type traveling device corresponding to the one clutch / brake causes the adhesive force and In some cases, high-speed driving is suddenly performed from a state where braking is stopped by a brake due to running resistance or the like, and thus a large shock may be generated even when shifting from turning to straight running.

  An object of the present invention is to make it possible to smoothly perform a transition from straight running to turning running and a transition from turning running to straight running without generating a large shock.

  As means for solving the above problems, in the present invention, power for traveling is transmitted to left and right crawler traveling devices via a differential device, and the differential device is transmitted to the left and right crawler traveling devices. Providing a differential switching device for switching between a non-differential state in which the aircraft travels straight by blocking the differential, and a differential state in which the left and right crawler-type traveling devices allow the aircraft to turn while allowing the differential, Equipped with a friction brake for steering.

  According to this configuration, when the differential device is switched to the non-differential state by the differential switching device, the left and right crawler-type traveling devices are prevented from being differentially driven. State can be expressed, and when the differential device is switched to the differential state by the differential switching device, a turnable state in which the left and right crawler type traveling devices are driven in a state in which the differential is allowed is generated. In this state, when a braking force is applied to one crawler type traveling device by the friction brake, one crawler type traveling device is decelerated by the action of the differential device, and the other crawler type traveling device is accelerated. As a result, a turning state in which the left and right crawler-type traveling devices are driven at unequal speed can be realized. In this turning state, the braking force of the friction brake is adjusted, so that the left and right crawler-type traveling devices can be driven. From gentle turning state to non-uniform driving in a state close to a constant speed, until suddenly turning state to completely stop braking the one crawler traveling apparatus can be revealing stepless.

  In other words, the turning state does not appear by cutting off the transmission to one of the crawler-type traveling devices as in the prior art described above, but the left and right crawler-type traveling devices are made unequal by the action of the differential device and the friction brake. Since the turning state is made to appear by driving at high speed, even when the work site has a large running resistance, for example, in a weak ground field, when the turning state is made to appear from the straight traveling state, When the crawler-type traveling device is suddenly stopped by the brakes due to its adhesive force, running resistance, and the like, and when it comes out of the turning state to the straight traveling state, one of the crawler-type traveling devices Does not cause the inconvenience of suddenly driving at a high speed from a state where the brake is stopped by the brake due to its adhesive force and running resistance. Comprising a transition and the transition from cornering to straight running as smoothly performed without causing a great shock.

  Further, in the above-described conventional technique employing a clutch / brake, the transmission state of one crawler traveling apparatus is maintained irrespective of a change in braking force on the other crawler traveling apparatus switched to the non-transmission state. While the driving speed is constant, the present invention employs a differential device, so that when one of the crawler-type traveling devices is decelerated by the friction brake, the other crawler-type traveling device is increased in speed. As a result, the speed difference between the left and right crawler traveling devices can be made larger than in the case where clutches and brakes are employed, and the aircraft can be turned with a smaller turning radius.

  Furthermore, by adopting the differential device, the left and right crawler-type traveling devices can be arranged on the same axis as the differential device and the left and right friction brakes. The size of the transmission case can be reduced, and the size of the aircraft can also be reduced.

  Therefore, the transition from straight running to turning running and the transition from turning running to straight running can be performed smoothly without generating a large shock, and the turning performance can be improved and the transmission case and the body can be downsized. Was.

  As one of means for making the present invention more preferable, the differential switching device is configured to show a non-differential state of the differential device by engagement of a pawl clutch, and to release the engagement by disengagement of the pawl clutch. The differential state of the differential device appears, and in the differential state, the differential between the left and right crawler-type traveling devices can be suppressed by joining the friction clutch.

  According to this configuration, for example, immediately after the differential device is switched from the non-differential state to the differential state, or immediately before the differential device is switched from the differential state to the non-differential state, the friction clutch is connected and the difference between the left and right crawler-type traveling devices is obtained. If the movement is suppressed, it is possible to avoid the possibility that the aircraft will meander due to a large difference in traveling resistance between the left and right crawler traveling devices when traveling straight in a differential state.

