JP5086752B2 - Work vehicle turning control device - Google Patents

Description

  The present invention drives the drive state of the pair of left and right traveling devices at the same speed in a straight drive state and drives the one on the outer side of the turn in the direction of the airframe and propels the one on the inner side of the turn in the direction of the airframe. It is possible to switch to a turning drive state in which the force is reduced, and is provided with a travel drive means having a hydraulically operated frictional hydraulic clutch for switching to a plurality of turning states in the turning drive state, and supplied from a hydraulic source Supply pressure adjusting means for changing and adjusting the supply pressure of pressure oil to the friction type hydraulic clutch, turning state selecting means for selecting one of the plurality of turning states, the straight running state, and the turning drive state Steering command means for selecting, and operation control means for operating the travel driving means and the supply pressure adjusting means based on commands of the turning state selecting means and the steering command means are provided. On turning control device for a work vehicle.

  Conventionally, for example, the above-described turning control device for a work vehicle is applied to a combine as an example of a work vehicle. In other words, the travel drive means includes left and right side clutches that can be turned on and off separately for the transmission state to the pair of left and right travel devices in order to switch between the straight travel state and the turning drive state, and a plurality of the frictional hydraulic pressures. As a friction type hydraulic clutch, the friction type hydraulic clutch for exclusive use for revealing the sudden turning state which drives the traveling device inside the turn so as to advance in the direction opposite to the aircraft traveling direction, and the traveling device inside the turn as the friction hydraulic clutch. Dedicated friction hydraulic clutch for revealing a gentle turning state in which the turning of the vehicle stops or substantially stops, ultra-slow, in which the traveling device on the inner side of the turning rotates at a lower speed than the traveling device on the outer side of the turning A plurality of swiveling states as described above can be provided by providing a dedicated friction hydraulic clutch for displaying a swiveling state and selectively putting one of the friction hydraulic clutches into an engaged state. A steering lever as the steering command means, the supply pressure adjusting means being configured by a variable relief valve capable of changing and adjusting the supply pressure to the selected friction type hydraulic clutch by manual operation; In some cases, the operation pressure is changed and adjusted by adjusting the opening of the variable relief valve based on the operation command. Then, the steering lever and the supply pressure adjusting means as the steering command means so that the operating pressure increases as the amount of movement in the direction away from the rectilinear command position commanding the straight traveling state increases. The variable relief valve is mechanically linked (for example, see Patent Document 1).

  In the above configuration, when turning the work vehicle, the driver selects one of a plurality of turning states according to the working state at that time and operates the steering command means to make the turning drive. The turning state of can be obtained.

JP 7-47973 A

  In the above conventional configuration, as described above, a desired turning state suitable for a work situation can be obtained by selecting any one of a plurality of turning states and operating the steering command means to perform turning traveling. However, a sudden turning state in which the traveling device inside the turn is driven so as to travel in a direction opposite to the advancing direction of the aircraft, a stopped turning state in which the turning of the traveling device inside the turn is stopped or substantially stopped, and a traveling device inside the turn The friction type hydraulic clutch is provided with a friction type hydraulic clutch dedicated to each turning state corresponding to each of the low speed turning turning states that rotate at a lower speed than the traveling device outside the turning in the aircraft traveling direction. This increases the number of the motors, complicates the structure of the travel drive means, and has the disadvantage of increasing costs.

  An object of the present invention is to switch the traveling drive means to a plurality of turning states and to make a good turn traveling in each turning state, and to simplify the structure of the traveling drive means. It is in the point which provides the turning control apparatus of the working vehicle which becomes.

The turning control device for a work vehicle according to the present invention drives the driving state of the pair of left and right traveling devices at the same speed in a straight driving state and drives the outside of the turning in the forward direction of the vehicle and the inside of the turning. Traveling drive means comprising a hydraulically operated frictional hydraulic clutch for switching to a plurality of turning states in the turning drive state, which can be switched to a turning drive state for reducing the propulsive force in the advancing direction of the vehicle. When,
Supply pressure adjusting means for changing and adjusting the supply pressure of the pressure oil supplied from the hydraulic source to the friction type hydraulic clutch;
A turning state selection means for selecting one of the plurality of turning states;
Steering command means for selecting the straight traveling state and the turning drive state;
Operation control means for operating the travel drive means and the supply pressure adjusting means based on the commands of the turning state selection means and the steering command means;
The first characteristic configuration is that the travel drive means is in a direction opposite to the airframe traveling direction transmitted to the travel device inside the turn of the pair of left and right travel devices as the plurality of turning states in the turning drive state. By changing the magnitude of the propulsive force that advances in the forward direction by the friction type hydraulic clutch, the sudden turning state that drives the traveling device inside the turning so as to advance in the direction opposite to the aircraft traveling direction and the traveling device inside the turning It is configured to switch to a stop turning state in which the rotation stops or substantially stops,
In the turning drive state, the operation control means responds to the sudden turning operation pressure corresponding to the sudden turning state and the stop turning state based on the command of the selection state selecting means. Configured to operate the supply pressure adjusting means in order to adjust to the stop turning operation pressure .
When the operation control means is switched from the stop turning state to the sudden turning state by the turning state selection means, and the target value commanded by the steering command means is not the maximum target value, the target The point is that the value is increased under the setting increase condition .

  According to the first characteristic configuration, when the sudden turning state is selected by the turning state selection unit, the operation control unit sets the operation pressure of the friction hydraulic clutch to the sudden turning operation pressure corresponding to the sudden turning state. The supply pressure adjusting means is operated to adjust the driving force so that the traveling driving means transmits the magnitude of the propulsive force that travels in the direction opposite to the aircraft traveling direction transmitted to the traveling device inside the turning of the pair of left and right traveling devices. By changing the friction type hydraulic clutch, the traveling device on the inner side of the turning is switched to a sudden turning state in which the traveling device is driven so as to travel in the direction opposite to the aircraft traveling direction.

  When the stop turning state is selected by the turning state selection means, the operation control means supplies a supply pressure to adjust the operation pressure of the friction hydraulic clutch to a stop turning operation pressure corresponding to the stop turning state. By operating the adjusting means, the friction drive clutch is used to determine the magnitude of the propulsive force that travels in the direction opposite to the aircraft traveling direction transmitted to the traveling device inside the turning of the pair of left and right traveling devices. By changing, the rotation of the traveling device inside the turning is switched to a stopped turning state where the turning is stopped or substantially stopped. In other words, since the traveling device on the outer side of the turn is driven in the aircraft traveling direction, the traveling drive device tries to rotate in the aircraft traveling direction by the traveling driving force, but by adjusting the operating pressure on the friction hydraulic clutch, It acts as a pseudo-brake to prevent the rotation.

As a result, the travel drive means changes and adjusts the operation pressure of one frictional hydraulic clutch to switch between the state of turning in the sudden turning state and the state of turning in the stopped turning state. Thus, it is possible to perform turning in each turning state.
That is, regardless of whether the turning state selection means selects the sudden turning state or the stopped turning state, the selected turning state is obtained by adjusting the operating pressure of one frictional hydraulic clutch. Therefore, it is not necessary to provide a dedicated friction type hydraulic clutch for displaying only the sudden turning state and a dedicated friction type hydraulic clutch for displaying only the stopped turning state. The configuration can be simplified by reducing the number of parts.

Therefore, according to the first characteristic configuration, the traveling drive means can be switched to a plurality of turning states and the turning drive can be favorably performed in each turning state, but the structure of the traveling drive means is simplified. Thus, it has become possible to provide a turning control device for a work vehicle.
According to the first characteristic configuration, the stop turning state is selected by the turning state selection means, and the sudden turning state is changed by the turning state selection means from a state where the turning state is turned. If the target value commanded by the steering command means is not the maximum target value when the turning state is selected and switched, the operation control means sets the target value commanded by the steering command means to the setting increase condition It is increased by.
In other words, because the frictional hydraulic clutch that is subject to change in operating pressure is the same regardless of whether it is in a stop turning state or a sudden turning state, the target value of the steering command means and the target operation For example, only when the target value commanded by the steering command means is the maximum target value, the operation pressure is larger than the operation pressure corresponding to the stop turning state in the sudden turning state. It is possible to consider a configuration that adjusts to However, with such a configuration, when the target value commanded by the steering command means is not the maximum target value, the turning state changes even though the sudden turning state is selected by the turning state selection means. Since the driver does not know the change in the turning state, there are disadvantages such as feeling dissatisfied or feeling uncomfortable.
Therefore, when the target value commanded by the steering command means is not the maximum target value, the operation control means increases the target value commanded by the steering command means under the setting increase condition. However, the turning operation can be performed in a state in which the driver feels dissatisfied or uncomfortable.
Therefore, as long as turning is commanded by the steering command means, there is no disadvantage that the driver feels dissatisfied or uncomfortable even when switching from the stopped turning state to the sudden turning state. In this way, it is possible to provide a turning control device for a work vehicle that can perform a turning operation.

