JP5377864B2 - Work vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a working vehicle, provided with a travel part driven by use of engine output, in which a brake turn is effectively performed to stop the travel part on the turning side regardless of a car speed range. <P>SOLUTION: In a case of a high speed output state where an HST 102 cannot put corresponding travel parts 40L and 40R to a stop state even with the maximum output of electric motors 33L and 33R for turning, when turning operation members 56L and 56R are operated, a control device 270 performs, instead of a normal control mode, reduction control to put the output rotation number of the HST 102 at a reference rotation number Sm with which the rotation number of the corresponding travel parts 40L and 40R can be zero or less with the maximum output of the electric motors 33L and 33R for turning as the operation members 56L and 56R are operated from a non-operation position to the maximum operation position, while performing brake turn control to perform output control to the electric motors 33L and 33R for turning in accordance with operation quantity of the operation members 56L and 56R for turning. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a work vehicle such as a snowplow.

  A working vehicle such as a snowplow having a traveling HST that is operatively driven by an engine is known (see, for example, Patent Document 1).

In such a working vehicle, a pair of left and right differential mechanisms synthesize a traveling rotational power input from a traveling mechanism including a traveling HST and a braking rotational power input from a swinging mechanism including a swing motor. There are some which are configured to output respectively to the traveling section.
Specifically, it has a pair of left and right turning electric motors that can be driven by the electric power of the battery charged by the engine, and the driving force of the pair of left and right turning electric motors applied to the rotation output of the traveling HST is changed to the left and right. By making it different, the driving force to the pair of left and right traveling parts is made different, and the snowplow is turned left or right.
In such a working vehicle, by maximizing the rotation speed of the turning electric motor on the turning side, the running part on the turning side is stopped and the driving force of the running part opposite to the turning side is used. A turning turn can be performed, and the turning radius can be reduced.

Here, in order to prevent the load of the turning electric motor from becoming excessive with respect to the output rotation speed of the traveling HST, the rotation speed of the turning electric motor is limited to a predetermined rotation speed or less.
For this reason, when the rotational speed of the electric motor for turning is maximized at a predetermined vehicle speed or higher (the output rotational speed of the traveling HST is equal to or higher than the predetermined rotational speed), the speed of the traveling section does not become zero.
That is, there is a problem in that a brake turn cannot be performed even if the rotation speed of the turning electric motor on the turning side is maximized at a predetermined vehicle speed or more, and the turning radius becomes large.
JP-A-7-173810

  The present invention has been made in view of the above-described prior art, and is a working vehicle including a traveling unit that is driven using an output from an engine, and stops the traveling unit on the turning side regardless of the vehicle speed range. An object is to provide a working vehicle capable of effectively performing a brake turn.

In order to achieve the above object, in the work vehicle according to the present invention, a pair of left and right differential mechanisms are input from a traveling rotational power input from a traveling mechanism including a traveling HST and a turning mechanism including a pair of left and right turning motors. The brake rotation power is combined and output to the pair of left and right traveling units, and the control device of the control mechanism operates in the normal control mode with the operation amount of the traveling operation member and the pair of left and right turning operation members. The control device is configured to control the output of the traveling HST and the pair of left and right turning motors according to the control unit, and the control device includes a traveling unit corresponding to the traveling HST by the maximum output of the turning motor. If the turning operation member is operated in a high-speed output state that cannot be stopped, brake turn control is executed instead of the normal control mode. Is configured, the brake-turn control, the when one is operated in the left and right rotation operation member, the pivot operation member is the maximum operation position and the output rotation speed of the traveling HST in the operation immediately before the turning operation member Based on the reference rotational speed of the traveling HST set so that the rotational speed of the corresponding traveling section is set to 0 or less by the maximum output of the swing motor when the rotational operation is performed. A turning control function related to the target output rotation speed of the traveling HST is calculated, and the traveling HST is set to a target output rotation speed calculated based on the turning control function and an operation amount of the turning operation member. performs deceleration control, the have line output control of the swing motor in accordance with the operation amount of the rotation operation member, and, both of the pair of left and right swing operation member When it is made, in addition to the turning control function, based on the output rotation speed of the traveling HST just before the operation of the turning operation member and the output rotation speed of the traveling HST that stops the pair of traveling portions, A braking control function relating to the target output rotation speed of the travel HST with respect to the operation amount of the turning operation member is calculated, and the travel HST corresponding to each of the operation amounts of the pair of left and right turning operation members is calculated based on the turning control function. The first and second target rotation speeds are calculated, and the third target rotation speed of the travel HST corresponding to the smaller operation amount of the operation amounts of the pair of left and right turning operation members is calculated based on the braking control function. And controlling the output rotational speed of the travel HST so that the lowest rotational speed among the first, second and third target rotational speeds is set as the target rotational speed. Both control the output of the swing motor according to the operation amount of each of the pair of left and right turning operation members, and when both the pair of left and right turning operation members are operated to the maximum operation position, the control device, Instead of the normal control mode and the brake turn control, the output rotational speed of the traveling HST is controlled to an output that stops the pair of traveling units .

According to the work vehicle having the above-described configuration, the traveling HST of the traveling mechanism and the pair of left and right turning motors of the turning mechanism are operated by operating the traveling operation member and the pair of left and right turning operation members in the normal control mode of the control device. Controlled according to quantity.
Here, when the turning operation member is operated when the traveling HST is in a high-speed output state in which the corresponding traveling unit cannot be stopped even by the maximum output of the turning motor, the control device performs brake turn control. Migrate to
In brake turn control, when one of the pair of left and right turning operation members is operated, the control device operates the output rotation speed of the traveling HST immediately before the operation of the turning operation member and the turning operation member to the maximum operation position. The traveling with respect to the operation amount of the turning operation member based on the reference rotation speed of the traveling HST set so that the rotation speed of the corresponding traveling unit is set to 0 or less by the maximum output of the turning motor when A turning control function related to the target output rotational speed of the HST is calculated, and the traveling HST is decelerated and controlled so that the traveling HST becomes a target output rotational speed calculated based on the turning control function and the operation amount of the turning operation member. To do. In addition, the control device controls the output of the turning motor in accordance with the operation amount of the turning operation member.

Thus, when the running HST is one operation of the pair of left and right swing operation member travel section if the high-speed output state can not be a stop state to cope with the maximum output of the swing motor, the By performing the control for decelerating the traveling HST based on the turning control function, the brake turn (turning side traveling unit stop) is always possible if the turning operation member is operated to the maximum amount. But the turning radius can be reduced.