  Also, as the joining force of the friction clutch is increased, slippage of the friction clutch is less likely to occur, so that the differential suppression force of the left and right crawler traveling devices can be increased, and the turning performance can be reduced, Conversely, as the joining force of the friction clutch is reduced, slippage of the friction clutch is more likely to occur, so that the differential suppression force of the left and right crawler traveling devices can be reduced, and the turning performance can be improved. Therefore, for example, if the configuration is such that the joining force of the friction clutch that appears when the differential device is switched to the differential state can be changed, the setting change can change the turning characteristics during the turning operation. Also, if the friction force of the friction clutch is changed according to the braking force of the friction brake acting on one of the crawler type traveling devices, the braking force of the friction brake and the friction clutch Turning characteristics at the time of turning operation by changing the relationship between the bonding strength can be changed.

  In other words, it is possible to set a suitable turning characteristic according to the type of work and the state of the work place, so that workability can be improved.

  By the way, for example, it is conceivable to configure the differential switching device so as to show the non-differential state of the differential device by joining the friction clutch, but in this case, in order to secure the straight running property, As the clutch, it is necessary to use a large clutch having a large joint area with a strong joint force capable of reliably preventing the left and right crawler type traveling devices from slipping without slipping. In addition, since the size of the transmission case in which the differential switching device is mounted is increased, the manufacturing cost is increased and the size of the aircraft is increased.

  Therefore, in the present invention, the non-differential state of the differential device is caused to appear by engagement of the non-slip pawl clutch, and thereby, the manufacturing cost due to the enlargement of the differential switching device and the like is increased. Thus, the non-differential state of the differential device can be reliably displayed without causing a rise in the size of the aircraft and an increase in the size of the aircraft.

  Therefore, in addition to being able to improve the straightness when the vehicle is traveling straight in a differential state, the workability can be improved by setting the turning characteristics according to the type of work and the state of the work place, and further, the manufacturing cost can be improved. This has made it possible to reliably show the non-differential state of the differential device without causing a rise in the size of the aircraft and an increase in the size of the aircraft.

  As one of means for making the present invention more preferable, the claw clutch is disengaged from the differential switching device and the left and right friction brakes with the start of one of the friction brakes, and When the braking force of the brake is equal to or less than a predetermined value, the friction clutch is engaged, and when the braking force of the friction brake exceeds a predetermined value, the joining force of the friction clutch decreases as the braking force increases. The claw clutch is engaged so as to engage with the release of the friction brake.

  According to the above configuration, when one of the friction brakes is started to be braked, the pawl clutch is disengaged accordingly, so that the turning traveling is started, and the braking force of the one friction brake exceeds a predetermined value from the start of the turning. In the meantime, the braking force on one crawler traveling device is low, and the frictional clutch is joined to maximize the differential suppression force of the left and right crawler traveling devices. A slow turning state in which the crawler-type traveling device is driven at an irregular speed at a speed close to the constant speed appears.

  When the braking force of one of the friction brakes exceeds a predetermined value, as the excess amount increases, the braking force on one of the crawler-type traveling devices increases, and the joining force of the friction clutch decreases to cause slippage. Since the differential restraining force of the left and right crawler traveling devices is reduced by being easy to perform, one crawler traveling device is braked and decelerated according to the braking force of one friction brake, and the other When the crawler-type traveling device is in a turning state in which the speed is increased and the braking force of one of the friction brakes is at or near the maximum, the friction clutch is disengaged and the difference between the left and right crawler-type traveling devices cannot be suppressed. As a result, a sharp turning state in which the braking of one crawler traveling device is stopped and the driving speed of the other crawler traveling device is doubled, appears.

  Also, when one of the friction brakes is released, the claw clutch is engaged to prevent the differential between the left and right crawler traveling devices, so that a difference occurs in the traveling resistance between the left and right crawler traveling devices. As a result, a preferable straight-ahead state in which meandering of the body caused by the differential movement can be avoided appears.