According to a second characteristic configuration of the present invention, in addition to the first characteristic configuration, the traveling drive unit is configured as a plurality of turning states in the turning driving state as a plurality of turning states in the turning device inside the turning pair. By changing the magnitude of the propulsive force that travels in the direction opposite to the direction of travel of the airframe transmitted to the frictional hydraulic clutch, the sudden turning state, the stop turning state, and the traveling device inside the turning can be It is configured to switch to a low-speed rotation turning state that rotates at a lower speed than the traveling device outside the turning in the traveling direction,
In the turning driving state, the operation control means responds to the sudden turning operation pressure corresponding to the sudden turning state, the operation pressure of the friction hydraulic clutch based on the command of the turning state selection means, and the stop turning state. The supply pressure adjusting means is operated to adjust the operation pressure for stop turning and the operation pressure for low speed turning turning corresponding to the low speed turning turning state.

  According to the second characteristic configuration, when the sudden turning state is selected by the turning state selection means, the operation control means adjusts the operation pressure of the friction hydraulic clutch to the sudden turning operation pressure corresponding to the sudden turning state. Since the supply pressure adjusting means is operated as much as possible, the traveling drive means is switched to the sudden turning state. When the stop turning state is selected by the turning state selection means, the operation control means adjusts the supply pressure to adjust the operation pressure of the friction hydraulic clutch to the stop turning operation pressure corresponding to the stop turning state. Since the means is operated, the traveling drive means is switched to the stop turning state.

  Then, when the turning state selecting means selects the low speed turning turning state, the operation control means changes the operating pressure of the friction type hydraulic clutch to the low speed turning turning operation pressure corresponding to the low speed turning turning state. The supply pressure adjusting means is operated to adjust. As a result, the traveling drive means is switched to a low-speed rotational turning state in which the traveling device inside the turning rotates at a lower speed than the traveling device outside the turning in the aircraft traveling direction.

  As a result, the travel drive means can change and adjust the operating pressure of one frictional hydraulic clutch to reveal not only the sudden turning state and the stop turning state but also the low-speed turning turning state. Therefore, it is not necessary to provide a dedicated friction type hydraulic clutch for making each turning state appear, and the number of parts can be reduced and the configuration can be simplified.

  Therefore, according to the second characteristic configuration, it is possible to switch the traveling drive means to a plurality of turning states and perform turning in each turning state, but it is possible to further simplify the structure. The work vehicle turning control device can be provided.

  According to a third aspect of the present invention, in addition to the first characteristic configuration, the supply pressure adjusting means is configured to change and adjust an opening degree of an oil passage through which the pressure oil is supplied to the friction hydraulic clutch. There is in point.

  According to the third characteristic configuration, the supply pressure adjusting means changes and adjusts the opening degree of the oil passage through which the pressure oil is supplied to the friction hydraulic clutch. Supply pressure can be adjusted appropriately. If comprised in this way, the excess hydraulic oil can be drained as it is, for example, what adjusts the pressure of the relief valve interposed in the oil path may increase the temperature of the hydraulic oil. However, it is possible to appropriately adjust the supply pressure while avoiding such a temperature rise of the hydraulic oil.

  Therefore, according to the third characteristic configuration, it is possible to provide a turning control device for a work vehicle that can appropriately adjust the supply pressure of the pressure oil to the friction hydraulic clutch while avoiding the temperature rise of the hydraulic oil. It was.

  According to a fourth feature configuration of the present invention, in addition to any one of the first feature configuration to the third feature configuration, the steering command means continuously outputs a target value between a minimum target value and a maximum target value. And the operation control means selects the operation pressure when the maximum target value is commanded for the operation pressure of the friction hydraulic clutch based on the command of the steering command means. The supply pressure adjusting means is configured to be operated so that the larger the command value is commanded, the larger the command value corresponding to the turning state selected by the means.

  According to the fourth feature configuration, since the steering command means can continuously command the target value between the minimum target value and the maximum target value, the target value is set to the minimum target by operating the steering operation means. The turning can be arbitrarily changed between the value and the maximum target value, and the operation pressure when the maximum target value is commanded is selected by the turning state selection means when the operation pressure of the friction hydraulic clutch is commanded Since the supply pressure adjusting means is operated so that the larger the target value is commanded so that the operation pressure corresponding to the state is commanded, the turning selected by the turning state selecting means by the operation of the steering operation means The operating pressure of the friction hydraulic clutch can be changed and adjusted to an arbitrary value in a state corresponding to the state.

  Therefore, according to the fourth feature configuration, the turning state desired by the driver by changing and adjusting the operation pressure of the friction hydraulic clutch to an arbitrary value in a state corresponding to the turning state selected by the turning state selection means. In this way, it is possible to provide a turning control device for a work vehicle that can turn at the same time.

The fifth characteristic configuration of the present invention, in addition to the fourth feature configuration, the operation control means sets with a operating pressure for adjusting the target value commanded by said steering command means over time The supply pressure adjusting means is operated so as to repeatedly vary the amount.

According to the fifth characteristic configuration, since the operating pressure to be adjusted with respect to the target value commanded by the steering command means is repeatedly varied over time, the operating pressure of the friction hydraulic clutch is changed. In the case where the turning state is switched by changing and adjusting to an arbitrary value, the turning state can be switched as smoothly as possible.

  If the explanation is added, there is a risk that it is difficult to switch the turning state when adjusting the operation pressure of the friction hydraulic clutch to the operation pressure corresponding to the target value commanded by the steering command means. . In particular, when the turning drive state is selected by the steering operation means and the turning traveling is performed, the operation pressure of the friction hydraulic clutch corresponds to the sudden turning state from the state corresponding to the stop turning state. In the case where the operation pressure is changed, the traveling device inside the turn is stopped or substantially stopped, so when the traveling device is switched to a state of traveling in the direction opposite to the aircraft traveling direction, the steering command In the case of adjusting the operation pressure corresponding to the target value commanded by the means, since the fluctuation range of the operation pressure of the friction type hydraulic clutch is small, the traveling device inside the turning that is stopped or substantially stopped is referred to as the aircraft traveling direction. There is a possibility that the driving resistance when switching to the state of traveling in the reverse direction is large and it is difficult to switch the turning state.

  Therefore, by repeatedly varying the operating pressure adjusted with respect to the target value commanded by the steering command means by a set amount as time elapses, a state in which the operating pressure temporarily increases is repeatedly displayed. Thus, for example, even in the case of switching from the stopped turning state to the sudden turning state, it becomes easy to overcome the driving resistance as described above and change the driving state of the traveling device inside the turning.

Therefore, according to the fifth characteristic configuration, it is possible to provide a turning control device for a work vehicle that can switch the turning state as smoothly as possible.

  Hereinafter, the case where the embodiment of the turning control device for a work vehicle according to the present invention is applied to a combine as an example of the work vehicle will be described with reference to the drawings.

  As shown in FIG. 1, a cutting part 4 is supported at a front part of a vehicle body supported by right and left crawler travel devices 1 and 1 by a lifting cylinder 3 so as to be driven up and down around a horizontal axis P1. A driving unit 5 is provided on the right side of the front part of the vehicle, an engine 7 is provided on the lower side of the driving seat 6 of the driving unit 5, a threshing device 8 is provided on the left side of the rear part of the vehicle body, and a glen on the right side of the rear part of the vehicle body. A tank 9 is provided to constitute a self-removing combine that is an example of a work vehicle.