In the brake turn control, when both of the pair of left and right turning operation members are operated, the control device, in addition to the turning control function, outputs the rotation speed of the traveling HST immediately before the operation of the turning operation member and the pair of turning operations. A braking control function relating to the target output rotational speed of the traveling HST with respect to the operation amount of the turning operation member is calculated based on the output rotational speed of the traveling HST that stops the traveling portion of the traveling portion, and based on the turning control function, the braking control function is calculated. The first and second target rotational speeds of the travel HST corresponding to the operation amounts of the pair of left and right turning operation members are calculated, and among the operation amounts of the pair of left and right turning operation members based on the braking control function The third target rotational speed of the travel HST corresponding to the smaller operation amount is calculated, and the smallest rotational speed among the first, second and third target rotational speeds is targeted. It controls the output speed of the running HST so that the target rotational speed as the rolling speed, performs the output control of the swing motor in accordance with respective operation amounts of the pair of left and right swing operation member.

In this case, in the brake turn control (high-speed output state), when both the pair of left and right turning operation members are operated, the control device firstly adds the turning control function and immediately before the operation of the turning operation member. Based on the output rotational speed of the traveling HST and the output rotational speed of the traveling HST that stops the pair of traveling units, a braking control function related to the target output rotational speed of the traveling HST with respect to the operation amount of the turning operation member is calculated. . Subsequently, the control device calculates the first and second target rotational speeds of the traveling HST corresponding to the operation amounts of the left and right turning operation members by the calculated turning control function, and calculates the calculated braking control function. To calculate the third target rotational speed of the traveling HST corresponding to the smaller operation amount of the operation amounts of the pair of left and right turning operation members.
Then, the control device sets the smallest rotation speed among the first, second and third target rotation speeds as the target rotation speed of the traveling HST to be controlled, and sets the output rotation speed of the traveling HST as the target rotation speed. Control to be a number. Furthermore, a control apparatus controls the output of the corresponding turning motor according to each operation amount of a pair of right and left turning operation members.
Thus, by selecting the target rotation speed of the traveling HST from the plurality of target rotation speeds using a plurality of control functions, the brake turn control and the braking control are performed according to the input operation amount of the pair of left and right turning operation members. The transition between them can be performed smoothly. Further, when any one of the turning operation members is operated by the maximum amount, the brake turn can be surely performed.

Preferably, before Symbol controller, said when both of the pair of left and right swing operation member is operated to the maximum operating position, the normal control mode and the place of the brake turn control, the output rotational speed of the running HST The output is controlled to stop the pair of traveling units.

In this case, by operating both the left and right pair of pivot operation member to a maximum operating position, the control device instead of the output control for the swing motor, the output rotational speed of the running HST that stops the pair of running portions Control to output.
In this way, when both of the turning operation members are operated to the maximum, the drive current to the turning motor is increased by controlling to reduce the output rotation speed of the traveling HST instead of setting the turning motor to the maximum output. It is possible to perform effective braking control while preventing this.

  Preferably, the control device performs the normal control when only one of the pair of left and right turning operation members is operated when the output rotation speed of the traveling HST is equal to or less than the reference rotation speed. When the mode is executed and both of the pair of left and right turning operation members are operated to the maximum operation position, the output rotation speed of the traveling HST is set to the pair of traveling units instead of the normal control mode and the brake turn control. The output is controlled to stop.

In this case, even when the output rotational speed of the traveling HST is equal to or less than the reference rotational speed, if both the pair of left and right turning operation members are operated to the maximum operation position, the control device does not run the output control for the turning motor. The output rotation speed of the HST is controlled to an output that stops the pair of traveling units.
In this way, when both of the turning operation members are operated to the maximum, the drive current to the turning motor is increased by controlling to reduce the output rotation speed of the traveling HST instead of setting the turning motor to the maximum output. It is possible to perform effective braking control while preventing this.

  According to the working vehicle of the present invention, when the turning operation member is operated in a high-speed output state in which the traveling HST cannot stop the corresponding traveling unit even by the maximum output of the turning motor, By performing control to decelerate to the vehicle speed at which the corresponding traveling unit can be stopped by the maximum output of the motor, a brake turn (turning side traveling unit stop) is always possible if the maximum amount of the turning operation member is operated. Therefore, the turning radius can be reduced even when turning from a state where the vehicle speed is high.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
1 and 2 are a schematic side view and a schematic plan view of a walking snowplow 1 which is an example of a working vehicle according to the present invention. FIG. 3 is a schematic diagram of transmission in the walking snowplow 1 shown in FIGS. 1 and 2.

  As shown in FIGS. 1 and 2, the walking type snowplow 1 of the present embodiment includes a pair of left and right traveling units 40L and 40R and a working unit 20 that are driven using an output from an engine 31 that is a driving source. A traveling mechanism 120 including an HST (traveling HST) 102 that is inserted in a traveling system transmission path from the engine 31 to the traveling units 40L and 40R and can variably output in both forward and reverse directions; The turning mechanism 330 including the turning electric motors (turning motors) 33L and 33R, and the traveling rotational power from the traveling mechanism 120 and the braking rotational power from the turning mechanism 330 are input to the traveling units 40L and 40R. A pair of left and right differential mechanisms 103L, 103R that output rotational power toward each other, a travel operation member 53 for shifting the HST 102, and the pair of left and right turning Moving motor 33L, to manual operation of the 33R left and right rotation operation member 56L, and a 56R.

Specifically, the working unit 20 is here a snow removal unit, and is configured to remove snow on the running of the walking snowplow 1.
Specifically, the working unit 20 is supported by the machine frame 10 in the front-and-rear direction x1 of the machine frame 10 (see arrow x in FIG. 1), and a scraping auger 21 that scrapes snow. An auger housing 22 that covers the scraping auger 21, a blower housing 23 that is disposed in the longitudinal direction x rear x 2 of the auger housing 22, a blower 24 that is built in the blower housing 23, And a shooter 25 disposed above.

The scraping auger 21 collects snow on the traveling path of the walking type snowplow 1 toward the center of the machine body in the left-right direction (see arrow y in FIG. 2) and sends the snow toward the blower 24 in the blower housing 23. It is configured as follows.
Here, the scraping auger 21 is provided with a substantially cylindrical member having a spiral projection on the outer peripheral surface thereof, so that the axial direction is along the left-right direction y of the fuselage and close to the ground. It is arranged.
Both ends of the take-up auger 21 are pivotally supported by the auger housing 22 so as to be rotatable about its axis, and are driven to rotate by a driving force from the engine 31.

The auger housing 22 is a structure that pivotally supports the scraping auger 21, and has a function as a casing of the scraping auger 21.
The blower housing 23 is a housing in which the blower 24 is provided, and has a mechanism as a structure that supports the auger housing 22.

The blower 24 is configured to cause the snow transported into the blower housing 23 by the take-up auger 21 to jump toward the shooter 25 by being rotationally driven by a driving force from the engine 31. ing.
Here, the shooter 25 is a cylindrical member, and can be turned around a turning axis along a vertical direction with respect to a horizontal plane of the blower housing 23, and a tip portion thereof is along a horizontal direction. It can be rotated up and down around the rotation axis.

