JP6561601B2 - Work vehicle - Google Patents

Description

  The present invention relates to a traveling transmission device in a work vehicle such as a tractor in which a work device such as a tillage device is connected to a rear portion.

  Rotational drive output from the engine is appropriately decelerated via a plurality of gears of the multi-stage transmission and transmitted to the drive wheels. By changing the combination of the gears, There is a known technique for reducing a shift shock by providing a clutch capable of adjusting the speed in series with a multi-stage transmission and reducing the clutch pressure at the time of shifting and gradually increasing the vehicle speed by changing the vehicle speed at the time of shifting (patent) Reference 1).

JP 2014-134291 A

  However, in the invention described in the above-mentioned patent document, during high load traveling such as tillage by plow towing, the speed drops suddenly at the moment when the clutch pressure decreases, so that the shift feeling becomes worse, for example, a shock is generated at the time of shifting. It was the cause. In addition, it has been required to have a configuration that can be adjusted so that the shift can be performed more smoothly when shifting at low loads such as on the road.

To solve the problems described above, the present invention provides a mechanical transmission to shift the rotational drive output from the engine in multiple stages, and a hydraulic clutch for transmitting or interrupting a driving force transmission by the multistage transmission, a control unit for controlling the clutch pressure of the hydraulic clutch, after the control unit reduces the pressure in the clutch pressure during a shift to the neutral pressure so as not to power transmission, the connection pressure before vacuum from a neutral pressure at connection time defined In a traveling transmission device for a work vehicle having a standard boosting pattern for boosting up to, a boosting adjustment dial is provided, and the adjustment value by the boosting adjustment dial corresponds to the connection time adjustment region, the standard boosting region, and the connection pressure adjustment region. The control unit boosts the standard boosting pattern when the standard boosting region is selected, and the standard boosting when the control unit is the connection time adjusting region. Boosted by the step-up pattern obtained by changing the turn the connection time, that when the a connection pressure adjusting region is boosted by the boost pattern obtained by translating the standard boost pattern to the high pressure side or low pressure side First feature.

Further, the present invention provides the oil temperature sensor for measuring the hydraulic oil temperature of the hydraulic clutch in the invention having the first feature, and when the oil temperature is equal to or lower than a predetermined temperature, A second feature is that the voltage is boosted by the standard boost pattern .
Further, in the invention having the first feature or the second feature, the present invention is a third feature in which, when the boost adjustment dial is at the maximum position, the control unit shifts without reducing pressure. And

  According to the invention having the first feature, it is possible to adjust the time for pressure increase to the connection pressure after the hydraulic clutch is lowered to the neutral pressure by the pressure increase adjustment dial. It is possible for the operator to change the speed change feeling according to the situation and preference, such as increasing the pressure in a long time during low load traveling.

Further , by adjusting the boost pattern with the boost adjustment dial by switching between the change of the boost time and the parallel movement of the boost pattern according to the adjustment value, it is possible to perform an appropriate shift feeling adjustment according to the situation.

According to the invention having the second feature, in addition to the effect of the invention having the first feature, the hydraulic clutch hydraulic oil changes in viscosity depending on the temperature. Adjustment may not be performed normally, and the shift feeling may deteriorate against the driver's will. This can be prevented by ignoring the adjustment value when the oil temperature falls below a predetermined temperature.
Further, according to the invention having the third feature, it is possible to shift without a shock in the case of high load work.

Side view of the entire tractor Transmission system development diagram of traveling transmission Control block diagram of the entire tractor Hydraulic circuit diagram of tractor Cross section of forward / reverse clutch Timing chart showing movement of each clutch Perspective view around the main transmission lever The figure which shows the change of the adjustment position of the boost adjustment dial and the boost curve of the forward / reverse clutch

  An embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a riding tractor as an example of a work vehicle. An engine room covered with a bonnet 2 is arranged at the front of the traveling vehicle body 1, and an engine E is mounted therein. The rotational power of the engine E is transmitted to the traveling transmission device in the transmission case 3, and the rotational power decelerated by the traveling transmission device is transmitted to the front wheels 4 and the rear wheels 5.

  A driver's seat 7 is installed in the cabin 6 at the rear of the vehicle body, and a steering handle 8 for steering the front wheels 4 and 4 is provided in front of the driver's seat 7. A meter panel 9 is installed on the front side of the steering handle 8. At the rear of the tractor body, a rotary working machine or the like is installed, but is driven by a PTO shaft 111 protruding rearward from the mission case 3.