  Therefore, the transition from straight running in which the left and right crawler-type traveling devices are prevented from being differential to gentle turning in which the left and right crawler-type traveling devices are driven at unequal speed in a state close to constant speed, The transition to the rapid turning travel in which the braking of the crawler traveling apparatus is stopped and the driving speed of the other crawler traveling apparatus is doubled, the transition from the rapid traveling to the above-mentioned gentle traveling, and the transition to the gentle traveling. The transition from the turning traveling to the straight traveling described above can be smoothly and continuously performed by a simple operation.

  FIG. 1 shows a traveling transmission structure of a combine, which is an example of a working machine, such that power from an engine 1 can be shifted in two high and low stages via a belt tension type traveling clutch 2. A mesh-type second sub-transmission that is transmitted to the configured first sub-transmission 3 of a hydraulic clutch type so that power from the first sub-transmission 3 can be shifted in two stages, high and low. 4, and the power from the second auxiliary transmission 4 is transmitted to a hydraulic clutch-type main transmission 5, which is configured to be able to switch between forward and reverse and to shift three forward speeds. 5 is transmitted to the left and right crawler type traveling devices 8 via the differential device 6 and the left and right axles 7.

  The power from the first auxiliary transmission 3 is transmitted as a working power to the harvesting / transporting unit 11 via the meshing type of transmission 9 and the belt type transmission 10.

  As shown in FIGS. 1 and 2, the differential device 6 includes a differential case 12 having an input gear 12 a meshing with a first output gear 5 a and a second output gear 5 b of the main transmission 5. A pair of differential pinions 13 which are integrally rotatable about a horizontal axis P1 and are rotatably supported around an axis P2 orthogonal to the horizontal axis P1 and mesh with the pair of differential pinions 13 The left and right side gears 14 are connected to each other, the axles 7 corresponding to the left and right side gears 14 are interlocked and connected, and each of the axles 7 is equipped with a friction brake 15 for steering.

  Between the differential case 12 and the right axle 7, the differential device 6 is provided with a non-differential state in which the left and right crawler type traveling devices 8 prevent the differential movement of the crawler type traveling device 8 and the left and right crawler type traveling. A differential switching device 16 is provided to allow the differential of the device 8 to be switched to a differential state in which the turning of the fuselage is enabled, and the differential switching device 16 is driven by the engagement of the pawl clutch 16A. 6 and the differential state of the differential device 6 is revealed by releasing the engagement of the pawl clutch 16A. In the differential state, the differential between the left and right crawler type traveling devices 8 due to the engagement of the friction clutch 16B. The pawl clutch 16A and the hydraulic friction clutch 16B are provided in parallel so that suppression is possible.

  As shown in FIG. 2, each of the left and right friction brakes 15 is actuated by a first hydraulic pump 20 via a sequence valve 19 by operating a first control valve 17 and a first pressure regulating valve 18 of a three-position switching type. When the oil is supplied to the corresponding first hydraulic cylinder 21 for steering, the braking force applied to the corresponding crawler-type traveling device 8 increases, and the hydraulic oil is discharged from the corresponding first hydraulic cylinder 21. Thus, the braking force applied to the corresponding crawler type traveling device 8 is reduced. The claw clutch 16 </ b> A meshes when the hydraulic oil from the second hydraulic pump 23 is supplied to the second hydraulic cylinder 24 by the operation of the second control valve 22 of the two-position switching type, and operates from the second hydraulic cylinder 24. The engagement is released by discharging the oil. The friction clutch 16B operates with the second pressure adjusting valve 25 so that the joining force is increased by supplying the working oil from the second hydraulic pump 23, and the joining force is decreased by discharging the working oil. Is configured. Reference numeral 26 shown in FIG. 2 is a high-pressure relief valve.

  The first control valve 17 is switched to a state in which the hydraulic oil is discharged from the first left and right hydraulic cylinders 21 when the steering lever 27 provided in the boarding operation section is operated to the neutral position N, and the steering lever 27 is turned on. When operated in the left turning operation area L, the state is switched to a state in which hydraulic oil is supplied to the first hydraulic cylinder 21 on the left. When the steering lever 27 is operated in the right turning operation area R, the first hydraulic cylinder on the right is operated. It is linked to a steering lever 27 so as to be able to switch to a state in which hydraulic oil is supplied to 21.