  By providing such a configuration, the working unit 20 is configured such that the snow transported into the blower housing 23 by the scraping auger 21 and jumped off by the blower 24 passes through the shooter 25 to the walking type snowplow 1. In addition to being removed from the road, the position of snow falling through the shooter 25 and falling on the ground can be adjusted.

The engine 31 is provided in a drive unit 30 disposed in the machine body front-rear direction x rear x2 of the working unit 20.
The HST 102 is provided in a transmission 100 disposed below the driving unit 30.

  The drive unit 30 transmits a driving force from the engine 31 to the working unit 20 via a work driving force transmission unit 12 such as a pulley and a belt, and travel driving force transmission unit 13 such as a pulley and a belt. The driving force can be transmitted to the transmission 100 via the transmission.

Specifically, the engine 31 has an output shaft 31a protruding from a front portion, and the output shaft 31a is supported by a bracket 11 provided in the body frame 10 through a bearing (not shown) in the middle. ing.
Here, the work drive force transmission means 12 is of a belt pulley type, and is provided on a drive pulley 131a to which power is transmitted from the output shaft 31a of the engine 31 and an input shaft 20a of the work unit 20. A driven pulley 133a and a belt 134a wound around the drive pulley 131a and the driven pulley 133a.

The transmission 100 is configured to transmit the driving force from the engine 31 to the traveling units 40L and 40R so that the walking snowplow 1 can be moved forward or backward.
The transmission 100 includes a transmission case 101 in addition to the HST 102, and an input shaft 104 projects forward from the transmission case 101. The input shaft 104 is pivotally supported by the bracket 11 at the front end.
Here, the traveling driving force transmission means 13 is of a belt pulley type, and a driving pulley 131b provided on the output shaft 31a of the engine 31 and a driven pulley provided on the input shaft 104 of the transmission 100. A pulley 133b, the pulley 131b, and a belt 134b wound around the pulley 133b are provided.

The drive unit 30 further includes a generator 260 (see FIG. 4 described later) that generates electric power by the rotational power of the engine 31.
In the present embodiment, the generator 260 also functions as a load detection sensor that detects the output rotational speed of the engine 31, as will be described later.
The driving unit 30 generates electric power by rotating the generator 260 by the engine 31, and the battery 32 is charged with the electric power generated by the generator 2600.
The drive unit 30 supplies power to the drive circuits of the left turn electric motor 33L and the right turn electric motor 33R of the turning mechanism 330 by the charged battery 32 (and the generator 260), respectively. The drive circuit is configured to drive the turning electric motors 33L and 33R while controlling the rotation speed of the turning electric motors 33L and 33R.
In such a configuration, the walking type snow remover 1 turns right or left by inputting the traveling rotational power from the traveling mechanism 120 and the braking rotational power from the turning mechanism 330 to the differential mechanisms 103L and 103R. It can be turned.

  In the present embodiment, as shown in FIG. 3, the HST 102 includes a pump shaft (the input shaft) 104, a pump body 105, a motor body 106, a motor shaft (output shaft) 107, and an output adjustment member 108. It has.

The pump shaft 104 is operatively connected to the engine 31, and the pump body 105 is supported by the pump shaft 104 so as not to be relatively rotatable.
The motor body 106 is fluidly connected to the pump body 105 via a pair of hydraulic oil lines 109, and the motor shaft 107 is configured to be rotated about the axis by the motor body 106. Yes.
And the said output adjustment member 108 is comprised so that the oil supply-and-discharge amount of at least one of the said pump main body 105 or the said motor main body 106 (here the said pump main body 105) can be changed.

In this embodiment, the pump main body 105 and the motor main body 106 are fixed to the rear end portion of the mission case 101 as shown in FIGS.
The pump body 105 is a variable displacement piston pump, and the output adjusting member 108 includes a movable swash plate.

When the plate surface of the movable swash plate is perpendicular to the axial direction of the pump shaft 104, the HST 102 can convey pressure oil to the motor body 106 even if the pump shaft 104 is driven to rotate. When the plate surface of the movable swash plate is tilted with respect to the axial direction of the pump shaft 104, pressure oil is applied to the motor body 106 in conjunction with the rotational drive of the pump shaft 104. The motor shaft 107 can be rotated by being conveyed.
The movable swash plate is configured such that the tilt angle of the pump shaft 104 with respect to the axial direction of the pump shaft 104 is adjusted, so that the motor is driven from the pump body 105 through the pair of hydraulic oil lines 109 while the pump shaft 104 rotates once. The amount of pressure oil conveyed to the main body 106, that is, the rotational speed of the motor shaft 107 can be adjusted.

  Here, the motor main body 106 is a constant capacity motor. However, the present invention is not limited to this, and both the pump main body 105 and the motor main body 106 may be variable capacity type, the pump main body 105 may be a constant capacity type, and the motor main body 106 may be A variable capacity type may be used.

The driven pulley 133b is externally fixed to the pump shaft 104, and a bevel gear 135 is externally fixed to the motor shaft 107.
The transmission 100 further includes first and second transmission shafts 136 and 115 and the pair of left and right differential mechanisms 103L and 103R.
A bevel gear 137 and a sprocket 139 are fitted and fixed to the first transmission shaft 136, and a sprocket 140 is fitted and fixed to the second transmission shaft 115. A braking mechanism may be interposed in a traveling system transmission path from the engine 31 to the traveling units 40L and 40R. For example, in the present embodiment, the first transmission shaft 136 is provided with a brake 138 that can brake the rotation of the first transmission shaft 136.

The bevel gear 137 in the first transmission shaft 136 and the bevel gear 135 in the motor shaft 107 are engaged with each other, and the sprocket 139 and the second transmission shaft 115 in the first transmission shaft 136 are engaged. A chain 141 is wound around the sprocket 140.
With this configuration, the transmission 100 transmits the driving force transmitted from the HST 102 to the first transmission shaft 136 via the bevel gear 135 and the bevel gear 137 to the sprocket 139, the chain 141, and the sprocket 140. Via the second transmission shaft 115.

  The differential mechanisms 103L and 103R are configured substantially symmetrically. Accordingly, since the left and right configurations are substantially the same, in the following description, the left differential mechanism 103L will be mainly described, and the right differential mechanism 103R is shown in parentheses.

The sun gear 110L (110R) in the differential mechanism 103L (103R) is fitted and fixed to the left half (right half) of the second transmission shaft 115, and meshes with a plurality of planetary gears 111L (111R). Yes. The carrier 112L (112R) is a substantially disk-shaped member that is fitted and fixed to one end of the travel drive shaft 113L (113R) and rotates integrally with the travel drive shaft 113L (113R).
A plurality of rotating shafts 114L (114R) project from the surface of the carrier 112L (112R) located on the opposite side of the travel drive shaft 113L (113R), and the plurality of rotating shafts 114L (114R) respectively A plurality of planetary gears 111L (111R) are rotatably supported.

