JP2016003706A - Work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a configuration capable of adjusting a deceleration in response to an operator's intention in a work vehicle including a hydraulic continuously variable transmission.SOLUTION: A tractor (work vehicle) comprises: an engine; a hydraulic continuously variable transmission; a travel unit; a depression amount detector; and a control unit. The hydraulic continuously variable transmission changes gears to transmit an output of the engine. The travel unit travels a vehicle body by an output from the continuously variable transmission. The depression amount detector detects a depression amount of a brake pedal. The control unit reduces a vehicle velocity by controlling an HMT at a deceleration calculated to become higher as the depression amount is larger on the basis of the depression amount detected by the depression amount detector.

Description

  The present invention relates to a work vehicle that travels by changing the output of an engine with a continuously variable transmission.

  2. Description of the Related Art Conventionally, in a work vehicle such as a tractor, a configuration including a hydraulic continuously variable transmission is known in order to smoothly run in a farm field. Patent Document 1 discloses this type of continuously variable transmission, and Patent Document 2 discloses a work vehicle equipped with a continuously variable transmission.

  The continuously variable transmission of Patent Document 1 is an HMT (hydraulic-mechanical transmission) including an HST (hydrostatic continuously variable transmission) and a planetary gear type differential. This continuously variable transmission has a mode in which the engine output is shifted by the HST and a mode in which the engine output is shifted by the HST and the planetary gear.

  In addition, when the work vehicle of Patent Document 1 detects that the brake pedal has been depressed more than a predetermined amount (when the sensor is turned on), a work curve (speed ratio control) determined based on the HST speed ratio at that time. The gear ratio is changed according to the curve. Further, in Patent Document 1, a potentiometer is attached to a brake pedal, the momentum that the brake pedal is stepped on is detected based on the detected value of the potentiometer, and one of a plurality of gear ratio control curves is selected based on this momentum. The control is also disclosed.

  The work vehicle of patent document 2 detects the depression amount (operation position) of a brake pedal. In this work vehicle, when the amount of depression of the brake pedal increases, the continuously variable transmission first changes to the low speed side, and then the braking force of the brake acts.

Japanese Patent No. 4439183 Japanese Patent No. 50275596

  However, in the configuration of Patent Document 1, how the work vehicle is decelerated is determined based on the HST gear ratio or the momentum at which the brake pedal is depressed at the time when the brake pedal switch is turned on. Therefore, it is difficult for the operator to operate the brake and stop it at a desired position. In Patent Document 2, although the braking force increases in accordance with the depression amount of the brake pedal, the reduction amount of the vehicle speed per unit time cannot be adjusted.

  The present invention has been made in view of the above circumstances, and its main object is to provide a configuration capable of adjusting the deceleration according to the operator's intention in a work vehicle including a hydraulic continuously variable transmission. is there.

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to an aspect of the present invention, a work vehicle having the following configuration is provided. That is, this work vehicle includes an engine, a continuously variable transmission, a traveling unit, a stepping amount detection unit, and a control unit. The continuously variable transmission is hydraulic and shifts the output of the engine. The travel unit travels the vehicle body by the output of the continuously variable transmission. The depression amount detection unit detects a depression amount of a brake pedal or a clutch pedal. When the amount of decrease in vehicle speed per unit time is referred to as deceleration, the control unit increases the value as the stepping amount increases based on the stepping amount detected by the stepping amount detection unit. The continuously variable transmission is controlled with the calculated deceleration to reduce the vehicle speed.

  Thereby, the operator can adjust the deceleration based on the depression amount of the brake pedal or the clutch pedal, so that the work vehicle can be stopped at a desired position.

  In the work vehicle, it is preferable that the control unit decelerates the vehicle speed in a state where power transmitted from the engine to the continuously variable transmission is connected when the stepping amount becomes equal to or greater than a predetermined threshold.

  Thereby, for example, the work vehicle can be stopped while maintaining the power transmitted from the engine to the continuously variable transmission.

  The work vehicle preferably has the following configuration. That is, the work vehicle includes a brake that brakes the traveling unit. The control unit cuts off the power transmitted from the engine to the traveling unit and operates the brake when the stepping amount becomes a predetermined threshold value or more.

  Thereby, since the deceleration by the continuously variable transmission has a limit, the work vehicle can be stopped suddenly by using the brake as described above.