  As shown in FIG. 2, the power of the engine 7 is transmitted to the input shaft of the hydrostatic continuously variable transmission 11 for traveling speed change via the transmission belt 19, the input pulley 17, and the input shaft 16. Is transmitted to the cutting unit 4 via the transmission belt 20 and the hydrostatic continuously variable transmission 21 for cutting and shifting.

Next, the transmission mechanism inside the mission case will be described with reference to FIG.
An input shaft 22 is supported on the upper part of the transmission case 10, and transmission gears 23 and 24 are fixed to the input shaft 22 by a spline structure. An output shaft 11c of the hydrostatic continuously variable transmission 11 is inserted into the transmission case 10 and connected to the transmission gear 24 (input shaft 22) by a spline structure. Further, a high-speed gear 25 and a low-speed gear 26 are externally fitted to the sub-transmission transmission shaft 27 supported on the upper portion of the transmission case 10 so as to be relatively rotatable, and the transmission gear 23 and the high-speed gear 25, the transmission gear 24 and the low-speed gear 26 are fitted. The shift member 28 is externally fitted to the sub-transmission transmission shaft 27 so as to be integrally rotatable and slidable by a spline structure. The transmission gear 23 and the high-speed gear 25, the transmission gear 24 and the low-speed gear 26, and the shift member 28 constitute an auxiliary transmission, and the input shaft 22 is engaged by engaging the shift member 28 with the high-speed and low-speed gears 25 and 26. Is transmitted to the sub-transmission transmission shaft 27 after being shifted to high and low two stages (low speed and high speed position).
The auxiliary transmission is normally slid to a position where the shift member 28 meshes with the high speed gear 25 to set the high speed position.

  A linear transmission shaft 29 is supported at the lower part of the transmission case 10, and a transmission gear 31 is fixed to the linear transmission shaft 29. The transmission gear 31 is engaged with a transmission gear 30 fixed to the auxiliary transmission transmission shaft 27. Yes. Further, a pair of left and right output gears 32R and 32L are externally fitted to the linear transmission shaft 29 so as to be relatively rotatable, and a pair of left and right occlusion portions 33R and 33L are integrally rotated with the linear transmission shaft 29 by a spline structure. It is slidably fitted outside. And the right side clutch 34 is comprised between the right output gear 32R and the right occlusion part 33R, and the left side clutch 34 is comprised between the left output gear 32L and the left occlusion part 33L.

Next, the right and left side clutches 34 will be described.
Spline portions are formed on the outer surfaces of the right and left side portions of the straight transmission shaft 29, and the right occlusion portion 33R and the left occlusion portion 33L are externally fitted to the spline portion of the straight movement transmission shaft 29 so as to be integrally rotatable and slidable. The receiving member 40 is externally fitted to the spline portion of the linear transmission shaft 29 so as to be integrally rotatable. The right and left occlusal portions 33R and 33L are urged by the receiving member 40 and the spring 41 to the occlusal side of the right and left output gears 32R and 32L. The right and left occlusal portions 33R and 33L are engaged with the right and left output gears 32R and 32L, so that the right and left side clutches 34 are in a transmission state. And transmitted to the right and left crawler travel devices 1 via the left side clutch 34.

  Further, by supplying hydraulic oil into the oil chambers formed between the right and left output gears 32R and 32L and the right and left occlusion portions 33R and 33L, the right and left occlusion portions 33R and 33L The right and left occlusal portions 33R and 33L are slid to the side where they are separated against the biasing force of the spring 41, and the right and left side clutches 34 are in a clutch disengaged state (disengaged state). When the hydraulic oil is discharged, the right and left side clutches 34 are engaged (transmission state) by the biasing force of the spring 41.

  The left and right transmission shafts 35 are supported on the same axis so as to be arranged side by side on the same axis, and the left and right transmission gears 36 fixed to the left and right transmission shafts 35 are connected to the right output gear 32R and the left. The left and right transmission gears 37 fixed to the left and right transmission shafts 35 are engaged with the transmission gears 39 fixed to the right and left axles 38, respectively. The right and left axles 38 are connected to the right and left crawler travel device 1 sprockets.

  If both the left and right side clutches 34 are engaged, the power of the input shaft 22 is transmitted to the sub-transmission transmission shaft 27, the transmission gears 30 and 31, the straight transmission shaft 29, the right and left side clutches 34, When the right and left output gears 32R and 32L, the transmission gear 36, the transmission shaft 35, the transmission gears 37 and 39, and the right and left axles 38 are transmitted to the right and left crawler travel devices 1, the aircraft goes straight. It becomes the transmission state which runs in the state.

Next, the structure of the turning transmission system for turning the vehicle body will be described.
A transmission shaft 44 is supported in the transmission case 10, and a transmission gear 45 fitted on the transmission shaft 44 so as to be relatively rotatable is engaged with a gear portion on the outer periphery of the right occlusion portion 33 </ b> R. A slow turning clutch 46 is provided between the gear 45. The slow swing clutch 46 is configured as a friction multi-plate type, and is operated to a transmission state (on state) when hydraulic oil is supplied, and is operated to a cut-off state (off state) when the hydraulic oil is discharged. .

  A revolving clutch case 47 is fitted on the linear transmission shaft 29 so as to be relatively rotatable, and a transmission gear 48 fixed to the transmission shaft 44 and a transmission gear 47 a on the outer periphery of the revolving clutch case 47 are engaged with each other. The turning clutch case 47 is configured to be bilaterally symmetrical, and a right and left turning clutch 49 is formed between the turning clutch case 47 and the right and left output gears 32R and 32L. The right and left turning clutch 49 is configured as a friction multi-plate type, and is operated in a transmission state by supplying hydraulic oil. The right and left turning clutches 49 are arranged so that the friction plates are dense with each other, and the right and left turning clutches 49 are in a semi-transmission state even when the hydraulic oil is discharged. .

  When the slow swing clutch 46 is operated in the transmission state, the power of the straight drive shaft 29 is used for the straight drive via the right occlusal portion 33R, the transmission gear 45, the slow swing clutch 46, the transmission shaft 44, and the transmission gear 48. Rotation in the same direction as the transmission shaft 29 is transmitted to the turning clutch case 47 as power lower than that of the linear transmission shaft 29. When one of the right and left side clutches 34 is operated in a disconnected state and the one of the right or left turning clutch 49 on the side where the side clutch 34 is disconnected is operated in a transmission state, a transmission state is established. Through the turning clutch 49, the power in the same direction as that of the straight transmission shaft 29 is transmitted to one of the right and left output gears 32R and 32L by the rotation in the same direction as that of the straight transmission shaft 29. Low speed power is transmitted to the traveling device 1. At that time, the power of the straight drive shaft 29 is transmitted as it is to the other of the right or left output gears 32R, 32L.

  A transmission gear 52 is fitted on the transmission shaft 44 so as to be relatively rotatable. The transmission gear 52 is engaged with a transmission gear 51 provided on the auxiliary transmission transmission shaft 27 so as to be integrally rotatable. A reverse clutch 53 is provided between the transmission shaft 44 and the transmission gear 52. The reverse clutch 53 is configured as a frictional multi-plate type, and is operated to a transmission state (ON state) when hydraulic oil is supplied, and is operated to a cutoff state (OFF state) when the hydraulic oil is discharged. The reverse clutch 53 can be operated in a braking state as will be described later by adjusting the supply pressure of the hydraulic oil.

  When the reverse clutch 53 is operated in the transmission state, the power of the sub-transmission transmission shaft 27 is reverse to the linear transmission shaft 29 via the transmission gears 51 and 52, the reverse clutch 53, the transmission shaft 44 and the transmission gear 48. It is transmitted to the turning clutch case 47 as directional rotation power. When one of the right and left side clutches 34 is operated in a disconnected state and the one of the right or left turning clutch 49 on the side where the side clutch 34 is disconnected is operated in a transmission state, a transmission state is established. The rotational power in the direction opposite to that of the straight transmission shaft 29 is transmitted to one of the right or left output gears 32R and 32L via the turning clutch 49, and the reverse rotation is transmitted to the traveling device 1 on the corresponding side. Power is transmitted. At that time, the power of the straight drive shaft 29 is transmitted as it is to the other of the right or left output gears 32R, 32L.