  As shown in FIG. 2, the power transmission mechanism in the transmission case will be described. The rotation of the output shaft 20 of the engine E is transmitted to the input shaft 21, and the first input gear 22 and the second input gear 23 fixed to the input shaft. Are the first low speed gear 26 of the first high / low clutch 24 and the second low speed gear 27 of the second high / low clutch 25 and the first high speed gear 30 of the first high / low clutch 24 and the second high / low clutch, respectively. The second high-speed gear 31 is engaged with the 25 high-speed gears 31 and is driven to rotate.

  The first high / low clutch 24 and the second high / low clutch 25 are the same hydraulic multi-plate clutch, and each of the first clutch shafts decelerates the rotation of the input shaft 21 to two stages of high and low at the same reduction ratio. 28 and the second clutch shaft 29 are transmitted.

  The rotation of the low-speed transmission shaft 34 and the high-speed transmission shaft 32 is transmitted to the first sync change 42 and the second sync change 36, respectively, and the first sync small gear 43 and the second sync small gear 37 are the fifth of the first transmission shaft 39. The first synchro large gear 44 and the second synchro large gear 38 are meshed with the sixth gear 41 of the first transmission shaft 39 to be transmitted. As a result, the rotation of the first input shaft 21 is shifted by the first transmission shaft 39 between the low speed 4 speed and the high speed 4 speed.

  The multi-speed transmission 150 up to this point constitutes the main transmission unit, reads the shift position of the main transmission lever 15 operated by the operator, and the traveling ECU 120 automatically performs the first / second high / low hydraulic multi-plate clutch. 24, 25 and the first and second sync change 36, 42 are controlled to shift the speed to 4 speeds and 4 speeds.

  The first transmission shaft 39 is connected to the second transmission shaft 45, and the seventh gear 46 and the eighth gear 47 are fixed to the second transmission shaft 45, and the forward rotation clutch gear 49 and the reverse rotation shaft of the forward / reverse clutch 48. The reverse rotation gear 51 is engaged with the reverse rotation clutch gear 50. Therefore, when the forward / reverse clutch 48 is connected to the forward clutch gear 49, the forward transmission state is transmitted to the auxiliary transmission shaft 53 connected to the reverse rotation clutch 48, and when the forward / reverse clutch 48 is connected to the reverse rotation clutch gear 50, the reverse rotation state is established. It is transmitted to the auxiliary transmission shaft 53.

  A ninth gear 54 and a tenth gear 55 are fixed to the auxiliary transmission shaft 53 and mesh with the third synchro small gear 56 and the third synchro large gear 59 of the third sync change 58, respectively. When the third sync change 58 is connected to the third sync small gear 56 side, the fifth transmission shaft 60 is accelerated by the rotation transmitted from the ninth gear 54 to the third sync small gear 56, and is driven at a high speed. When the synchro change 58 is connected to the third synchro large gear 59, the fifth transmission shaft 60 is decelerated by the rotation transmitted from the tenth gear 55 to the third synchro large gear 59 and driven at a medium speed.

  When the third sync change 58 is made neutral, the rotation of the tenth gear 55 is transmitted to the third synchro large gear 59, and transmitted from the eleventh gear 57 fixed to the third synchro small gear 59 side to the fourth synchro small gear 69. It has come to be.

  When the fourth sync change 71 is connected to the fourth sync small gear 69 side, the rotation of the fourth sync small gear 69 is rotated by the rotation of the sixteenth gear 74, and the fourth sync change 71 is changed to the fourth sync big gear 72. When connected to the side, the rotation of the fourth sync small gear 69 is transmitted from the fifteenth gear 70 to the seventeenth gear 75, the eighteenth gear 76, and the fourth synchro large gear 72, and the sixteenth gear 74 becomes ultra-low speed.

  Further, the sixteenth gear 74 meshes with the twelfth gear 61 fixed to the fifth transmission shaft 60 to drive the fifth transmission shaft 60. The first bevel gear 62 fixed to the shaft end of the fifth transmission shaft 60 meshes with the second bevel gear 63 of the rear bevel gear case 64, and the 13th gear 66 and the 14th gear 67 from the bevel output shaft 65 of the rear bevel gear case 64. , The rear wheel output shaft 68 is rotated to drive the rear wheel 5.

  Further, a 21st gear 117 is fixed to the fifth transmission shaft 60, and a first front wheel is connected via a 22nd gear 118 and a 23rd gear 148 fixed to a third tube shaft 119 supported by the auxiliary transmission shaft 53. Transmission to the 19th gear 77 of the drive shaft 78 is transmitted to the first front wheel drive shaft 78 by the rotation of the fifth transmission shaft 60 at low speed 16 stages and high speed 16 stages.