  The work vehicle preferably has the following configuration. That is, in addition to the depression amount detection unit, an auxiliary depression amount detection unit that detects the depression amount of the brake pedal or the clutch pedal by a method different from the depression amount detection unit is provided. The control unit decelerates the vehicle speed at the deceleration larger than the calculated deceleration when the detection result of the depression amount detection unit and the detection result of the auxiliary depression amount detection unit do not match.

  Thereby, the malfunction of the depression amount detection part can be detected. Furthermore, when there is a malfunction in the stepping amount detection unit, it can be operated to the safe side.

The side view of the tractor concerning a 1st embodiment of the present invention. The skeleton figure which shows the power transmission path | route of a tractor. The top view which shows the operation tool provided in the cabin. The block diagram which shows the structure which controls HMT. The flowchart which shows the deceleration adjustment control which a transmission control part performs. The graph which shows the relationship between the depression amount of a brake pedal, and deceleration. The graph which shows the change of the vehicle speed according to the depression amount of a brake pedal. The skeleton figure which shows the power transmission path | route of the tractor which concerns on 2nd Embodiment.

  Next, an embodiment of the invention will be described with reference to the drawings. FIG. 1 is a side view of a tractor 10 as a work vehicle according to a first embodiment of the present invention.

  The tractor 10 is a work vehicle for agricultural work, and can be equipped with various work machines (attachments) such as a rotary, a loader, a plow, a box scraper, and the like to perform various work using the work machine. it can. In the following description, “left side”, “right side”, and the like simply mean the left side and the right side in the direction in which the tractor 10 moves forward.

  As shown in FIG. 1, the tractor 10 includes a vehicle body 11, a pair of left and right front wheels (running unit) 12, and a pair of left and right rear wheels (running unit) 13. A bonnet 14 is disposed at the front of the vehicle body 11, and an engine 15 is disposed inside the bonnet 14.

  A mission case 16 is disposed between the pair of left and right rear wheels 13. The output of the engine 15 is shifted by a hydraulic-mechanical transmission (hereinafter referred to as “HMT”) 17 in the transmission case 16 and transmitted to the rear wheel 13. Details of the HMT 17 will be described later.

  A lower link 18, a top link 19, and a PTO shaft 20 are disposed at the rear of the mission case 16. A work machine lifting mechanism 21 is attached to the top of the mission case 16. The work machine is connected to the lower link 18 and the top link 19 and is driven by the PTO shaft 20. Moreover, the working machine lifting mechanism 21 can lift and lower the connected working machines.

  A cabin 22 for an operator (driver) to board is disposed above the mission case 16 and behind the hood 14. A driver seat 70 is provided inside the cabin 22, and a number of operating tools for operation by an operator are provided in the vicinity of the driver seat 70. The operator operates the operation tool to run the tractor 10 and operate various attachments. Details of this operation tool will be described later.

  Next, the configuration of the drive transmission path of this embodiment, particularly the HMT (continuously variable transmission) 17, will be described with reference to FIG. FIG. 2 is a skeleton diagram showing the power transmission path of the tractor 10. The HMT 17 includes an HST (hydrostatic continuously variable transmission) 30 and a planetary gear mechanism 40.

  The HST 30 includes a hydraulic pump 31 and a hydraulic motor 32. The hydraulic pump 31 discharges hydraulic oil when the output of the engine 15 is transmitted through the engine output shaft 15a. The hydraulic pump 31 includes a movable swash plate 31a, and the flow rate of discharged hydraulic oil changes according to the inclination angle of the movable swash plate 31a. The hydraulic motor 32 is driven by hydraulic oil discharged from the hydraulic pump 31. The output of the hydraulic motor 32 is transmitted to the planetary gear mechanism 40 via the motor output shaft 32a.

  With this configuration, the output of the engine 15 can be shifted and transmitted to the planetary gear mechanism 40 by controlling the inclination angle of the movable swash plate 31a.

  The planetary gear mechanism 40 includes a sun gear 41, an internal gear 42, a carrier 43, a planetary gear 44, and a plurality of gears and a transmission shaft.

  The output of the engine 15 is transmitted to the gear 45 via the engine output shaft 15a. The power transmitted to the gear 45 is transmitted to the planetary gear 44 via the gear 46 and the sun gear 41. On the other hand, the output of the HST 30 is transmitted to the planetary gear 44 via the motor output shaft 32a, the gear 47, and the internal gear 42 having teeth formed on the inner and outer circumferences.