  In addition, when the operation pressure is adjusted to prevent the rotation of the transmission shaft 44 by adjusting the supply pressure of the hydraulic oil, the brake can be brought into a braking state. In this braking state, the transmission shaft 44 and the transmission gear 48 are set. Through this, the turning clutch case 47 enters the braking state. When one of the right and left side clutches 34 is operated to the disconnected state, and the one of the right or left turning clutch 49 on the side where the side clutch 34 is disconnected is operated to the transmission state, the right or left side clutch 34 is operated. Of the output gears 32R and 32L, the side where the side clutch 34 is not disengaged is in a braking state, and the power on the opposite side transmits the power of the straight transmission shaft 29 as it is.

  Accordingly, each of the slow swing clutch 46 and the reverse clutch 53 corresponds to the frictional hydraulic clutch M, and the drive state of the plurality of frictional hydraulic clutches M and the pair of left and right traveling devices 1 is a straight drive state. The transmission mechanism provided in the transmission case 10 as described above, which includes the left and right side clutches 34 for switching to the turning drive state as the main components, drives the drive state of the pair of left and right traveling devices 1 at the same speed. The swivel drive state can be switched between a straight drive state to drive and a swivel drive state in which the outer one of them is driven in the direction of travel of the airframe and the propulsion force of the inner side of the turn is reduced in the direction of travel of the airframe. This corresponds to the traveling drive means 100 having a hydraulically operated frictional hydraulic clutch M for switching to a plurality of turning states in the state.

Next, the operation of the hydrostatic continuously variable transmission 11 for traveling speed change will be described with reference to FIG.
The pump 11P of the hydrostatic continuously variable transmission 11 is configured to be continuously variable from the neutral position N and the neutral position N to the high speed side of the forward F and the high speed side of the reverse R. The hydrostatic continuously variable transmission Eleven motors 11M are configured to be variable in two levels. A hydraulic cylinder 59 for operating the swash plate of the pump 11P of the hydrostatic continuously variable transmission 11 and a control valve 60 for supplying / discharging hydraulic oil to / from the hydraulic cylinder 59 are provided, and a shift lever 61 provided in the operating unit 5 is provided. And the control valve 60 are mechanically linked. Thus, by operating the speed change lever 61, the control valve 60 is operated and the hydraulic cylinder 59 is operated, and the pump 11P of the hydrostatic continuously variable transmission 11 is tilted to a position corresponding to the operation position of the speed change lever 61. Operate the board.

  A hydraulic cylinder 62 that operates the swash plate of the motor 11M of the hydrostatic continuously variable transmission 11 and an electromagnetically operated control valve 63 that supplies and discharges hydraulic oil to and from the hydraulic cylinder 62 are provided. A shift switch 61a is provided in the unit, and an operation signal of the shift switch 61a of the shift lever 61 is input to a control device 64 including a microcomputer. Thus, by operating the speed change switch 61a of the speed change lever 61, the control valve 63 is operated by the control device 64, the hydraulic cylinder 62 is operated, and the swash plate of the motor 11M of the hydrostatic continuously variable transmission 11 is operated at high speed. And it is the structure operated to a low-speed position.

  An operation position sensor 65 for detecting the operation position of the shift lever 61 is provided, and left and right axle rotation sensors 66R and 66L for detecting the rotation speeds of the left and right axles for detecting the traveling speed of the airframe are provided. Detection values of the position sensor 65 and the left and right axle rotation sensors 66R and 66L are input to the control device 64. Detection of whether the swash plate of the motor 11M of the hydrostatic continuously variable transmission 11 is at the high speed position or the low speed position is recognized by the control device 64 based on the operation signal of the speed change switch 61a of the speed change lever 61. As a result, the subtransmission (shift member 28) is determined based on the operating position of the pump 11P and the motor 11M of the hydrostatic continuously variable transmission 11 and the traveling speed of the airframe determined from the average value of the detected values of the left and right axle rotation sensors 66R and 66L. Can be recognized as a high speed position or a low speed position.

Next, the hydraulic unit 57 that supplies and discharges hydraulic oil to and from the right and left side clutches 34 (the right and left occlusion portions 33R and 33L), the right and left turning clutch 49, the slow turning clutch 46, and the reverse rotation clutch 53. explain.
As shown in FIG. 4, the hydraulic unit 57 includes a right turn control valve 67, a left turn control valve 68, a relief valve 69, an unload valve 70, a proportional control valve 71, a turn switching control valve 72, a super-reliable point. A turning pilot valve 74 is provided. The external pipe 58 from the hydraulic pump 56 driven by the output shaft 11 c of the hydrostatic continuously variable transmission 11 is connected to the hydraulic unit 57, and the right turning control valve 67 is the oil path 29 b of the straight transmission shaft 29. Are connected to the right side clutch 34 and the right turning clutch 49, and the left turning control valve 68 is connected to the left side clutch 34 and the left turning clutch 49 via the oil passage 29b of the straight transmission shaft 29. ing.

  The right turn control valve 67 and the left turn control valve 68 are configured by electromagnetic operation that can be switched to two positions of supply positions 67a and 68a and discharge positions 67b and 68b, respectively. The return is energized. The unload valve 70 is configured in an electromagnetic operation type that can be switched between two positions of a blocking position 70a and a discharging position 70b, and is urged to return to the blocking position 70a. A proportional control valve 71 and a turning switching control valve 72 are connected in series to an oil passage 75 branched from between the right and left turning control valves 67 and 68 and the oil passage 29b of the transmission shaft 29 for straight travel. A switching control valve 72 is connected to the slow swing clutch 46 and the reverse clutch 53 via an oil passage 44 a of the transmission shaft 44.

  The proportional control valve 71 is constituted by an electromagnetic proportional pressure reducing valve, and changes and adjusts a control current supplied from the control device 64 as will be described later, whereby the friction type hydraulic clutches M ( The supply pressure to the slow turning clutch 46 and the reverse clutch 53) can be changed and adjusted. Accordingly, the proportional control valve 71 constitutes a supply pressure adjusting means for changing and adjusting the supply pressure of the pressure oil supplied from the hydraulic source to the friction hydraulic clutch M.

  The turning switching control valve 72 is configured as a pilot operated type that can be freely operated at the slow turning position 72a and the super turning position 72c, and is urged to return to the slow turning position 72a. A super turning pilot valve 74 is configured so that the pilot hydraulic oil branched from the oil passage 75 is supplied to the turning switching control valve 72 and operated to the super turning position 72c. The super pivot pilot valve 74 has a supply position for supplying pilot hydraulic oil to the turning switching control valve 72 and a stop position for stopping the supply of pilot hydraulic oil and returning the turning switching control valve 72 to the slow turning position 72a. These are electromagnetically operated so that they can be switched to the two positions and are urged to return to the stop position.

  The right turn control valve 67, the left turn control valve 68, the unload valve 70, the proportional control valve 71, and the super pivot pilot valve 74 are controlled by a control device 64 as described later.

  Then, as shown in FIG. 5, the return command is urged to return to the straight command position N, and the turn command operation region extends from the straight command position N to the maximum operation position Rm on the right side and the maximum operation position Lm on the left side. A swing lever 77 capable of swinging operation is provided in the operation unit 5, and a swing lever sensor 80 is provided as a turn command position detecting means for detecting an operation position of the swing lever 77. It is input to the control device 64.

  The swivel lever 77 can be freely moved over the straight command position N and the swivel command operation area connected thereto, and the swivel lever sensor 80 has a maximum operation position (Rm, The detection information corresponding to the target turning force that increases as the movement to Lm) is commanded to the control device 64, and the steering command means 200 is constituted by the turning lever 77 and the turning lever sensor 80. Therefore, the steering command means 200 is configured to continuously command a target value between the minimum target value and the maximum target value.