The plurality of planet gears 111L (111R) mesh with the sun gear 110L (110R). The second transmission shaft 115 is pivotally supported on the carrier 112L (112R) via a bearing (not shown) at the left end (right end).
The ring gear 116L (116R) has a gear portion formed on the inner peripheral surface and the outer peripheral surface to form a substantially ring-shaped gear, and the gear portion on the inner peripheral surface side and the plurality of planetary gears 111L (111R) are mutually connected. It is designed to mesh.

The pair of left and right turning electric motors 33L and 33R are fixed to the outer surface of the mission case 101. Output shafts 117L and 117R of the electric motors 33L and 33R for turning are respectively inserted into the mission case 101.
A warm-up gear 118L is externally fixed to the output shaft 117L of the left-turn electric motor 33L, and the outer peripheral surface of the warm-up gear 118L and the ring gear 116L of the left differential mechanism 103L. The gear portion on the side meshes with each other.
Similarly, a warm-up gear 118R is fitted and fixed to the output shaft 117R of the right electric motor 33R, and the outer peripheral surface side of the warm-up gear 118R and the ring gear 116R of the right differential mechanism 103R. Are engaged with each other.

In the present embodiment, the traveling units 40L and 40R are a pair of left and right, and include the pair of left and right traveling drive shafts 113L and 113R, respectively.
Specifically, each of the traveling units 40L and 40R is a crawler type, and is disposed substantially symmetrically on both sides of the body frame 10 in the left-right direction (y direction) (FIG. 2). reference).
The traveling units 40L and 40R may be wheel type.
With this configuration, the resultant force of the traveling rotational power input from the HST 102 of the traveling mechanism 120 and the left braking rotational power input from the left turning electric motor 33L of the turning mechanism 330 is transmitted via the left differential mechanism 103L. It is transmitted to the left travel drive shaft 113L. Similarly, the resultant force of the traveling rotational power input from the HST 102 of the traveling mechanism 120 and the right braking rotational power input from the right turning electric motor 33R of the turning mechanism 330 is transmitted to the right via the right differential mechanism 103R. It is transmitted to the travel drive shaft 113R.

As shown in FIGS. 1 and 2, the pair of left and right traveling drive shafts 113L and 113R protrude outward in the left-right direction (y direction) of the transmission 100, and here, the traveling unit 40L, The track frames 41L and 41R in 40R are penetrated through the rear portions of the track frames 41L and 41R through bearings (not shown).
Drive sprockets 42L and 42R are fixed to the outer ends of the travel drive shafts 113L and 113R outside the track frames 41L and 41R.

Both ends of the driven shaft 45 disposed substantially parallel to the pair of left and right traveling drive shafts 113L and 113R are passed through the front frame portions of the track frames 41L and 41R via bearings (not shown). .
Drive sprockets 43L and 43R are fixed to both ends of the driven shaft 45 outside the track frames 41L and 41R. The drive sprockets 42L and 42R and the driven sprockets 43L and 43R are respectively The crawler belts 44L and 44R are wound around.

  In the present embodiment, the body frame 10 and the shaft that connects the left and right track frames 41L and 41R closer to the front are connected via an electric hydraulic cylinder 46, and at the rear of the body frame 10, A pair of left and right brackets 14L and 14R are rotatably supported by a pair of left and right travel drive shafts 113L and 113R via bearings (not shown).

In the present embodiment, the traveling operation member 53 and the turning operation members 56L and 56R are provided in the driving operation unit 50.
More specifically, the traveling operation member 53 is a manually operated traveling speed change lever for shifting the HST 102, and the turning operation members 56L and 56R are a pair of left and right turning electric motors 33L and 33R. It is a pair of left and right turning operation levers that can be operated manually to change the output of each.

In the walking snowplow 1 described above, the driving force from the engine 31 is transmitted to the working unit 20 via the work driving force transmission means 12 and also via the traveling driving force transmission means 13. It is transmitted to the transmission 100.
In the working unit 20, the driving auger 21 and the blower 24 are driven by the driving force from the engine 31.

  On the other hand, in the transmission 100, when the shift operation member 53 is shifted in the HST 102, the driving force transmitted to the transmission 100 is transmitted from the HST 102 to the motor shaft (output shaft) 107, the bevel gear 135, The bevel gear 137, the transmission shaft 136, the sprocket 139, the chain 141, the sprocket 140 and the transmission shaft 115 are transmitted to the sun gears 110L and 110R of the pair of left and right differential mechanisms 103L and 103R.

The driving force transmitted to the differential mechanism 103L is transmitted to the driving sprocket 42L of the traveling unit 40L via the sun gear 110L, the planetary gear 111L, the rotating shaft 114L, the carrier 112L, and the output shaft 113L.
The driving force transmitted to the differential mechanism 103R is transmitted to the driving sprocket 42R of the traveling unit 40R via the sun gear 110R, the planetary gear 111R, the rotating shaft 114R, the carrier 112R, and the output shaft 113R. The
In this way, the driving force from the engine 31 is transmitted to the pair of left and right traveling units 40L, 40R, and the traveling units 40L, 40R are rotationally driven.

Further, the walking type snow remover 1 includes a work clutch mechanism 132a inserted in a work system transmission path from the engine 31 to the working unit 20, and a work for performing a manual operation on the work clutch mechanism 132a. And a clutch operating member 54.
In the present embodiment, the work clutch mechanism 132a is disposed on the pulley 131a in the work driving force transmission means 12.
The work clutch mechanism 132a can be switched between a clutch engagement position where the clutch is engaged and a clutch disengagement position where the clutch is disengaged.
The working clutch mechanism 132a is in a power transmission state in which power is transmitted from the engine 31 to the working unit 20 by switching between the clutch engagement position and the clutch disengagement position (here, the pulley 131a is A state where the output shaft 31a is supported so as not to rotate relative to the output shaft 31a, that is, a clutch engaged state capable of transmitting power from the engine 31, and a power cutoff where power from the engine 31 to the working unit 20 is shut off. In this state, the pulley 131a is configured to be supported by the output shaft 31a so as to be relatively rotatable about the axis, that is, a clutch disengaged state in which power from the engine 31 is interrupted. .

  The work clutch operation member 54 is configured to selectively switch between a clutch engagement position and a clutch disengagement position of the work clutch mechanism 132a. Here, it is a working clutch switch provided in the driving operation unit 50 and capable of ON / OFF operation (see FIGS. 1 and 2).