  In this way, power is transmitted to the planetary gear 44 from two paths. The planetary gear 44 rotates around the planetary axis and revolves around the HMT output shaft 48. The power generated by the rotation of the planetary gear 44 is transmitted to the gear 49. The power generated by the revolution of the planetary gear 44 is transmitted to the carrier 43. The power transmitted to the gear 49 is used as power on the high speed side, and the power transmitted to the carrier 43 is used as power on the low speed side.

  The planetary gear mechanism 40 includes a high speed side clutch 51 and a low speed side clutch 52. The high-speed side clutch 51 can be switched between transmitting power from the gear 49 to the HMT output shaft 48 or shutting it off. The low speed side clutch 52 can be switched between transmitting power from the carrier 43 to the HMT output shaft 48 or shutting it off. Note that the output of the engine 15 is not transmitted to the rear wheel 13 side because both the high speed side clutch 51 and the low speed side clutch 52 cut off the power.

  Further, the power transmitted to the carrier 43 is transmitted to the reverse gear 55 via the gear 53 and the gear 54. When the reverse gear 55 and the HMT output shaft 48 are connected by the reverse clutch 56 in a state where both the high speed side clutch 51 and the low speed side clutch 52 are shut off, the power of the reverse gear 55 is transferred to the HMT output shaft 48. Communicated. Thereby, the HMT output shaft 48 can be rotated in the reverse direction.

  As described above, the output of the engine 15 and the output of the HST 30 are combined in the planetary gear mechanism 40, and the combined output is transmitted to the HMT output shaft 48.

  Further, an auxiliary transmission 60 and a differential mechanism 65 are arranged downstream of the planetary gear mechanism 40 in the power transmission direction. The auxiliary transmission 60 changes the power transmitted from the planetary gear mechanism 40. The auxiliary transmission 60 includes two gears 61 and 62 having different gear diameters, and an auxiliary transmission clutch 63. The sub-transmission clutch 63 performs a shift by switching between a state where power is transmitted by the gear 61 and a state where power is transmitted by the gear 62. The power changed in the auxiliary transmission 60 is transmitted to the differential mechanism 65 via the auxiliary transmission output shaft 64.

  The differential mechanism 65 distributes the power transmitted from the auxiliary transmission 60 to the left and right. The power distributed by the differential mechanism 65 is transmitted to the left and right rear wheels 13, respectively.

  Next, with reference to FIG.3 and FIG.4, the operation tool arrange | positioned inside the cabin 22 is demonstrated. FIG. 3 is a plan view showing an operation tool provided in the cabin 22. FIG. 4 is a block diagram showing a configuration for controlling the HMT 17.

  As shown in FIG. 3, a driver seat 70 is disposed inside the cabin 22. A shift lever (vehicle speed operation unit) 71 and a speed adjustment dial (vehicle speed operation unit) 72 are arranged on the right side of the driver seat 70. As shown in FIG. 4, the tractor 10 includes a shift lever sensor 71 a, a dial sensor 72 a, and a transmission control unit (control unit) 100 that controls the HMT 17.

  The transmission lever 71 is an operating tool for setting the set vehicle speed (maximum vehicle speed) of the tractor 10. The transmission lever 71 is configured to be slidable in the front-rear direction. The shift lever sensor 71 a detects the position of the shift lever 71 and outputs it to the transmission control unit 100. The transmission control unit 100 changes the inclination angle of the movable swash plate 31a based on the input content to perform a shift.

  The speed adjustment dial 72 is an operation tool for adjusting the set vehicle speed set by the speed change lever 71. The speed adjustment dial 72 of the present embodiment can be adjusted in two steps, low speed and high speed, but the vehicle speed may be adjusted steplessly. The dial sensor 72 a detects whether the setting of the speed adjustment dial 72 is low speed or high speed and outputs it to the transmission control unit 100. The transmission control unit 100 controls the auxiliary transmission clutch 63 based on the input content, and causes the vehicle body 11 to travel at the set vehicle speed.

  A clutch pedal 73 and a brake pedal 74 are disposed below the driver seat 70. Further, the tractor 10 includes a clutch pedal switch 73a, a potentiometer (depression amount detection unit) 74a, and a brake pedal switch (auxiliary depression amount detection unit) 74b.