  The power is transmitted from the first front wheel drive shaft 78 to the second front wheel drive shaft 85 via the front wheel speed increasing clutch 79 and is transferred to the third front wheel drive shaft 86, the fourth front wheel drive shaft 87, and the front wheel drive bevel shaft 88. The first front bevel gear 89 fixed to the shaft end of the front wheel drive bevel shaft 88 meshes with the second front bevel gear 115 of the front bevel case 90, and the front bevel output shaft 91 of the front bevel case 90 to the first front bevel gear 92 The front wheel output shaft 94 is rotated via the front wheel drive shaft 116 and the second bevel gear set 93 to drive the front wheel 4.

  When the front wheel speed increasing clutch 79 is connected to the front wheel constant speed gear 82 side, the rotational driving of the first front wheel driving shaft 78 is transmitted to the second front wheel driving shaft 85 as it is, and normal four wheel driving is performed. When connected to the front wheel speed increasing gear 84 side, the rotational drive of the first front wheel drive shaft 78 is increased from the front wheel constant speed gear 82 through the first speed increasing gear 81 and the second speed increasing gear 83 to the second speed. It is transmitted to the front wheel drive shaft 85 to achieve front wheel acceleration four-wheel drive. Further, when the front wheel acceleration clutch 79 is set to the neutral state, power is not transmitted to the front wheel 4, so that the rear wheel is driven by two wheels.

  The main clutch gear 96 of the PTO main clutch 97 is meshed with the second input gear 23 so that the PTO main clutch 97 performs power connection to the PTO output shaft 111.

  The first PTO shaft 95 is provided with a PTO speed change portion 157, and the first PTO gear 98, the second PTO gear 99, the fifth synchro small gear 100 of the fifth sync change 151, and the fifth synchro large gear 101 are mounted on the first PTO gear 95. A twentieth gear 102, a twenty-fourth gear 152, a twenty-sixth gear 103, and a twenty-fifth gear 153 are fixed to the shaft 107, and a PTO reverse gear 105 is pivotally supported on the counter shaft 106.

  When the first PTO gear 98 is slid and meshed with the twentieth gear 102, the second PTO shaft 107 becomes the second speed, and when the first PTO gear 98 is slid and engaged with the second PTO gear 99, the first PTO shaft 95 rotates. Is transmitted to the second PTO shaft 107 via the second PTO gear 99 and the 24th gear 152 to become the fourth speed, and when the fifth sync change 151 is connected to the fifth sync small gear 100, the fifth sync small gear 100 to the 26th gear. When the fifth synchro change gear 151 is connected to the fifth synchro large gear 101, the fifth synchro gear 101 is transmitted from the fifth synchro large gear 101 to the 25th gear 153, and the third gear is set. When meshed with the 1PTO gear 98 and the twentieth gear 102, the rotation of the first PTO shaft 95 is changed from the first PTO gear 98 to the PTO reverse gear 10. A reverse rotation transmitted to the 2PTO shaft 107 is transmitted to the 20th gear 102 through.

  The rotation of the second PTO shaft 107 is transmitted to the fourth PTO shaft 108 via the third PTO shaft 156, and is further decelerated by the first PTO output gear 109 and the second PTO output gear 110 to drive the PTO output shaft 111.

  FIG. 3 is a control block diagram for controlling the operation of each part of the tractor, and controls the rotation of the engine ECU 190 for controlling the output of the engine E, the work machine lifting system ECU 191 for controlling the lifting and lowering of the work machine, the front wheels 4 and the rear wheels 5. And a traveling system ECU 120 that controls the traveling speed, and communicates control signals by CAN communication.

  Input of control data to the engine ECU 190 includes a selection mode from the engine mode selection switch 192, an exhaust temperature from the engine exhaust temperature sensor 207, a rotation speed of the engine output shaft 20 from the engine rotation sensor 121, and an engine oil pressure. From the engine ECU 190, the oil pressure from the sensor 193, the radiator water temperature from the engine water temperature sensor 194, the fuel pressure of the common rail from the rail pressure sensor 198, the depression signal of the accelerator pedal 18 of the accelerator operation position detection sensor 195, etc. The control outputs are the rail pressure to the fuel high-pressure pump 196 and the injection signal to the high-pressure injector 197.