  Further, a turning mode switch 78 for instructing to switch the turning state to a slow turning state as a low-speed turning state, a belief turning state as a stop turning state, and a super faith turning state as a sudden turning state is provided to the operation unit 5. The operation position of the turning mode switch 78 is input to the control device 64, and the turning mode switch 78 has a gentle turning position corresponding to the gentle turning state, a belief turning position corresponding to the belief turning state, The friction hydraulic clutch M is configured to be freely switchable to a super pivot position corresponding to the pivot turn state, and the control device 64 corresponds to the pivot mode selected according to the operation position of the pivot mode switch 78. The turning state of the travel drive means 100 is switched by setting the to the on state.

  When the turning lever 77 is operated to the rectilinear command position N, the right and left turning control valves 67 and 68 are operated to the discharge positions 67b and 68b, the unload valve 70 is operated to the discharge position 70b, and the right and left The hydraulic oil is discharged from the side clutch 34 and the right and left turning clutch 49, the right and left side clutch 34 are operated to the transmission state, and the right and left turning clutch 49 are operated to the half transmission state. Since the right and left turning control valves 67 and 68 are operated to the discharge positions 67b and 68b and the unload valve 70 is operated to the discharge position 70b, the hydraulic oil from the hydraulic pump 56 passes to the transmission case 10 through the unload valve 70. Returned.

  As a result, the power of the input shaft 22 is transmitted to the sub-transmission transmission shaft 27, the transmission gears 30, 31, the linear transmission transmission shaft 29, the right and left side clutches 34 (the right and left occlusion portions 33R, 33L), the right and The aircraft is transmitted straight to the right and left crawler travel devices 1 via the left output gears 32R and 32L, the transmission gear 36, the transmission shaft 35, the transmission gears 37 and 39, and the right and left axles 38.

Next, the case where the turning lever 77 is operated to the turning command operation area when the turning mode switch 78 is operated to the slow turning position will be described.
When the turning mode switch 78 is operated to the slow turning position and the turning lever 77 is operated to the right from the straight command position N to move out of the dead zone, the right turning control valve 67 is operated to the supply position 67a to unload. The valve 70 is switched to the shut-off position 70a, hydraulic oil is supplied to the right side clutch 34 (right occlusion portion 33R) and the right turning clutch 49, and the right side clutch 34 (right occlusion portion 33R) is shut off. The hydraulic oil is supplied to the right turning clutch 49 and is operated to the transmission state.

  In this case, since the left turning clutch 49 is in a semi-transmission state, the power of the left side clutch 34 is transmitted from the left output gear 32L and the left turning clutch 49 to the right output gear 32R via the right turning clutch 49. The power slightly lower than that of the linear transmission shaft 29 is transmitted to the right output gear 32R by rotation in the same direction as the linear transmission shaft 29. As a result, the aircraft gently turns to the right.

  When the swivel lever 77 is operated rightward from the rectilinear command position N and moves out of the dead zone, the proportional control valve 71 and swivel switching are almost simultaneously with the right swivel control valve 67 being operated to the supply position 67a as described above. The hydraulic oil begins to be supplied to the slow swing clutch 46 via the control valve 72, and as the swing lever 77 is moved to the right in a direction away from the straight advance command position after moving out of the dead zone, the proportional control valve 71 becomes slower. The operation pressure of the swing clutch 46 is increased.

  As the operation pressure of the slow swing clutch 46 is increased by the proportional control valve 71 based on the operation position of the swing lever 77, the power of the straight drive shaft 29 is changed to the right occlusal portion 33R, the transmission gear 45, Through the turning clutch 46, the transmission shaft 44, the transmission gear 48, the turning clutch case 47 and the right turning clutch 49, the motive power at a lower speed than the straight traveling transmission shaft 29 is rotated in the same direction as the straight traveling transmission shaft 29. It is transmitted to the output gear 32R.

  In this case, the power from the left side clutch 34 (the left occlusal portion 33L) and the power from the slow turning clutch 46 are transmitted to the right output gear 32R at the same time. In the range where the operation pressure is low, the power from the left side clutch 34 (the left occlusion portion 33L) overcomes the power from the slow swing clutch 46, and the power from the left side clutch 34 (the left occlusion portion 33L). As a result, the right output gear 32R is driven. As a result, when the operating pressure of the gentle turning clutch 46 is low, the aircraft gradually turns to the right.

  When the amount of movement of the turning lever 77 to the right increases and the operating pressure of the slow turning clutch 46 increases, the power from the slow turning clutch 46 overcomes the power from the left side clutch 34 (left occlusal portion 33L). Thus, the right output gear 32R is driven by the power from the slow turning clutch 46. In this state, the right output gear is driven by the power from the slow turning clutch 46 rather than the left output gear 32L driven by the power of the straight transmission shaft 29 via the left side clutch 34 (the left engagement portion 33L). 32R will be driven at low speed and the aircraft will turn slowly to the right. The turning state at this time corresponds to a low-speed turning turning state in which the traveling device inside the turning rotates at a lower speed than the traveling device outside the turning in the airframe traveling direction.

  When the swivel lever 77 is operated to the left from the rectilinear command position N and moves out of the dead zone, the left swivel control valve 68 is operated to the supply position 68a, the unload valve 70 is held at the shut-off position 70a, and the left side The hydraulic oil is supplied to the clutch 34 (the left occlusion portion 33L) and the left turning clutch 49, the left side clutch 34 (the left occlusion portion 33L) is operated to be disconnected, and the left turning clutch 49 is operated with the hydraulic oil. Is operated in the transmission state. At the same time, the same operation as the left turn described above is performed, and the aircraft gradually turns to the left. Further, when the operation amount to the right side of the turning lever 77 increases and the operation pressure of the slow turning clutch 46 becomes high, the same operation as the right turning operation is performed, and the aircraft turns slowly to the left.

Next, the case where the turning lever 77 is operated to the turning command operation area when the turning mode switch 78 is operated to the conviction turning position will be described.
When the turning mode switch 78 is operated to the cruciform turning position and the turning lever 77 is operated rightward from the rectilinear command position N to move out of the dead zone, the right turning control valve 67 is operated to the supply position 67a to unload. The valve 70 is switched to the shut-off position 70a, hydraulic oil is supplied to the right side clutch 34 (right occlusion portion 33R) and the right turning clutch 49, and the right side clutch 34 (right occlusion portion 33R) is shut off. The hydraulic oil is operated to the right turning clutch 49 in the transmission state. In this case, since the left turning clutch 49 is in a semi-transmission state, the aircraft gradually turns to the right.

  When the swivel lever 77 is operated rightward from the rectilinear command position N and moves out of the dead zone, the proportional control valve 71 and swivel switching are almost simultaneously with the right swivel control valve 67 being operated to the supply position 67a as described above. The hydraulic oil begins to be supplied to the reverse rotation clutch 53 via the control valve 72 (super pivot turning position 72c), and the turning lever 77 is moved to the right in the direction away from the dead reckoning command position after leaving the dead zone. The proportional control valve 71 increases the operating pressure of the reverse clutch 53. However, even if the turning lever 77 is operated rightward to the maximum operation position Rm at this time, the operation pressure of the reverse clutch 53 does not reverse the transmission shaft 44 but stops the rotation of the transmission shaft 44 or substantially. The operating pressure is adjusted so as to stop.

  In this case, the power from the left side clutch 34 (left occlusal portion 33L) and the braking force of the transmission shaft 44 braked via the reverse clutch 53 are simultaneously transmitted to the right output gear 32R. Therefore, in the range where the operating pressure of the reverse clutch 53 is low, the power from the left side clutch 34 (left occlusion portion 33L) overcomes the braking force of the reverse clutch 53 and the left side clutch 34 (left occlusion) The right output gear 32R is driven by the power from the portion 33L). As a result, when the operating pressure of the reverse clutch 53 is in a low pressure range, the aircraft gradually turns to the right.

  When the amount of movement of the swivel lever 77 to the right increases and the operating pressure of the reverse clutch 53 reaches an operating pressure set to act as a brake, the braking force is applied to the left side clutch 34 (the left occlusal portion 33L). ), The right output gear 32R enters the braking state, and the aircraft turns to the right. The turning state at this time corresponds to a stopped turning state in which the rotation of the traveling device inside the turning is stopped or substantially stopped.