  The clutch pedal 73 is an operating tool for switching between a transmission state in which the output of the engine 15 is transmitted to the rear wheel 13 side and a cutoff state in which the output is blocked. The clutch pedal switch 73a detects whether or not the depression amount of the clutch pedal 73 is equal to or greater than a predetermined threshold value, and outputs the detected value to the transmission control unit 100. The transmission control unit 100 switches between the transmission state and the cutoff state by controlling the high speed side clutch 51 and the low speed side clutch 52 in accordance with the depression amount (rotation angle) of the clutch pedal 73.

  The brake pedal 74 includes a left brake pedal and a right brake pedal, and can perform braking by operating the brakes 80 disposed on the left rear wheel and the right rear wheel, respectively. The potentiometer 74a detects the depression amount of the brake pedal 74 and outputs it to the transmission control unit 100. When it is not necessary to brake the left and right rear wheels separately, the left brake pedal and the right brake pedal are connected by a connection plate (not shown). The brake pedal switch 74b detects whether or not the amount of depression of the brake pedal 74 is greater than or equal to a threshold value (first threshold value described later) and outputs the detected value to the transmission control unit 100. In addition, the potentiometer 74a and the brake pedal switch 74b may be attached to both the left brake and the right brake, or may be attached to only one of them.

  When the amount of depression of the brake pedal 74 is greater than or equal to the first threshold, the transmission control unit 100 controls the operation of the movable swash plate 31a or operates the brake 80 to brake the tractor 10. The angle of the movable swash plate 31a may be detected by a sensor, or may be estimated from the ratio between the vehicle speed and the engine speed. Further, the transmission control unit 100 according to the present embodiment changes “deceleration” that is “a reduction amount of the vehicle speed per unit time” according to the depression amount of the brake pedal 74. Note that how to adjust the vehicle speed according to the depression amount of the brake pedal 74 will be described later.

  In front of the driver's seat 70, a steering wheel 75 for an operator to switch the traveling direction of the tractor 10 is disposed. In the vicinity of the steering 75, a reverser lever 76 and a work implement lifting lever 77 are disposed. The tractor 10 includes a reverser lever switch 76a.

  The reverser lever 76 is an operating tool for switching between forward and backward movement of the tractor 10. The reverser lever switch 76a detects whether the position of the reverser lever 76 is the forward position or the reverse position, and outputs the detected position to the transmission control unit 100. The transmission control unit 100 switches the forward and backward movements of the tractor 10 by switching the reverse clutch 56 based on the input content.

  The work implement lifting lever 77 is an operation tool for raising and lowering the work implement. When the operator operates the work implement lifting lever 77, the operation is detected by a sensor (not shown). The work implement can be moved up and down by operating the work implement lifting mechanism 21 in accordance with the detection result output by the sensor.

  In addition, the vehicle speed is input from the vehicle speed sensor 78 and the engine speed (engine speed) is input from the engine speed sensor 79 to the transmission control unit 100.

  Next, with reference to FIGS. 5 to 7, control (hereinafter referred to as deceleration adjustment control) for adjusting the deceleration based on the depression amount of the brake pedal 74 (hereinafter referred to as the depression amount) will be described. FIG. 5 is a flowchart illustrating vehicle speed adjustment control performed by the transmission control unit 100.

  When the transmission control unit 100 acquires the depression amount from the potentiometer 74a (S101), the transmission control unit 100 determines whether or not the depression amount is equal to or greater than the first threshold (S102). The first threshold value is a value that defines a play portion of the brake pedal 74. Therefore, the first threshold value is preferably a value with a relatively small amount of depression. If the transmission control unit 100 determines that the amount of depression is smaller than the first threshold, for example, the process of S101 is performed again after a predetermined time.

  The transmission control unit 100 determines whether the brake pedal switch 74b is ON or OFF when it is determined that the depression amount is equal to or greater than the first threshold value. If the amount of depression is greater than or equal to the first threshold, the brake pedal switch 74b should be turned on. When the brake pedal switch 74b is OFF, the transmission control unit 100 determines that there is a problem with the potentiometer 74a or the brake pedal switch 74b (S104). Thereafter, the transmission control unit 100 sets the deceleration to the upper limit in order to operate the tractor 10 to the safe side (S105). Thereby, the tractor 10 can be stopped quickly. It should be noted that the upper limit may not be used as long as the deceleration is made larger than when there is no problem.