By providing such a configuration, the walking type snowplow 1 can move from the engine 31 to the working unit 20 when the working clutch mechanism 132a is in a power transmission state based on an artificial operation of the working clutch operating member 54. When the driving force is transmitted and the work clutch mechanism 132a is in a power cut-off state, the drive force from the engine 31 to the working unit 20 is cut off.
The work clutch operation member 54 is provided with a vehicle speed control switch 54a that is turned on when the work clutch operation member 54 is in a power transmission state (ON state) and turned off when the power clutch is in a power cut-off state (OFF state). Thus, the state of the working clutch operating member 54 can be easily confirmed by visual inspection.

In the present embodiment, the driving operation unit 50 includes a handle unit 51 and an operation box 55 having a gripping unit for gripping the walking snowplow 1.
The handle portion 51 is formed in a substantially U shape in plan view (see FIG. 2), and a pair of support rods 51a and 51a are provided at both ends. The pair of support rods 51a, 51a extend forward and downward, respectively (see FIG. 1), and are connected to the pair of left and right brackets 14L, 14R.
The travel operation member 53 and the work clutch operation member 54 are provided in the operation box 55.
The traveling operation member 53 is at least a neutral position where the walking snowplow 1 is stopped, a forward maximum speed position where the vehicle speed of the walking snowplow 1 is maximum on the forward side, and slower than the forward maximum speed position. A predetermined forward-side maximum working speed position, a reverse-side maximum high-speed position at which the vehicle speed of the working vehicle speed 1 is maximum on the reverse side, and a predetermined reverse-side maximum working speed position that is slower than the reverse-side maximum speed position are configured. Yes. Specifically, the shift gate is formed in a staircase shape, the forward and reverse fastest positions are located at both ends of the shift gate, and the shift gate is advanced to the corner (that is, the operation direction changes). By configuring the traveling operation member 53 such that the maximum working speed position on the side and the reverse side is positioned, the traveling operation member 53 can be easily positioned at each operation position.
The pair of left and right turning operation members 56 </ b> L and 56 </ b> R is a pair of left and right turning operation levers that can be independently operated, and the left and right of the handle portion 51 are supported by the front end portion pivotally supported by the handle portion 51. It is provided below both sides and is urged in a direction (downward) away from the handle portion 51 by an urging member (not shown).
A battery stand 57 is installed between the pair of support rods 51a and 51a.

  The walking snowplow 1 has a traveling clutch mechanism 140 (see FIG. 4 to be described later) inserted in a traveling system transmission path from the engine 31 to the traveling units 40L and 40R, and a traveling clutch mechanism. And a travel clutch operating member 52 for performing a manual operation. The travel clutch operating member 52 is provided above the handle portion 51 with the front end portion pivotally supported by the handle portion 51, and is separated from the handle portion 51 by a biasing member (not shown). It is biased in the direction (upward).

Here, the control aspect of the walking type snowplow 1 in this embodiment is demonstrated.
FIG. 4 is a system block diagram showing a schematic configuration of the control mechanism 200 of the walking snowplow 1 in the present embodiment.

As shown in FIG. 4, the control mechanism 200 of the walking snowplow 1 in this embodiment includes a travel actuator 210 that operates the output adjustment member 108 of the HST 102, and an operation position of the output preparation member 108 (of the movable swash plate). Angle)), an HST output sensor 220 for detecting the output rotation speed of the HST 102, a travel operation position detection sensor 230 for detecting the operation position of the travel operation member 53, and the turning electric motor. Rotation output sensors 240L and 240R for detecting output rotation speeds of 33L and 33R, turning operation position detection sensors 250L and 250R for detecting operation positions of the turning operation members 56L and 56R, respectively, and output rotation of the engine 31 A load detection sensor that detects the load in the working unit 20 by detecting the number ( A serial generator) 260, and a said constituent signal transmittable electrically connected control device 270.
The load detection sensor 260 may be a hydraulic pressure detection sensor that detects the hydraulic pressure of the hydraulic oil that operates the working unit 20 instead of the generator.

In the present embodiment, the traveling operation position sensor 230 and the turning operation position detection sensors 240L and 240R are configured by, for example, potentiometers that detect the operation lever angles in the traveling operation member 53 and the turning operation members 56L and 56R, respectively. . The operation position sensor 280 is configured by, for example, a potentiometer that detects the movable swash plate angle of the output adjustment member 108.
The HST output sensor 220 is an HST output rotational speed sensor that detects the rotational state of the motor shaft (output shaft) 107 in the HST 102, the HST rotational speed sensor that detects the rotational speed of the motor shaft 107, and the An HST rotation direction sensor that detects the rotation direction of the motor shaft 107 is included.
The HST output sensor 220 includes a first HST output sensor 221 and a second HST output sensor 222. That is, two HST output sensors 221 and 22 are provided for one HST 102, and safety is enhanced by double detection of the output rotation speed of the HST 102.

The control device 270 is configured to control the output of the HST 208 in accordance with the operation amount of the travel operation member 53 in a normal control mode described later.
That is, the traveling actuator 210 is configured to output the output adjusting member 108 in the HST 102 based on a control signal transmitted from the control device 270 according to the operation amount of the traveling operation member 53 detected by the operating position sensor 280. Is adjusted (movable swash plate angle adjustment).
Further, in the normal control mode, the control device 270 controls the output of the electric motors 33L and 33R for turning via a predetermined motor drive driver (not shown) according to the operation amount of the turning operation members 56L and 56R. Is configured to do.
In the present embodiment, the operation box 55 is provided with a pair of pilot lamps 58L and 58R for notifying an operator when the turning electric motors 33L and 33R are in a malfunction state such as an operation failure. It has been.

The control device 270 is also electrically connected to the work clutch operation member 54, the work clutch mechanism 132a, the travel clutch mechanism 140, and the travel clutch operation member 52.
The travel clutch operation member 52 is configured to transmit a switching signal for switching between a vehicle travel state in which the walking snowplow 1 is traveled and a vehicle stop state in which the walk snowplow 1 is stopped to the control device 270. Yes.
The travel clutch operating member 52 is a deadman clutch lever that is biased toward the vehicle stop state. The travel clutch operation member 52 is provided in the driving operation unit 50 as shown in FIGS. 1 and 2.

When the travel clutch operation member 52 is released from the vehicle travel state, the walking snowplow 1 moves the work clutch mechanism 132a to the power shut-off state when the travel clutch operation member 52 is automatically moved to the vehicle stop state. It is configured as follows.
Further, the walking type snowplow 1 is configured such that when the travel clutch operating member 54 is manually operated to the clutch engagement position after the travel clutch operating member 52 is manually operated in the vehicle running state, the work clutch The operation member 54 is configured to maintain the clutch engagement position until the travel clutch operation member 52 is manually operated while the vehicle is stopped.
Further, in the walking snowplow 1, even when the travel clutch operating member 52 is manually operated in a vehicle stop state, the work clutch operating member 54 is continuously operated to the clutch engagement position. The clutch engagement position is maintained.