  The control data input to the work implement elevating system ECU 191 includes an operation signal from the position control sensor 199 by the position control lever 13 for raising and lowering the work implement, a lift position signal from the lift arm sensor 200, and a raised position restriction dial. The control output from the work implement elevating system ECU 191 based on the adjustment signals of 201 and the lowering speed adjustment dial 202 is an ascending or descending signal to the main raising solenoid 204 and the main lowering solenoid 205 of the hydraulic raising / lowering cylinder.

  Input of control data to the travel system ECU 120 is the first clutch Lo side pressure switch 122, the first clutch Hi side pressure switch 123, the second clutch Lo side pressure switch 124, the second clutch Hi side pressure switch 125, and the forward clutch pressure. Each signal of the sensor 128 and the boost adjustment dial 129, the operation position of the forward / reverse lever operation position sensor 130 of the forward / reverse lever 11, the operation position of the auxiliary transmission position sensor 131 of the auxiliary transmission lever, and the main transmission of the main transmission lever 15 The operation position of the lever position sensor 136, the oil temperature of the oil temperature sensor 133 of the oil in the mission case, the shift positions of the first main transmission mechanism position sensor 137 and the second main transmission mechanism 138, and the left and right of the brake connection detection switch 139 Of the brake pedals 12L and 12R and the traveling speed of the vehicle speed sensor 140 The rotation speed of the PTO rotational sensor 220, and the on-off signal of the PTO switching on and off switches 221, PTO automatic - a switching signal of the manual selector switch 222, traveling - a switching signal or the like of the work changeover switch 223.

  The control output from the traveling system ECU 120 includes a forward switching solenoid 141F and a reverse switching solenoid 141R, a forward / reverse boosting solenoid 142, a first main transmission first solenoid 207, a first main transmission second solenoid 208, and a second main transmission first. 1 solenoid 209, second main speed change second solenoid 210, first Lo side solenoid 211a, first Hi side solenoid 211b, second Lo side solenoid 212a, second Hi side solenoid 212b, 4WD solenoid 213, front wheel speed increasing solenoid 214 A buzzer 215, a PTO clutch solenoid 216, and the like.

  FIG. 4 is a diagram showing a hydraulic circuit of the tractor. The main pump 250 and the sub pump 251 that are operated by engine power suck up the lubricating oil in the transmission case 3 through the suction filter 252, and pressure oil is supplied as hydraulic oil to the hydraulic circuit. Pressure oil is supplied from the sub pump 251 to the power steering device 253, and the front wheels 4 are operated. The hydraulic oil discharged from the power steering device 253 is used as lubricating / cooling oil for the first high / low clutch 24, the second high / low clutch 25, and the forward / reverse clutch 48, and returned to the mission case 3. It is.

  Pressure oil is supplied from the main pump 250 to the work machine hydraulic device 254 and the traveling hydraulic device 255. When the main transmission lever 15 is operated to the first speed, a current flows through the first main transmission first solenoid 207 to move the valve, and the pressure oil is released from the Lo side oil chamber 256L of the first main transmission cylinder 256, The first sync change 42 is connected to the first sync small gear 43 side. Further, a current flows through the first Lo-side solenoid 211a, the valve moves, pressure oil is supplied to the low-speed side oil chamber of the first high / low clutch 24, and is connected to the first low-speed gear 26 side.

  When the main transmission lever 15 is operated from the first speed to the second speed, the state of the first main transmission first solenoid 207 does not change, and the first sync change 42 is connected to the first sync small gear 43 side, Current flows through the first Lo side solenoid 211a and the first Hi side solenoid 211b to move the respective valves, and pressure oil is supplied to the oil chamber on the high speed side of the first high / low clutch 24 and connected to the first high speed gear 30 side. Is done.

  When the main speed change lever 15 is operated from the second speed to the third speed, the current of the first main speed change first solenoid 207 stops, the current flows to the second main speed change first solenoid 209, and the first sync change 42 Is disconnected, and the second sync change 36 is connected to the second sync small gear 37 side. Furthermore, the current of the first Hi side solenoid 211b is stopped, the current is passed to the second Lo side solenoid 212a, the respective valves move, and pressure oil is supplied to the oil chamber on the low speed side of the second high / low clutch 25, It is connected to the second low speed gear 27 side.

  Similarly, in the fourth speed, the second sync small gear 37 and the second high speed gear 31, in the fifth speed, the first sync large gear 44 and the first low speed gear 26, and in the sixth speed, the first sync large gear 44 and the first high speed gear. In the 30th and 7th speeds, the second synchro large gear 38 and the second low speed gear 27 are connected, and in the 8th speed, the second synchro large gear 38 and the second high speed gear 31 are connected to perform the main speed change operation.