  If the brake pedal switch 74b is ON, the transmission control unit 100 determines whether or not the depression amount is equal to or greater than the second threshold (S106). If the amount of depression is less than the second threshold, the transmission control unit 100 calculates a deceleration based on the amount of depression (S107). As described above, the deceleration is a reduction amount of the vehicle speed per unit time. FIG. 6 shows a correspondence relationship between the depression amount and the deceleration. This correspondence relationship is stored in the transmission control unit 100 or another device. This correspondence is set in advance, but the value can be changed by the setting of the manufacturer or operator of the tractor 10. As shown in FIG. 6, the deceleration is set to increase as the depression amount of the brake pedal 74 increases. In other words, the tractor 10 stops more rapidly as the brake pedal 74 is depressed to the back.

  The transmission control unit 100 calculates the deceleration considering the detected depression amount and the content of the graph of FIG. 6 (S107), and controls the HMT 17 so that the deceleration is realized (S108). ). After that, the transmission control unit 100 performs the processes after S101 again. When the depression amount of the brake pedal 74 changes, the depression amount is updated to calculate a new deceleration (S107), and the HMT 17 is controlled by the deceleration (S108). As a result, the operator can decelerate the vehicle speed so as to follow his / her intention only by adjusting the depression amount of the brake pedal 74.

  In addition, since there is a limit in controlling the HMT 17 to perform rapid braking, when the amount of depression is equal to or greater than the second threshold, the clutch is turned off and rapid braking is performed by the brake 80 (S109). When the clutch is turned off, the power of the engine 15 is transmitted to the HMT 17 but not transmitted to the differential mechanism 65 and the rear wheel 13. Even when it is determined that there is a problem with the potentiometer 74a or the brake pedal switch 74b, the clutch may be turned off to perform rapid braking.

  Thereby, as shown in FIG. 7, the tractor 10 of the structure decelerated quickly as the depression amount becomes large is realizable.

  In the above description, the vehicle speed is controlled based on the depression amount of the brake pedal 74. However, similar control can be performed on the clutch pedal 73 based on the depression amount. In this case, a depression amount detection unit such as a potentiometer is disposed on the clutch pedal 73. The transmission control unit 100 controls the vehicle speed based on the depression amount of the clutch pedal 73 in the same manner as described above. The vehicle speed may be controlled based on the depression amount of only one of the clutch pedal 73 and the brake pedal 74, or the vehicle speed may be controlled based on the depression amounts of both the clutch pedal 73 and the brake pedal 74. good.

  Next, a second embodiment will be described with reference to FIG. In the description of the second embodiment, components that are the same as or similar to those in the above embodiment may be given the same reference numerals in the drawings to simplify the description.

  The transmission 82 according to the second embodiment is a hydraulic-mechanical continuously variable transmission that performs a shift without using a planetary gear mechanism. The transmission 82 may be a hydrostatic continuously variable transmission (HST). The transmission 82 is an inline transmission that includes an input shaft 81 to which power of the engine 15 is input and a cylindrical output shaft 83 that is disposed outside the input shaft.

  The output of the output shaft 83 is transmitted to the forward clutch 86 via the gear 84 and the forward rotation gear 85. The output of the output shaft 83 is transmitted to the reverse clutch 89 via the gear 84, the counter shaft 87 and the reverse gear 88. By controlling the forward clutch 86 and the reverse clutch 89, the rotation direction of the transmission shaft 90 can be switched.

  The sub-transmission device 60 includes gears 61 and 62 having different diameters as in the present embodiment, and transmits the power of the transmission shaft 90 to the sub-transmission shaft 92 via any one of the gears. The power transmitted to the auxiliary transmission shaft 92 is transmitted to the rear wheel 13 via the differential mechanism 65 and also to the front wheel 12 via a differential mechanism for front wheels (not shown).

  As described above, the tractor 10 according to the embodiment includes the engine 15, the HMT 17, the front wheels 12 and the rear wheels 13, the potentiometer 74a, and the transmission control unit 100. The HMT 17 changes the output of the engine 15. The front wheel 12 and the rear wheel 13 cause the vehicle body 11 to travel by the output of the HMT 17. The potentiometer 74a detects the amount of depression of the brake pedal 74. The transmission control unit 100 controls the HMT 17 based on the amount of depression detected by the potentiometer 74a so as to increase the value as the amount of depression increases, thereby reducing the vehicle speed.

  Thereby, since deceleration can be adjusted based on the depression amount of the brake pedal 74, the tractor 10 can be stopped at a desired position.