In the present embodiment, the control device 270 includes a calculation unit 271 and a storage unit 272. The calculation unit 271 includes a CPU and executes various calculation processes. The storage unit 272 includes a ROM 272a in which a control program such as a control mode is stored, a RAM 272b in which information is temporarily stored, a storage area (for example, EEPROM 272c) that is not lost even when the power for storing and saving setting values is turned off, and the like. Yes.
In the present embodiment, the control device 270 has a plurality of control modes (stored in the storage unit 271), and the traveling actuator is based on a received signal from each sensor according to the control mode. 210, a control signal is transmitted to the electric motors 33L and 33R for turning, the traveling clutch mechanism 140, the working clutch mechanism 132a, and the like.

In the present embodiment, the control device 270 has a load control mode, a brake turn control mode, and a braking control mode in addition to the normal control mode as control modes executed during traveling.
When the traveling load detected by the load detection sensor 260 is equal to or greater than a predetermined value (that is, when the output speed of the engine 31 is equal to or smaller than the predetermined value), the control device 270 loads the load from the normal control mode. The control shifts to the control mode, and the output rotational speed of the HST 102 is decelerated and controlled so that the traveling load is reduced by reducing the vehicle speed. Here, the control device 270 uses, as the target rotation output of the HST 102, an output obtained by multiplying a reference output corresponding to the operation amount of the travel operation member 53 by a deceleration rate based on the detection result of the load detection sensor 260. The operation of the output adjusting member 108 is controlled.
In this embodiment, the operation box 55 is provided with a vehicle speed control switch 59 for switching whether or not to automatically shift to the load control. That is, when the vehicle speed control switch 59 is turned on, the transition to the load control mode is permitted, and when the vehicle load is over the predetermined value, the transition to the load control mode is permitted. do not do.
The vehicle speed control switch 59 is provided with a vehicle speed control switch 59a that is turned on when the vehicle speed control switch 59 is in an ON state and is turned off when the vehicle speed control switch 59 is in an OFF state. It can be confirmed.

  When the HST 102 is in a high-speed output state in which the corresponding traveling units 40L and 40R cannot be stopped even by the maximum output of the electric motors 33L and 33R for turning, the turning operation members 56L and 56R. Is operated, the normal control mode is shifted to the brake turn control mode, and when the turning operation members 56L and 56R are operated from the non-operation position to the maximum operation position, the output rotation speed of the HST 102 is set for the turning. Deceleration control is performed such that the maximum output of the electric motors 33L, 33R becomes a reference rotation speed that can reduce the rotation speed of the corresponding traveling unit 40L, 40R to 0 or less, and according to the operation amount of the turning operation members 56L, 56R. Output control of the electric motors 33L and 33R for turning is performed.

  In addition, when both the turning operation members 56L and 56R are operated to the maximum operation position, the control device 270 shifts from the normal control mode or the brake turn control to the braking control mode, and the output rotation speed of the HST 102 Is controlled so as to stop both the traveling units 40L and 40R.

The brake turn control mode and the brake control mode will be described in more detail.
5 and 6 show graphs of the turning control function f1 and the braking control function f2 used in the brake turn control mode and the braking control mode of the walking type snowplow of the present embodiment. 5 and 6 are graphs showing the target vehicle speed with respect to the operation amount of the turning operation members 56L and 56R. 5 and 6, the operation amounts of the turning operation members 56L and 56R are expressed as a ratio when the maximum operation amount of the turning operation members (turning operation levers) 56L and 56R is 100%.

In the present embodiment, as shown in FIG. 5, the state in which the output rotational speed of the HST 102 exceeds the forward maximum working speed Sm (<forward maximum high speed SM) is the maximum of the electric motors 33L and 33R for turning. It is defined as a high-speed output state in which the corresponding traveling units 40L and 40R cannot be brought into a stopped state by the output.
That is, when the turning operation members 56L and 56R are operated in a state where the output rotation speed of the HST 102 exceeds the forward maximum working speed Sm, the control device 270 shifts to the brake turn control mode.
In the present embodiment, the case where the brake turn control is executed at the time of forward movement is exemplified, but the brake turn control can be similarly performed at the time of backward movement.

First, a control mode when only one of the pair of left and right turning operation members 56L and 56R is operated in the high-speed output state will be described.
For example, when the left turning operation member 56L is operated in the high-speed output state, the control device 270 shifts to the brake turn control mode, and the left turning operation member 56L is operated from the non-operation position to the maximum operation position. The output rotation speed of the HST 102 is set to a reference rotation speed (that is, the forward maximum working speed Sm) that can reduce the rotation speed of the corresponding traveling unit 40L to 0 or less by the maximum output of the left-turn electric motor 33L. Decelerate control.

  Specifically, the control device 270 first outputs the output rotation speed S1 of the HST 102 immediately before the operation of the left turning operation member 56L (in the non-operation position) and the output of the HST 102 at the maximum operation position of the left turning operation member 56L. A turning control function f1 (FIG. 5) is calculated by linear interpolation between the rotational speed (that is, the forward maximum working speed Sm). The left turn operation position detection sensor 250L detects the operation amount UL (%) of the left turn operation member 56L.

Then, as shown in FIG. 5, the control device 270 calculates a target output rotation speed S2 of the HST 102 corresponding to the operation amount of the left turning operation member 56L based on the turning control function f1. Specifically, the target output rotational speed S2 is obtained by the following mathematical formula.
That is,
S2-Sm = (S1-Sm) (1-UL / 100)
Further, the control device 270 controls the operation of the output adjustment member 108 via the travel actuator 210 so that the output rotation speed of the HST 102 becomes the target output rotation speed S2.
In the present embodiment, the control device 270 calculates the deceleration rate c = S2 / S1, and controls the travel actuator 210 to a position where the output adjusting member 108 becomes the deceleration rate c.

Then, the control device 270 controls the operation of the left turning electric motor 33L according to the operation amount of the left turning operation member 56L so that the output corresponds to the operation amount UL of the left turning operation member 56L. At this time, when the operation amount UL is the operation amount to the maximum operation position (100%), the output rotation speed of the HST 102 is controlled to be reduced to the forward maximum working speed Sm, and the left-turn electric motor 33L Is controlled to the maximum output, and a brake turn (turning using the driving force of the right traveling unit 40R on the opposite side to the turning side with the left traveling unit 40L on the turning side stopped) is realized. The
The same control is performed when only the right turning operation member 56R is operated.