  The connection pressure of the forward / reverse clutch 48 is adjusted during these shifts and when the vehicle starts, so that shift shocks and shocks when starting are suppressed. When the forward / backward lever 14 is moved forward or backward, the forward / backward lever sensor 130 reads the operation position, an electric current is supplied to the forward switching solenoid 141F or the reverse switching solenoid 141R, the valve moves, and the oil path is selected. The A configuration in which the pressure of the forward / reverse oil passage 142b can be adjusted to an arbitrary pressure by adjusting the flow rate that determines the relief pressure of the forward / reverse relief valve 142a according to the magnitude of the current flowing to the forward / backward boost solenoid 142, which is a proportional solenoid. It has become.

  FIG. 5 is a cross-sectional view of the forward / reverse clutch 48. The clutch shaft 48a integrated with the forward rotation clutch gear 49 is rotatably supported on the auxiliary transmission shaft 53 by the second bearing B1 and the third bearing B2, and has a plurality of inner clutch plates 48b at the rear. doing. The rear portion of the clutch shaft 48a is covered with a clutch case 48d, and a presser plate 48e fixed to the inside of the front portion of the clutch case 48d is positioned in front of the front ends of the plurality of inner clutch plates 48b.

  A plurality of outer clutch plates 48c are alternately arranged inside the clutch case 48d so as to be sandwiched between the inner clutch plates 48b, and the inner clutch plates 48b have a plurality of teeth on the inner side. The outer clutch plate 48c rotates integrally with the shaft 48a and rotates integrally with the clutch case 48d because the outer clutch plate 48c has a plurality of teeth on the outside.

  The clutch case 48d has a clutch piston 48f at the rear part of the clutch shaft 48a and is urged rearward by a spring 48g. The rear part of the clutch piston 48f has a space for a cylinder part 48h to which pressure oil is supplied. . The forward / rearward clutch 48 is supplied with pressure oil to the cylinder portion 48h. When the pressure exceeds the elastic force of the spring 48g, the clutch piston 48f moves forward, and the inner clutch plate 48b and the outer clutch plate 48c are moved between the presser plate 48e. Squeeze. The inner clutch plate 48b and the outer clutch plate 48c, which have been pressed, transmit the driving force to each other by friction, and the driving force transmitted from the forward clutch gear 49 is transmitted to the clutch case 48d, which is splined to the clutch case 48d. The sub-transmission shaft 53 that is fitted rotates.

  When no pressure oil is supplied to the cylinder portion 48h and no pressure is applied, the clutch piston 48f is pushed rearward by the elastic force of the spring 48g, so that the inner clutch plate 48b and the outer clutch plate 48c are not pressed. In this state, since the inner clutch plate 48b and the outer clutch 48c do not transmit driving force to each other, the PTO clutch 48 is in a state of interrupting power transmission, and the auxiliary transmission shaft 53 does not rotate even if the forward clutch gear 49 rotates. . A reverse clutch gear 50 is provided on the opposite side of the clutch case 48d, and the reverse drive power is transmitted and cut off with the same configuration.

  FIG. 6 is a timing chart showing the movement of each clutch when the main gear shift is operated from the first speed to the second speed. When the forward / reverse lever 14 is moved forward and the main transmission lever 15 is moved to the second speed while traveling forward at the first speed, the first high / low clutch 24 is switched from the low speed side to the high speed side, and at this time the forward / backward clutch is moved forward. The pressure is reduced to such a low level that power is not transmitted once, and the pressure is gradually increased to reduce the shift shock. On the other hand, the second high / low clutch 25 is neutral, the first main transmission cylinder is connected with the first sync change 42 to the first sync small gear 43, and the second main transmission cylinder 257 is ready for the third speed. The second sync change 36 is connected to the second sync small gear 37. In this case, the lever operation time t3 includes an operation completion determination time t4 based on the moving speed, and the first relevant clutch starts to be connected after the lever operation time t3 and the clutch piston moving time t1, and before the predetermined time t5 (approximately) 10 ms before), the forward / reverse clutch 48 is turned off to prevent double biting. Similarly, during other shifts and when the vehicle starts, the forward / reverse clutch 48 is adjusted so as to gradually increase the pressure, thereby reducing the shock during driving.