  Accordingly, as the operation pressure of the reverse clutch 53 is increased by the proportional control valve 71 in accordance with the operation of the turning lever 77, the transmission shaft 44, the transmission gear 48, the turning clutch case 47, and the right turning clutch 49 are moved. Thus, a braking force is applied to the right output gear 32R. That is, the pseudo brake state is equal to the state in which the transmission shaft 44 is braked by the brake.

  When the turning lever 77 is operated to the left from the rectilinear command position N to move out of the dead zone, the left turning control valve 68 is operated to the supply position 68a, the unload valve 70 is operated to the cutoff position 70a, and the left side clutch 34 (the left occlusion portion 33L) and the left turning clutch 49 are supplied with hydraulic oil, the left side clutch 34 (the left occlusion portion 33L) is operated to be disconnected, and the left turning clutch 49 is supplied with hydraulic oil. Operated in transmission state. At the same time, the same operation as described above is performed, and the aircraft gradually turns to the left. When the amount of movement of the turning lever 77 to the left increases and the operating pressure of the reverse clutch 52 becomes high, the same operation as the right turning operation is performed, and the aircraft turns to the left.

Next, the case where the turning lever 77 is operated to the turning command operation area when the turning mode switch 78 is operated to the super turning position will be described.
When the turning mode switch 78 is operated to the super turning position, and the turning lever 77 is operated rightward from the straight travel command position N to move out of the dead zone, the right turning control valve 67 is operated to the supply position 67a and The load valve 70 is switched to the shut-off position 70a, hydraulic oil is supplied to the right side clutch 34 (right occlusion portion 33R) and the right turning clutch 49, and the right side clutch 34 (right occlusion portion 33R) is moved. The shut-off state is operated, and the right turning clutch 49 is operated in the transmission state. In this case, since the left turning clutch 49 is in a semi-transmission state, the aircraft gradually turns to the right.

  When the swivel lever 77 is operated rightward from the rectilinear command position N and moves out of the dead zone, the proportional control valve 71 and swivel switching are almost simultaneously with the right swivel control valve 67 being operated to the supply position 67a as described above. The hydraulic oil starts to be supplied to the reverse rotation clutch 53 via the control valve 72 (super pivot turning position 72c), and the proportional control valve is moved as the turning lever 77 moves to the right side out of the dead zone from the straight advance command position. 71 increases the operating pressure of the reverse clutch 53. When the turning lever 77 is operated to the maximum operating position Rm in the right direction in this super turning state, the operating pressure of the reverse clutch 53 causes the reverse rotation clutch 53 to be fully engaged and the transmission shaft 44 to go straight. Adjustment is made to rotate in the direction opposite to the axis 29.

  As the operation pressure of the reverse clutch 53 is increased by the proportional control valve 71 in accordance with the operation of the turning lever 77, the power of the subtransmission transmission shaft 27 is transmitted to the transmission gears 51, 52, the reverse clutch 53, the transmission shaft. 44, the transmission gear 48, the turning clutch case 47, and the right turning clutch 49 are transmitted to the right output gear 32R as the rotational power in the direction opposite to that of the straight drive shaft 29.

  In this case, since the power from the left side clutch 34 (the left occlusal portion 33L) and the power from the reverse clutch 53 are simultaneously transmitted to the right output gear 32R, the operation pressure of the reverse clutch 53 is reached. In the low pressure range, the power from the left side clutch 34 (the left occlusion portion 33L) overcomes the power from the reverse clutch 53, and the power from the left side clutch 34 (the left occlusion portion 33L) The output gear 32R is driven. As a result, when the operating pressure of the reverse clutch 53 is in a low pressure range, the aircraft gradually turns to the right.

  Then, when the amount of movement of the turning lever 77 to the right increases and the operating pressure of the reverse clutch 53 becomes high, the power from the reverse clutch 53 becomes the power from the left side clutch 34 (the left occlusal portion 33L). The right output gear 32R is driven by the power from the reverse clutch 53 by overcoming it. In this state, the right output gear 32R is driven in the opposite direction with respect to the left output gear 32L, and the aircraft turns to the right. The turning state at this time corresponds to a sudden turning state in which the traveling device inside the turning is driven so as to travel in the direction opposite to the aircraft traveling direction.

  Next, when the turning lever 77 is operated leftward from the rectilinear command position N, when the dead zone is removed, the left turning control valve 68 is operated to the supply position 68a, and the unload valve 70 is moved to the cutoff position 70a. The hydraulic oil is supplied to the left side clutch 34 (left occlusion portion 33L) and the left turning clutch 49, and the left side clutch 34 (left occlusion portion 33L) is operated to be disconnected, The hydraulic oil is operated in the transmission state to the swing clutch 49. At the same time, the same operation as described above is performed, and the aircraft gradually turns to the left. When the amount of operation for moving the turning lever 77 to the left increases and the operating pressure of the reverse clutch 53 becomes high, the same operation as in the case of right turning is performed, and the aircraft turns to the left.

  By the way, when the turning mode switch 78 is operated to the slow turning position and turning in the slow turning mode, or the turning mode switch 78 is operated to the trust turning position, the turning in the trust turning state is performed. When performing, in a turning state in which the turning lever 77 is operated rightward or leftward beyond the dead zone, it may be necessary to turn with a slightly smaller radius.

  Therefore, in this combine, as shown in FIG. 5, a turning state changeover switch 81 is provided at the grip portion of the turning lever 77. For example, in the slow turning mode, if the turning state changeover switch 81 is pressed while the turning lever 77 is operated to turn, the turning switching control valve 72 changes from the slow turning position 72a to the super turning position 72b. Can be switched to the belief turning state as described above. This belief turning state is only while the turning state changeover switch 81 of the turning lever 77 is pushed and operated. When the turning state release switch 81 of the turning lever 77 is released and returned, the turning changeover control valve 72 is turned on. The fuselage is operated from the pivot turn position 72b to the slow turn position 72a, and the aircraft returns to the slow turn state.

  Further, in the case of the pivoting state, if the turning state changeover switch 81 of the turning lever 77 is pushed and operated while the turning lever 77 is operated, the operation pressure to the reverse clutch 53 is changed and adjusted. The turning position of the turning lever 77 is reached. The turning position of the turning lever 77 is only while the turning state changeover switch 81 of the turning lever 77 is being pressed. When the return switch 81 is released by releasing the hand, the vehicle returns to the pivoting state and returns to the gentle turning state.

  Therefore, in this embodiment, the turning mode switch 78 and the turning state changeover switch 81 correspond to the turning state selection means.

Next, the contents of control by the control device 64 will be described.
In the state where the turning drive state is selected by the steering command means 200 and an operation pressure greater than a preset set operation pressure is instructed, the control device 64 includes a turning mode switch 78 as a turning state selection means and When another turning state is selected by the turning state changeover switch 81, specifically, when switching from the gentle turning state to the trust turning state, and when switching from the slow turning state to the super trust turning state. Is changed so that the operating pressure is lower than the operating pressure commanded at that time, and then the frictional hydraulic clutch M is switched to the disengaged state and the friction type corresponding to the other turning state. The hydraulic clutch M is switched to the engaged state, and then the proportional control valve 7 is set so that the operating pressure of the friction hydraulic clutch M becomes the operating pressure commanded by the steering command means 200. It is configured to control the.

  Further, the control device 64, based on a command from the steering command means 200, uses a turning mode switch 78 as a turning state selection means using the operating pressure when the maximum target value is commanded as the operating pressure of the friction hydraulic clutch M, and The proportional control valve 71 is operated so that the operation pressure corresponding to the turning state selected by the turning state changeover switch 81 is adjusted so as to increase as a large target value is commanded.

  That is, the control device 64 moves the relationship between the operation position and the target operation pressure in the turning command operation area of the turning lever 77 constituting the steering command means 200 in a direction away from the straight command position in the turning command operation area. The unit amount of the operation position of the turning lever 77 increases as the amount increases, and as the amount of movement in the direction away from the rectilinear command position in the turning command operation region increases over the entire range of the turning command operation region. A direction corresponding to a quadratic function that changes the amount of change in the target operation pressure with respect to a change to the large side, and a direction away from the straight command position in the turning command operation region defined as a relationship corresponding to the quadratic function Based on the relationship between the amount of movement to the target operating pressure and the operating position of the turning lever 77, the operating position of the turning lever 77 Seeking a target operating pressure to respond, and is configured to control the proportional control valve so that the target operating pressures.