  As described above, when the HST 102 is in a high-speed output state in which the corresponding traveling units 40L and 40R cannot be stopped even by the maximum output of the electric motors 33L and 33R for turning, one of the turning operation members 56L and 56R is When operated, the turning operation members 56L and 56R are controlled by decelerating to the vehicle speed at which the corresponding traveling units 40L and 40R can be stopped by the maximum output of the turning electric motors 33L and 33R. When the maximum amount is operated, a brake turn (turning side traveling unit stop) is always possible, so that the turning radius can be reduced even when turning from a state where the vehicle speed is high.

Next, a control mode when both the left and right turning operation members 56L and 56R are operated in the high-speed output state will be described.
In this embodiment, when both the pair of left and right turning operation members 56L and 56R are operated, first, the control device 270 reduces the output rotation speed of the HST 102 with respect to the operation amount of the turning operation members 56L and 56R. The linear rotation control function f1 with respect to the output rotation speed of the HST 102, and the rotation speed of the traveling units 40L and 40R corresponding to the maximum output of the electric motors 33L and 33R for rotation can be set to 0 or less. The turning control function f1 (FIG. 5) for decelerating to Sm, and the linear braking control function f2 relating to the output rotation speed reduction amount of the HST 102 with respect to the operation amount of the turning operation members 56L and 56R, When the turning operation members 56L and 56R of the HST 102 are both operated to the maximum, the output rotational speed of the HST 102 is set to the pair of travels. 40L, and calculates a braking control function such that the output to stop the 40R f2 (Fig. 6). Based on the turning control function f1, the first and second target rotational speeds S2L and S2R of the HST 102 at the operation amounts UL and UR of the pair of left and right turning operation members 56L and 56R are calculated, and the braking is performed. Based on the control function f2, the third target rotational speed T2 of the HST 102 at the smaller operation amount V of the operation amounts of the pair of left and right turning operation members 56L, 56R is calculated, and the first, second and third The output rotation speed of the HST 102 is controlled so that the target rotation speed is the smallest rotation speed among the target rotation speeds S2L, S2R, and T2, and the left and right turning operation members 56L and 56R are respectively set. The output control of the pair of left and right electric motors 33L or 33R is performed according to the operation amount.

This will be described more specifically.
FIG. 7 is a diagram comparing FIG. 5 and FIG. 6 in order to explain the control mode when both the turning operation members are operated in the present embodiment.
First, the control device 270 calculates the turning control function f1, the output rotation speed T1 (= S1) of the HST 102 immediately before the turning operation members 56L and 56R (in the non-operation position), and the turning operation member. A braking control function f2 is calculated by linearly interpolating between the output rotation speed of the HST 102 at the maximum operation position of 56L and 56R and the output (here, the output rotation speed of 0) that stops the traveling units 40L and 40R. The left turn operation position detection sensor 250L detects the operation amount UL (%) of the left turn operation member 56L, and the right turn operation position detection sensor 250R detects the operation amount UR ( %) Is detected.

Subsequently, as shown in FIG. 7, the control device 270 determines the first and second target rotational speeds S2L and S2R of the HST 102 at the operation amounts of the left and right turning operation members 56L and 56R from the calculated turning control function f1. And the third target rotational speed T2 of the HST 102 at the smaller operation amount V of the operation amounts of the pair of left and right turning operation members 56L and 56R is calculated from the calculated braking control function f2. In the present embodiment, the deceleration rate is calculated instead of the first, second, and second target rotational speeds.
7 shows an example in which the operation amount UL of the left turning operation member 56L is smaller than the operation amount UR of the right turning operation member 56R. That is, the smaller operation amount V among the operation amounts of the pair of left and right turning operation members 56L and 56R is equal to the operation amount UL of the left turning operation member 56L.

Thereafter, the control device 270 controls the target rotation of the HST 102 that should control the smallest rotation speed (that is, the rotation speed at which the vehicle speed is the lowest) among the first, second, and third target rotation speeds S2L, S2R, and T2. The output adjusting member 108 is controlled to operate via the travel actuator 210 so that the output rotational speed of the HST 102 becomes the target rotational speed.
In the example of FIG. 7, the second target rotational speed S2R is adopted as the target rotational speed.

In addition, the control device 270 controls the outputs of the corresponding electric motors 33L, 33R corresponding to the operation amounts of the pair of left and right turning operation members 56L, 56R.
At this time, when both the operation amounts are the operation amounts to the maximum operation position (100%), the control device 270 outputs the output rotation speed of the HST 102 instead of the output control for the electric motors 33L and 33R for turning. Is controlled to an output (output rotational speed 0) that stops the pair of travel portions 40L, 40R. That is, in this case, the turning electric motors 33L and 33R do not operate.

Thus, when both of the turning operation members 56L and 56R are operated to the maximum, by controlling the turning electric motors 33L and 33R to reduce the output rotation speed of the HST 102 instead of setting the maximum output, Effective braking control can be performed while preventing an increase in drive current to the electric motors 33L and 33R for turning.
Further, by selecting the target rotation speed of the HST 102 from the plurality of target rotation speeds S2L, S2R, T2 using the plurality of control functions f1, f2, the input operation amount of the pair of left and right turning operation members 56L, 56R is obtained. Accordingly, the transition between the brake turn control and the brake control can be smoothly performed.
Further, when any one of the turning operation members 56L and 56R is operated by the maximum amount, the brake turn can be surely performed.

In the present embodiment, the control device 270 uses the HST output sensor 220 to detect whether or not the output rotation speed of the HST 102 has reached the target output rotation speed in the brake turn control mode and the braking control mode. .
If the HST output sensor 220 cannot be detected due to some failure, the output rotation speed of the HST 102 is estimated based on the detection value from the operating position sensor 280 that detects the operating position of the output adjusting member 108. To do.
Thereby, even if the HST output sensor 220 fails, it is possible to prevent the execution of the brake turn control mode and the brake control mode from being hindered.

When the output amount of the HST 102 is decelerated and controlled to turn or stop (decelerate) in the brake turn control mode and the brake control mode, and then the operation amount of the turning operation members 56L and 56R returns to 0 again. First, the control device 270 performs speed increasing control for increasing the output rotation speed of the HST 102 using a predetermined recovery control function (not shown).
Thereby, sudden acceleration at the end of the turning operation can be prevented.

In addition, when the condition for shifting to the brake turn control mode or the braking control mode is satisfied during execution of the load control mode (the condition for shifting to the load control mode is satisfied during execution of the brake turn control mode or braking control mode) In the same manner, the target output rotation speed of the HST 102 in both control modes is calculated and compared, and the smaller target output rotation speed is adopted.
As a result, it is possible to prevent inconvenience that a brake turn cannot be performed or load control cannot be performed when conditions for shifting to a plurality of control modes are satisfied at the same time.