  FIG. 7 is a perspective view around the main transmission lever 15. The main shift lever 15 has a manual shift range 15s, a neutral range 15n, and an automatic shift range 15d according to the shift position, and the manual shift range 15s can be manually shifted from 1st to 8th speed. An appropriate gear combination is automatically selected and connected by the control unit at the shift position. In the neutral range 15n, power transmission of the multi-stage transmission 150 is interrupted, and when the lever is operated in the automatic shift range 15d, the shift is automatically performed according to the accelerator state. The step-up adjustment dial 129 is provided on the lever guide on the right side of the driver's seat, and is configured to adjust the shift sensitivity by adjusting the step-up characteristic of the forward / reverse clutch 48.

  FIG. 8 is a diagram showing changes in the adjustment position of the boost adjustment dial 129 and the boost curve 300 of the forward / reverse clutch 48. When the dial position is the standard boosting region 129n, the boosting is performed according to the standard boosting curve 300n stored in advance in the traveling system ECU 120 as the control unit. When the dial position is the high-pressure side connection pressure adjustment region 129h, the standard boost curve 300n is boosted according to the high-pressure adjustment boost curve 300h that is translated to the high-pressure side according to the dial position. When the pressure increase adjustment dial 129 is turned to the maximum position, the pressure is adjusted by the maximum pressure line 300 m and no pressure reduction is performed.

  When the dial position is in the low-pressure side connection pressure adjustment region 129h, the standard boost curve 300n is boosted according to the low-pressure adjustment boost curve 300l that is translated to the low pressure side according to the dial position. Further, when the dial position is the connection time adjustment area 129o, the connection time is adjusted from the specified connection time t10 of the standard boost curve 300n to the adjustment connection time t11 according to the dial position, so that the connection is adjusted gently. The voltage is boosted according to the time-adjusted boost curve 300o.

  With these adjustments, for example, in the case of high-load work such as plow plowing, it is possible to set the clutch so that the forward / reverse clutch 48 can be quickly connected so that the gear can be smoothly shifted or started. It is possible to adjust according to preference so that the forward / reverse clutch 48 is loosely connected and can be shifted and started without shock.

  Further, the travel system ECU 120 acquires the hydraulic oil temperature of the hydraulic clutch by the oil temperature sensor 133, and when the oil temperature is equal to or lower than a certain temperature, the pressure is increased according to the standard boost curve 300n regardless of the dial position of the boost adjustment dial 129. Is done. For example, hydraulic oil having a characteristic that the viscosity changes greatly around 20 degrees may be used. Therefore, if the pressure increase curve is changed below a predetermined oil temperature, the clutch may not operate normally. If the oil temperature is below a certain temperature, this can be prevented by not changing the boosting curve.

E Engine t10 Specified connection time 48 Forward / reverse clutch (hydraulic clutch)
120 Traveling ECU (control unit)
129 Step-up adjustment dial 129n Standard step-up region 129l Low-pressure side connection pressure adjustment region 129h High-pressure side connection pressure adjustment region 129o Connection time adjustment region 150 Multi-stage transmission 300n Standard step-up curve (standard step-up pattern)

Claims (3)

A multi-stage transmission that shifts the rotational drive output from the engine in multiple stages;
A hydraulic clutch for transmitting or interrupting a driving force transmission by the multistage transmission,
A control unit for controlling the clutch pressure of the hydraulic clutch;
In the traveling transmission device for a work vehicle having a standard pressure increasing pattern for reducing the clutch pressure to a neutral pressure that does not transmit power during shifting and then increasing the pressure from the neutral pressure to the connection pressure before the pressure reduction in a specified connection time. ,
A boost adjustment dial is provided,
The adjustment value by the boost adjustment dial has a connection time adjustment area, a standard pressure increase area, and a connection pressure adjustment area according to the value,
When the adjustment value is the standard boost region, the control unit boosts the standard boost pattern,
When it is the connection time adjustment region, the voltage is boosted by a boost pattern obtained by changing the connection time of the standard boost pattern,
When it is the connection pressure adjustment region, the standard boost pattern is boosted by a boost pattern obtained by translating to the high pressure side or the low pressure side,
A traveling transmission device for a work vehicle. The oil temperature sensor for measuring the hydraulic oil temperature of the hydraulic clutch is provided, when the oil temperature is below a predetermined temperature, regardless of the adjustment value is boosted by the standard boost pattern, working according to claim 1 Vehicle travel transmission device. 3. The traveling transmission device for a work vehicle according to claim 1, wherein when the pressure increase adjustment dial is at a maximum position, the control unit shifts without performing pressure reduction.

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