  As shown in FIG. 6, as the three types of turning states, in the slow turning state, when the turning lever 77 is operated to the maximum operation position, the output rotation of the traveling device inside the turning of the pair of left and right traveling devices. A target turning state is set in which the speed is reduced to about 1/3 of the output rotational speed of the opposite side traveling device (see line L1 in FIG. 6). The target speed ratio is set so that the output rotational speed of the vehicle is zero (see the line L2 in FIG. 6). In the super turning state, the output rotational speed of the traveling device on the inner side of the turn is the driving rotational direction of the traveling device on the opposite side. A target speed ratio is set such that the speed is approximately 1/3 of the output rotational speed of the opposite traveling device in the reverse rotation direction (see line L3 in FIG. 6).

  Then, as shown in FIG. 7, the operation position of the turning lever 77 and the target operation pressure (specifically, proportional control) of the friction hydraulic clutch M so that the target speed ratio as described above is obtained in advance through experiments or the like. The target current supplied to the valve 71 is determined as a relationship corresponding to a quadratic function that changes the amount of change in the target operating pressure of the friction hydraulic clutch M with respect to the change per unit amount of the operating position. And stored in the control device 64.

When setting the target current, the control device 64 switches the target value commanded by the steering command means 200 when it is switched from the pivot turn state to the super trust state. The value is configured to increase under the setting increase condition.
In other words, a line L4 in FIG. 7 indicates an operation position of the turning lever 77 and a target operating pressure of the friction hydraulic clutch M (target current supplied to the proportional control valve 71) in the slow turning state and the super turning state. The line L5 in FIG. 7 shows the relationship between the operating position of the turning lever 77 and the target operating pressure of the friction hydraulic clutch M (target current supplied to the proportional control valve 71) in the pivoting state. Correlation is shown. In this line L4, when the turning lever 77 is operated to the maximum operating positions Lm, Rm, the slow turning clutch 46 is operated to a fully engaged state by a strong pressure contact force in the case of the slow turning state. In the case of the pivoting state, the operation pressure is set such that the reverse rotation clutch 53 is operated to a complete engagement state with a strong pressure contact force. However, in the line L5, when the turning lever 77 is operated to the maximum operating positions Lm and Rm, the transmission shaft 44 is not driven in reverse rotation, but the turning of the traveling device 1 inside the turning is stopped or substantially stopped. The operating pressure is set so as to be in a state.

  The target operating pressure indicated by the line L4 is set to an operating pressure corresponding to the maximum opening when the target value commanded by the steering command means 200 is the maximum target value. When the target value commanded at is not the maximum target value, the target value is increased under the setting increase condition. Specifically, the target value in the bend turning state indicated by the line L5 is set to a set ratio ( An increased value is set (about 25%).

  Further, the control device 64 operates the proportional control valve 71 so that the operation pressure adjusted with respect to the target value commanded by the steering command means 200 is repeatedly changed by a set amount as time elapses. It is configured.

Hereinafter, the turning control of the control device 64 will be described with reference to the flowcharts shown in FIGS.
If the turning lever 77 is within the dead zone of the straight travel command position N, the unload valve 70 is switched to the discharge position 70a (steps 1 and 2). Further, both the left turn control valve 68 and the right turn control valve 67 are kept in the shut-off state (steps 3 and 4). When the turning lever 77 deviates from the dead zone from the straight travel command position N, the left turn control valve 68 is switched to the supply position 68a if the operation direction is the left direction, and the right turn control valve 67 is turned if the operation direction is the right direction. Switching to the supply position 67a (steps 5, 6, 7), the unload valve 70 is switched to the shut-off position 70a (step 8).

  When the turning lever 77 is operated in the turning operation area and the vehicle is turning, if switching of the turning state by the operation of the turning state switch 81 or the turning mode switch 78 is not instructed, Based on the correlation shown in FIG. 7 corresponding to the swing mode selected by the swing mode switch 78 and the detection information of the swing lever sensor 80, the target current for the proportional control valve 71 is obtained by calculation, and the swing lever If 77 is not operated in the vicinity of the maximum operation position (Rm, Lm), a proportional valve operation process for supplying a target current to the proportional control valve 71 is executed (steps 14, 15, 16).

In this proportional valve operation process, as shown in FIG. 12, the output current is adjusted so that the output current output to the proportional control valve 71 becomes the target current obtained by calculation (steps 100 and 101). Thus, by adjusting the output current in the feedforward process, a desired turning force corresponding to the operation position of the turning lever 77 can be obtained with as little time delay as possible.
Moreover, in this proportional valve actuation process, the proportional control valve 71 is operated so that the operating pressure to be adjusted with respect to the target value commanded by the steering command means 200 is repeatedly changed over time. In this way, by repeatedly generating a large fluctuation in the operation pressure for the friction hydraulic clutch M, for example, the driving state of the traveling device 1 that receives driving resistance such as traveling resistance from the road surface can be changed to a desired turning state. The driving state corresponding to can be switched as smoothly as possible.

  Then, when the turning lever 77 is operated in the turning operation area and the vehicle is turning, the turning state is switched by the operation of the turning state switch 81 or the switching operation of the turning mode switch 78, and at that time If the turning lever 77 is operated to the operation position corresponding to the larger target turning force larger than the preset turning force set in advance and the turning is commanded, the turning lever 77 corresponds to the target turning force. After executing the operation pressure reduction process for reducing the operation pressure so that the operation pressure is reduced to be smaller than the target operation pressure, the turning state switching process is executed (steps 9, 10, 11, 12).

  That is, in the operation pressure reduction process, as shown in FIG. 13, a low-side target current lower than the current target current calculated in a state corresponding to the operation position of the turning lever 77 is obtained, and the proportional control valve 71 is supplied. The output current is adjusted so that the output current becomes the lower target current (steps 201, 202, 203). After the output current to the proportional control valve 71 becomes the low-side target current, a turning state switching process for changing to the turning state corresponding to the turning state for which switching has been commanded is performed (step 12).

  By the way, as the turning state switching process, when the trust turning state or the super turning state is selected from the slow turning state, the turning switch control valve 72 is super Switching to the ground turning position 72c, but when switching from the pivot turn state to the super pivot turn state, instead of switching the turn switching control valve 72, the adjustment of the operation pressure to the reverse clutch 53 is performed based on the line L5. The state to be adjusted is switched to the state to be adjusted based on the line L4.

  A specific example will be described with reference to FIG. 8 and FIG. 9. For example, if the slow turning state is before switching and the super turning state is after switching, the turning lever 77 is at the maximum operating position in the slow turning state. From the state of operation (position of point a), while maintaining the turning state in the slow turning state, the operating pressure of the slow turning clutch 46 is lowered to the position indicated by point b in the figure, and then the turning switching control valve. 72 is switched from the slow turning position 72a to the super turning position 72c (the position of the point c), and then electrically controlled so as to increase the operating pressure of the reverse clutch 53 to the position of the point d. The operation position of the turning lever 77 is maintained at the same maximum operation position. Further, as shown in FIG. 10, the same applies even when the vehicle is in the gentle turning state before switching and in the belief turning state after switching.

[Second Embodiment]
Next, a second embodiment of the turning control device for a work vehicle according to the present invention will be described. In this embodiment, the configuration of the frictional hydraulic clutch M in the travel drive means, the hydraulic circuit configuration for driving the frictional hydraulic clutch M, the operating position of the turning lever for adjusting the operating pressure of the frictional hydraulic clutch M, the target operating pressure, Except for the difference in the correlation and the configuration of the control process, the configuration is the same as the configuration of the first embodiment.