  When the steering lever 27 is operated to the neutral position N, the relief setting pressure of the first pressure regulating valve 18 is minimized, and the steering lever 27 is operated to the left or right turning operation area L, R. In this state, the steering lever 27 is linked to the steering lever 27 such that the relief setting pressure increases as the steering lever 27 is positioned further away from the neutral position N.

  When the steering lever 27 is operated to the neutral position N, the second control valve 22 is switched to a state in which hydraulic oil is supplied to the second hydraulic cylinder 24 and the friction clutch 16B, and the steering lever 27 is turned left or right. The operation lever L is connected to the steering lever 27 so that when the operation is performed in the operation range L or R, the operation oil is discharged from the second hydraulic cylinder 24 and is switched to a state in which the operation oil is supplied to the friction clutch 16B.

  The second pressure adjusting valve 25 is an operating area in which the steering lever 27 extends from the neutral position N where the braking force of the friction brake 15 is equal to or less than the predetermined value a to the predetermined positions La and Ra of the left and right turning operation areas L and R. , The relief set pressure becomes maximum, and the relief set pressure increases as the steering lever 27 is operated to the side farther from the neutral position N than the predetermined position La, Ra in the left or right turning operation area L, R. It is linked to the steering lever 27 so as to be smaller.

  That is, as shown in FIG. 3, the left and right friction brakes 15 and the differential switching device 16 are driven by the one of the left and right friction brakes 15 on the basis of the operation of the steering lever 27 and the claw clutch 16 </ b> A. Are disengaged and the friction clutch 16B is engaged when the braking force of the friction brake 15 is equal to or less than the predetermined value a, and when the braking force of the friction brake 15 exceeds the predetermined value a, the braking force becomes larger. The engagement force of the friction clutch 16 is reduced, and the pawl clutch 16 </ b> A is engaged so as to engage with the release of the friction brake 15.

  With the above configuration, when the steering lever 27 is operated from the neutral position N to one of the left and right turning operation areas L and R, one of the friction brakes 15 corresponding to the operation direction starts braking, and accordingly, the pawl clutch Since the engagement of the steering lever 16A is released, the turning traveling according to the operating direction of the steering lever 27 can be started, and in the turning start state, the steering lever 27 is in the left or right turning operation area L, R. By being located on the neutral position N side with respect to the predetermined positions La and Ra, the braking force on the one crawler type traveling device 8 in which the braking force of one friction brake 15 becomes equal to or less than the predetermined value a becomes low, and the friction force is reduced. Since the clutch 16B is completely connected, the differential suppression force on the left and right crawler traveling devices 8 is maximized, so that the left and right crawler traveling devices 8 are close to constant velocity. And it is capable of revealing the gentle turning state to be non-uniform driving state.

  Then, when the steering lever 27 is operated to the side farther from the neutral position N than the predetermined positions La, Ra in the left or right turning operation area L, R, one of the turning levers 27 becomes farther away from the neutral position N than the predetermined position La, Ra. The braking force of the friction brake 15 against the corresponding crawler-type traveling device 8 is increased, and the joining force of the friction clutch 16B is reduced so that slippage is likely to occur. Is reduced, the braking state of one crawler-type traveling device 8 is decelerated and the other crawler-type traveling device 8 is accelerated in accordance with the operation amount of one friction brake 15, and the turning state is now displayed. When the operation amount from the neutral position N of the steering lever 27 is maximized, the braking force of one friction brake 15 on the corresponding crawler type traveling device 8 is reduced. As the friction clutch 16B is disengaged and the differential between the left and right crawler traveling devices 8 is no longer suppressed, the braking of one crawler traveling device 8 is stopped, and the other crawler traveling device 8 is stopped. A sharp turning state in which the driving speed of No. 8 is doubled can be realized.