  Further, in the tractor 10 of the above-described embodiment, the transmission control unit 100 is connected to the power transmitted from the engine 15 to the HMT 17 (particularly the planetary gear mechanism 40) when the amount of depression is equal to or greater than the predetermined second threshold. To reduce the vehicle speed.

  Thereby, for example, the tractor 10 can be stopped while maintaining the power transmitted from the engine 15 to the HMT 17.

  The tractor 10 according to the embodiment includes a brake 80 that brakes the front wheel 12 and the rear wheel 13. The transmission control unit 100 shuts off the power transmitted from the engine 15 to the front wheels 12 and the rear wheels 13 and operates the brake 80 when the depression amount is equal to or greater than the second threshold value.

  Thereby, since the deceleration by the HMT 17 has a limit, the tractor 10 can be suddenly stopped by using the brake 80 as described above.

  In addition to the potentiometer 74a, the tractor 10 of the above embodiment includes a brake pedal switch 74b that detects the amount of depression of the brake pedal 74 by a method (configuration) different from that of the potentiometer 74a. The transmission control unit 100 increases the deceleration when the detection result of the potentiometer 74a does not match the detection result of the brake pedal switch 74b.

  Thereby, the malfunction of the potentiometer 74a can be detected. Furthermore, when the potentiometer 74a has a problem, it can be operated on the safe side.

  Although the embodiment and the modification of the present invention have been described above, the above configuration can be modified as follows, for example.

  In the HMT 17 of the first embodiment, the output of the engine 15 and the output of the HST 30 are combined in the planetary gear mechanism 40, and the combined output is transmitted to the HMT output shaft 48. In this regard, the HMT 17 may be configured to be able to switch between transmitting the synthesized output to the HMT output shaft or outputting the HST output directly to the HMT output shaft.

  In the above, only the hydraulic pump 31 is a variable displacement type, but the hydraulic motor 32 may be a variable displacement type, and both the hydraulic pump 31 and the hydraulic motor 32 may be a variable displacement type.

  In the above description, the control in the state where the left brake pedal and the right brake pedal are connected has been described. However, the above control may be performed separately for the left brake pedal and the right brake pedal.

  In the above description, the depression amount of the brake pedal 74 is detected by the potentiometer 74a, but the depression amount may be detected by another sensor (such as a pressure sensor).

  The transmission control unit 100 may be provided inside an ECU (engine control unit), or may be provided separately from the ECU.

  The present invention is not limited to a four-wheel tractor, and can be applied to, for example, a semi-crawler tractor. It can also be applied to work vehicles other than tractors (rice transplanters, etc.).

10 Tractor (work vehicle)
11 body 12 front wheel (traveling part)
13 Rear wheel (travel section)
15 engine 17 HMT (continuously variable transmission)
30 HST
40 planetary gear mechanism 74 brake pedal 74a potentiometer (depression amount detection unit)
74b Brake pedal switch (auxiliary depressing amount detection unit)
80 Brake 100 Transmission control unit (control unit)

Claims (4)

Engine,
A hydraulic continuously variable transmission for shifting the output of the engine;
A traveling unit that causes the vehicle body to travel by the output of the continuously variable transmission,
A depression amount detector for detecting the depression amount of the brake pedal or clutch pedal;
When the amount of decrease in vehicle speed per unit time is referred to as deceleration, the deceleration calculated so that the value increases as the depression amount increases based on the depression amount detected by the depression amount detection unit And a controller for controlling the continuously variable transmission to decelerate the vehicle speed,
A work vehicle comprising: The work vehicle according to claim 1,
The said control part is a work vehicle characterized by decelerating a vehicle speed in the state which connected the power transmitted from the said engine to the said continuously variable transmission, when the said depression amount becomes more than a predetermined threshold value. The work vehicle according to claim 1 or 2,
A brake for braking the traveling unit;
The control unit cuts off power transmitted from the engine to the traveling unit and operates the brake when the stepping amount is equal to or greater than a predetermined threshold value. A work vehicle according to any one of claims 1 to 3,
In addition to the depression amount detection unit, an auxiliary depression amount detection unit that detects the depression amount of the brake pedal or the clutch pedal by a method different from the depression amount detection unit,
When the detection result of the stepping amount detection unit and the detection result of the auxiliary stepping amount detection unit do not match, the control unit decelerates the vehicle speed at the deceleration larger than the calculated deceleration. Work vehicle.

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