  In other words, in the second embodiment, the traveling drive means 100 is transmitted to the traveling device inside the turning of the pair of left and right traveling devices 1 as the plurality of turning states in the turning drive state. By changing the magnitude of the propulsive force traveling in the direction opposite to the direction by the friction type hydraulic clutch M, the sudden turning state, the stop turning state, and the traveling device inside the turning are turned outward in the aircraft traveling direction. Is switched to a low-speed rotation turning state that rotates at a lower speed than the traveling device, and the control device 64 as the operation control means is based on a command from the selection state selection means in the turning drive state. The operating pressure of the frictional hydraulic clutch M is set to a sudden turning operation pressure corresponding to the sudden turning state, a stopping turning operation pressure corresponding to the previous stop turning state, and the low speed rotation turning. To adjust the low speed rotation operation pressure corresponding to the state, it is configured to operate the proportional control valve 71 as the supply pressure adjusting means.

  Specifically, as shown in FIG. 14, as the friction hydraulic clutch M, only the reverse clutch 53 in the first embodiment is provided, and the slow swing clutch 46 in the first embodiment is deleted. It has become. Further, as shown in FIGS. 15 and 16, since the slow turning clutch 46 is eliminated, a flow path switching configuration is unnecessary, and therefore, the turning switching control valve 72 and the super pivot turning pilot in the hydraulic unit 57 are eliminated. The valve 74 is omitted. The driving state of the traveling device on the inner side of the turn is changed by adjusting the operation pressure of the reverse rotation clutch 53 in each of the gentle turn state, the belief turn state, and the super turn turn.

  That is, as shown in FIG. 17, a slow turning state is established as a correlation between the operation position of the turning lever 77 and the target operating pressure (target current supplied to the proportional control valve 71) of the friction hydraulic clutch M (reverse clutch 53). The three types of lines L4 to L6 corresponding to each of the belief turning state and the super belief turn are set.

In the super-revolution turning line L 4 , the operation pressure is set such that the reverse clutch 53 is fully engaged when the turning lever 77 is operated to the maximum operating positions Lm and Rm. In the belief turning line L5, when the turning lever 77 is operated to the maximum operating positions Lm and Rm, the transmission shaft 44 is not driven in reverse rotation, but the turning of the traveling device inside the turning is stopped or substantially omitted. The operating pressure is set so that the braking state is stopped. Then, slow in line L 6 for turning up the operating position the pivoting lever 77 Lm, when operated to the Rm, the traveling device of the turning inner swivel clutch rotational power for straight is in a semi-transmission state 49, a rotational operation force transmitted in the forward direction through 49 and a braking force that allows rotation in the forward direction due to the accompanying contact with the ground are applied, resulting in a pseudo slow turning state. The operating pressure is set.

  Therefore, in this combine, each of the turning states of the gentle turning state, the belief turning state, and the super-belief turning state can be revealed using one friction type hydraulic clutch.

[Another embodiment]
Hereinafter, other embodiments are listed.

(1) In the above embodiment, the relation corresponding to the quadratic function that changes the change amount of the target operation pressure to the large side with respect to the change per unit amount of the operation position of the steering command means is described. It may have a linearly changing correspondence relationship, and is not limited to one in which the steering command means is configured to command a target operation pressure that increases as the distance from the straight command position increases. Then, a predetermined operation pressure set in advance may be commanded.

(2) In the above embodiment, the turning mode switch 78 and the turning state changeover switch 81 as the turning state selection means and the steering command means 200 are separately provided. However, the invention is not limited to such a structure. The steering command means may also be used as the turning state selection means. In other words, the turning lever that constitutes the steering command means switches to a state in which turning is commanded from the straight-ahead command position, and sequentially switches to the gentle turning state, the trust turning state, and the super trust turning state as the operation amount increases. It is good also as a structure which switches a turning state so that it may change.

(3) In the above embodiment, the turning state selection switch is provided with a turning state changeover switch in a state where a finger can be operated on the grip portion of the turning lever. However, such a turning state changeover switch is not provided. Also good.

(4) In the above embodiment, the steering command means includes a swing lever that can be moved and operated over the straight command position and the swing command operation area. For example, a rotary operation dial or a plurality of push-operated switches It can implement with various forms, such as a structure provided with.

(5) In the above embodiment, the combine is shown as the work vehicle. However, the present invention can also be applied to agricultural work vehicles other than the combine vehicle and other work vehicles.

Overall side view Diagram showing transmission configuration Diagram showing transmission configuration Hydraulic circuit diagram Control block diagram The figure which shows the correlation between the turning lever operation position and the target speed ratio The figure which shows the correlation between the turning lever operation position and the target operation pressure Explanatory drawing showing the switching state of the turning state Explanatory drawing showing the switching state of the turning state Explanatory drawing showing the switching state of the turning state Flow chart of control operation Flow chart of control operation Flow chart of control operation Diagram showing transmission configuration Hydraulic circuit diagram Control block diagram The figure which shows the correlation between the turning lever operation position and the target operation pressure

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Traveling apparatus 64 Operation control means 71 Supply pressure adjustment means 78, 81 Turning state selection means 100 Travel drive means 200 Steering command means M Friction type hydraulic clutch

Claims (5)

Drive the driving state of the pair of left and right traveling devices at the same speed, drive the both sides at the same speed, and drive the outer one of them in the direction of the aircraft, and reduce the propulsive force of the inner side of the turning in the direction of the aircraft Traveling drive means comprising a hydraulically operated frictional hydraulic clutch that is switchable to a swing drive state and that switches to a plurality of swing states in the swing drive state;
Supply pressure adjusting means for changing and adjusting the supply pressure of the pressure oil supplied from the hydraulic source to the friction type hydraulic clutch;
A turning state selection means for selecting one of the plurality of turning states;
Steering command means for selecting the straight traveling state and the turning drive state;
A working vehicle turning control device provided with operation control means for operating the travel driving means and the supply pressure adjusting means based on commands of the turning state selection means and the steering command means,
The traveling driving means has a large propulsive force that travels in a direction opposite to the traveling direction of the airframe transmitted to the traveling device inside the turning of the pair of left and right traveling devices as the plurality of turning states in the turning driving state. By changing the length with the friction type hydraulic clutch, the sudden turning state in which the traveling device inside the turn is driven to advance in the direction opposite to the aircraft traveling direction and the rotation of the traveling device inside the turn are stopped or substantially stopped. Configured to switch to a stop turning state to
In the turning drive state, the operation control means responds to the sudden turning operation pressure corresponding to the sudden turning state and the stop turning state based on the command of the turning state selection means. Configured to operate the supply pressure adjusting means in order to adjust to the stop turning operation pressure .
When the operation control means is switched from the stop turning state to the sudden turning state by the turning state selection means, and the target value commanded by the steering command means is not the maximum target value, the target A work vehicle turning control device configured to increase a value under a setting increase condition . The traveling driving means has a large propulsive force that travels in a direction opposite to the traveling direction of the airframe transmitted to the traveling device inside the turning of the pair of left and right traveling devices as the plurality of turning states in the turning driving state. By changing the height with the friction type hydraulic clutch, the sudden turning state, the stop turning state, and the low speed at which the traveling device inside the turning rotates at a lower speed than the traveling device outside the turn in the aircraft traveling direction. It is configured to switch to a turning state,
In the turning driving state, the operation control means responds to the sudden turning operation pressure corresponding to the sudden turning state and the pre-stop turning state based on the command of the selection state selecting means. 2. The work vehicle according to claim 1, wherein the supply pressure adjusting means is operated so as to be adjusted to a stop turning operation pressure and a low speed rotation turning operation pressure corresponding to the low speed rotation turning state. Swivel control device.   The turning control device for a work vehicle according to claim 1 or 2, wherein the supply pressure adjusting means is configured to change and adjust an opening degree of an oil passage through which the pressure oil is supplied to the frictional hydraulic clutch. The steering command means is configured to continuously command a target value between a minimum target value and a maximum target value;
The turning state in which the operation control means has selected the operation pressure when the maximum target value is instructed as the operation pressure of the friction hydraulic clutch based on the instruction of the steering instruction means by the turning state selection means 4. The apparatus according to claim 1, wherein the supply pressure adjusting unit is configured to operate so as to be adjusted so that a larger target value is commanded in a state in which the operation pressure corresponds to. Slewing control device for work vehicles. The operation control means is configured to operate the supply pressure adjustment means so that the operation pressure to be adjusted with respect to the target value commanded by the steering command means is repeatedly changed by a set amount with time. The turning control device for a work vehicle according to claim 4.

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