  Conversely, when the steering lever 27 is operated from the state where the operation amount from the neutral position N is maximized to the neutral position N side, as the steering lever 27 approaches the predetermined positions La and Ra, the response of one of the friction brakes 15 increases. The braking force applied to the crawler-type traveling device 8 becomes smaller, and the joining force of the friction clutch 16B increases, so that slippage is less likely to occur. A turning state in which the speed of one crawler-type traveling device 8 is increased and the other crawler-type traveling device 8 is decelerated in accordance with the operation amount of one friction brake 15, and the steering lever When 27 reaches the predetermined positions La and Ra, the braking force on one crawler traveling device 8 in which the braking force of one friction brake 15 is equal to or less than a predetermined value a is low, and Since the frictional clutch 16B is completely joined, the differential restraining force on the left and right crawler traveling devices 8 is maximized, so that the left and right crawler traveling devices 8 are driven at an irregular speed near a constant speed. A gentle turning state can be realized.

  Then, when the steering lever 27 is operated from the left or right turning operation area L, R to the neutral position N, one of the friction brakes 15 is released, and the claw clutch 16A is meshed with it, so that the left and right crawler type traveling is performed. Since the differential of the device 8 is prevented, a preferable straight traveling state in which the right and left crawler type traveling devices 8 can avoid the meandering of the airframe due to the difference in the traveling resistance and the difference between the traveling resistances can be avoided. Can be done.

  In other words, the switching operation of the claw clutch 16A by the operation of the steering lever 27 prevents the differential between the left and right crawler-type traveling devices 8 from being stopped and the linear traveling state in which the left and right crawler-type traveling devices 8 are driven at a constant speed. In the turning state, the braking force of the friction brake 15 is adjusted by operating the steering lever 27 and the differential suppression force of the friction clutch 16 is generated. In the adjustment, the left and right crawler-type traveling devices 8 are driven at irregular speeds at a speed close to the constant speed, and the braking of one crawler-type traveling device 8 is stopped and the other crawler-type traveling device 8 is stopped. A sudden turning state in which the driving speed has been doubled can be made to appear in a stepless manner, so that a simple operation of the steering lever 27 allows a transition from straight running to gentle turning. Transition, gentle turning Transition to sudden turning from the row, the transition from rapid turning travel to slow turning, and, the transition to the straight running from slow turning is smoothly able to perform a series.

(Another embodiment)
Hereinafter, other embodiments of the present invention will be listed.
[1] The working machine may be a backhoe, a tractor, or the like as long as the working machine travels with a pair of left and right crawler traveling devices 8.

[2] The left and right friction brakes 15 for steering may be configured to be used also as traveling brakes.

[3] Hydraulic oil from the first pump 20 is supplied to the corresponding first hydraulic cylinder 21 to the left and right steering friction brakes 15 so that the braking force on the corresponding crawler-type traveling device 8 decreases, By adopting a negative type in which the braking force against the corresponding crawler type traveling device 8 is increased by discharging the hydraulic oil from the corresponding first cylinder 21, the left and right friction brakes 15 can be used for the parking brake. You may comprise.

[4] The claw clutch 16A is disengaged from the left and right friction brakes 15 and the differential switching device 16 with the start of braking of one of the left and right friction brakes 15 and the friction clutch becomes larger as the braking force of the friction brake 15 increases. The engagement force of the friction clutch 16B may be reduced so that the pawl clutch 16A is engaged and the friction clutch 16B is completely engaged with the release of the friction brake 15.

Sectional view showing the traveling transmission structure of the combine Hydraulic circuit diagram for steering Diagram showing the relationship between the differential switching device and the friction brake

Explanation of reference numerals

6 Differential device 8 Crawler type traveling device 15 Friction brake 16 Differential switching device

Claims (1)

  A power for traveling is transmitted to the left and right crawler type traveling devices via a differential device, and the differential device is in a non-differential state in which the differential of the left and right crawler type traveling devices is blocked and the aircraft advances straight. A differential switching device for switching between the left and right crawler type traveling devices to a differential state allowing the body to rotate while allowing a differential between the left and right crawler traveling devices, and traveling of a working machine equipped with a friction brake for steering. Transmission structure.

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