  In the present embodiment, when the output rotational speed of the HST 102 is equal to or lower than the reference rotational speed (the maximum forward working speed Sm in FIG. 5), the control device 270 includes the pair of left and right turning operation members 56L, When any one of 56R is operated, the normal control mode is executed, and when both the pair of left and right turning operation members 56L and 56R are operated, unless both are operated to the maximum operation position, When the output rotation speed of the HST 102 is controlled to decelerate the pair of traveling portions 40L and 40R, and both the pair of left and right turning operation members 56L and 56R are operated to the maximum operation position, the normal control mode and the Instead of the brake turn control, the output rotational speed of the HST 102 is controlled to an output that stops the pair of traveling units 40L and 40R.

In this case, even when the output rotation speed of the HST 102 is equal to or less than the reference rotation speed Sm, when both the pair of left and right turning operation members 56L and 56R are operated, the control device 270 causes the braking control function f2 (FIG. 6) is used to control the deceleration of the HST102.
At this time, when both the operation amounts are the operation amounts to the maximum operation position (100%), the control device 270 outputs the output rotation speed of the HST 102 instead of the output control for the electric motors 33L and 33R for turning. Is controlled to an output (output rotational speed 0) that stops the pair of travel portions 40L, 40R.

  Thus, even when the reference base point number Sm or less, when both of the turning operation members 56L and 56R are operated to the maximum, the output rotation speed of the HST 102 is set instead of setting the turning electric motors 33L and 33R to the maximum output. By controlling to decrease, effective braking control can be performed while preventing an increase in drive current to the electric motors 33L and 33R for turning.

The embodiment according to the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and various improvements, changes, and modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the configuration in which the left and right turning electric motors 33L and 33R are provided as the turning motor has been described as an example, but the present invention is not limited to such a configuration.
That is, it is possible to provide a single turning motor and transmit the turning rotational power from the single turning motor to the pair of left and right differential mechanisms 103L and 103R so that the rotation directions are reversed.
Alternatively, a clutch mechanism is provided in the transmission path from the single swing motor to the pair of left and right differential mechanisms 103L and 103R, and one of the differential mechanisms 103L and 103R according to the operation of the swing operation members 56L and 56R. It is also possible to configure so that the turning rotational power is input only to the other and no turning rotational power is input to the other differential mechanism 103R, 103L (one differential mechanism 103R, 103L is fixed).

  Moreover, in the said embodiment, although the structure provided with the left-right paired turning operation levers 56L and 56R as a turning operation member was illustrated, it is good also as providing a single turning operation member, such as a handle.

  Furthermore, in the above-described embodiment, the example in which the driving output of the working unit 20 is obtained from the HST 102 that drives the traveling units 40L and 40R has been described. However, the working unit HST is provided separately from the HST 102, and the HST 102 is traveling. It is good also as functioning as driving | running | working HST provided only for the drive of the parts 40L and 40R.

FIG. 1 is a schematic side view of a walking snowplow that is an example of a working vehicle according to the present invention. FIG. 2 is a schematic plan view of a walking snowplow that is an example of a working vehicle according to the present invention. FIG. 3 is a schematic diagram of transmission in the walking type snowplow shown in FIGS. 1 and 2. FIG. 4 is a system block diagram showing a schematic configuration of the control mechanism of the walking snowplow in the present embodiment. FIG. 5 is a graph of a turning control function used in the brake turn control mode and the braking control mode of the walking snowplow of the present embodiment. FIG. 6 is a graph of a braking control function used in the brake turn control mode and the braking control mode of the walking snowplow of the present embodiment. FIG. 7 is a diagram comparing FIG. 5 and FIG. 6 in order to explain the control mode when both of the turning operation members are operated in the present embodiment.

1 Walking snowplow (work vehicle)
33L, 33R Electric motor for turning (turning motor)
40L, 40R Traveling part 53 Traveling operation members 56L, 56R Turning operation member 102 HST (traveling HST)
103L, 103R Differential mechanism 120 Travel mechanism 200 Control mechanism 270 Controller 330L, 330R Turning mechanism f1 Turning control function f2 Braking control function Sm Reference rotation speed S2L First target rotation speed S2R Second target rotation speed T2 Third target rotation speed

Claims (2)

The pair of left and right differential mechanisms synthesize the traveling rotational power input from the traveling mechanism including the traveling HST and the braking rotational power input from the turning mechanism including the pair of left and right turning motors toward the pair of left and right traveling units, respectively. The control device of the control mechanism is configured to output and controls output of the travel HST and the pair of left and right turning motors in the normal control mode according to the operation amounts of the traveling operation member and the pair of left and right turning operation members. A working vehicle configured to perform,
When the turning operation member is operated in a high-speed output state where the traveling HST cannot stop the corresponding traveling unit even by the maximum output of the turning motor, the control device enters the normal control mode. Instead, it is configured to perform brake turn control,
When one of the pair of left and right turning operation members is operated , the brake turn control is performed when the output rotation speed of the traveling HST immediately before the turning operation member is operated and the turning operation member is operated to the maximum operation position. The target of the travel HST with respect to the operation amount of the swing operation member based on the reference rotational speed of the travel HST set so that the rotation speed of the corresponding travel unit is 0 or less by the maximum output of the swing motor A turning control function related to the output rotation speed is calculated, and the traveling HST is subjected to deceleration control so that the traveling HST becomes a target output rotation speed calculated based on an operation amount of the turning control function and the turning operation member. the have the row output control of the swing motor in accordance with the amount of operation of the swing operation member, and wherein when both of the pair of left and right swing operation member is operated, the In addition to the turning control function, the amount of operation of the turning operation member based on the output rotation number of the traveling HST immediately before the operation of the turning operation member and the output rotation number of the traveling HST that stops the pair of traveling units. A braking control function relating to a target output rotational speed of the travel HST is calculated, and first and second target rotations of the travel HST corresponding to respective operation amounts of the pair of left and right turning operation members based on the turning control function. And a third target rotational speed of the travel HST corresponding to the smaller operation amount of the operation amounts of the pair of left and right turning operation members based on the braking control function, and calculating the first, The output rotation speed of the travel HST is controlled so that the lowest rotation speed of the second and third target rotation speeds is set as the target rotation speed, and the left and right It controls output of the swing motor in accordance with respective operation amount of the rotation operation member pairs,
When both of the pair of left and right turning operation members are operated to the maximum operation position, the control device changes the output rotation speed of the traveling HST to the pair of traveling units instead of the normal control mode and the brake turn control. A working vehicle characterized in that the output is controlled to stop . The control device executes the normal control mode when only one of the pair of left and right turning operation members is operated when the output rotation speed of the traveling HST is equal to or less than the reference rotation speed, When both the pair of left and right turning operation members are operated to the maximum operation position, instead of the normal control mode and the brake turn control, the output rotation speed of the traveling HST is stopped at the pair of traveling units. The working vehicle according to claim 1 , wherein the working vehicle is controlled to output.

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