JP2007100764A - Working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a working vehicle which sets at a predetermined change gear ratio by operating a hydraulic system automatically. <P>SOLUTION: The working vehicle is provided with: a running transmission which transmits power from an engine to a drive axle via a main transmission, a main clutch, and an auxiliary transmission; and the hydraulic system which cuts the main clutch, and operates the main transmission 10 and the auxiliary transmission 30 by a hydraulic actuator. In the running transmission, the main transmission and the auxiliary change gear is disposed in series, so as to obtain a multistage change gear. A change gear ratio table derived by combination of each change gear of the main transmission and the auxiliary transmission, is stored in a ROM 115. The change gear ratio of the ROM 115 is commanded from the operation of a change gear operating lever 116 to output the predetermined change gear demand by an operator's operation. The operating signal to the change gear stage of the main and auxiliary transmissions corresponding to the change gear stage is sent from a microcomputer 111 to the driver 112. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a working vehicle such as a tractor, and more particularly to a travel transmission that transmits power from an engine to a drive axle via a main transmission, a main clutch, and a subtransmission, and a main transmission that disengages the main clutch. The present invention relates to a working vehicle including a hydraulic device that operates the device and the auxiliary transmission with a hydraulic actuator.

  Conventionally, in a working vehicle such as a tractor, in order to obtain a traveling speed (shift range) according to complicated work, there is a working vehicle in which the number of stages of the transmission is larger than that of a general vehicle such as a normal automobile. It is known (for example, refer to Patent Document 1).

  In the power transmission mechanism used in the working vehicle disclosed in Patent Document 1, the engine output transmitted to the transmission case via the main clutch is branched into the traveling system and the PTO system via the counter shaft.

  The traveling system includes a main transmission mechanism that performs a four-speed shift, a multi-plate transmission hydraulic clutch, a forward / reverse switching mechanism, and a high / low transmission mechanism that performs a two-speed shift with a small transmission ratio. A sub-transmission mechanism that performs two-stage shift with a transmission ratio and a super-deceleration mechanism are arranged in series, and the power shifted by each of these transmission mechanisms is transmitted to the rear wheels via the rear differential mechanism.

  At this time, the forward / reverse switching mechanism, the high / low speed change mechanism, and the sub-speed change mechanism are switched by the hydraulic device together with the on / off of the shift hydraulic clutch.

  This hydraulic device, for example, moves a switching sleeve between a high speed gear and a low speed gear included in the high / low speed change mechanism by a hydraulic actuator, and is provided in addition to forward / reverse switching.

Japanese Patent No. 3558221

  By the way, in the tractor as the working vehicle configured as described above, the order of the number of stages defined by the combination of the gears of the forward / reverse switching mechanism, the high / low speed change mechanism, and the auxiliary transmission mechanism is the gear arrangement order. Setting the gear ratio of the gear is very difficult, and there is a problem that setting the gear ratio becomes even more difficult when trying to obtain a desired gear ratio (vehicle speed).

  In view of the above circumstances, an object of the present invention is to provide a working vehicle capable of automatically operating a hydraulic device and setting a predetermined gear ratio.

  The working vehicle according to claim 1, wherein the main transmission is configured to disengage the main clutch, the traveling transmission that transmits power from the engine to the drive axle via the main transmission, the main clutch, and the auxiliary transmission. And a hydraulic vehicle that operates the auxiliary transmission with a hydraulic actuator, the traveling transmission includes the main transmission and the auxiliary transmission arranged in series to obtain a multi-stage transmission. A gear ratio table obtained by a combination of gears of the main transmission and the sub-transmission, a gear shift operating means for outputting a predetermined gear shift command by an operator, and a gear shift command based on the gear shift command. A control device for designating a gear ratio of the gear ratio table and transmitting an operation signal to the gear stage of the main transmission and the gear stage of the auxiliary transmission corresponding to the gear ratio to the hydraulic device. , With a, characterized in that.

  The working vehicle according to claim 2 is characterized in that the sub-transmission device is configured to obtain a shift of at least a fourth speed.

  According to the first aspect of the present invention, the multi-stage shift obtained by the combination of the respective shift stages of the main transmission and the sub-transmission is stored in the transmission ratio table arranged in the transmission table in the order of the transmission ratio. By selecting the gear ratio with the operating means, the hydraulic device can be automatically operated and set to a predetermined gear ratio, so that the operator can easily set a desired gear stage and perform all gear changes. It is possible to perform a traveling shift and efficient work with less shift shock by using the stage without waste.

  According to the second aspect of the present invention, the main transmission (or the sub-transmission) in a state where the sub-transmission (or the main transmission) is set to the predetermined speed when the sub-speed becomes the fourth speed or more. In gear shifting operations, it is difficult to arrange in order of all gear ratios, so it is possible to set a reasonable gear ratio in the gear ratio order by arbitrarily combining the gear stages of the main transmission and the sub-transmission. Become.

  Next, a working vehicle according to an embodiment of the present invention is applied to a tractor and will be described with reference to the drawings.

  FIG. 1 is a side view of a tractor according to an embodiment of the working vehicle of the present invention.

  As shown in FIG. 1, a tractor 1 as a work vehicle has an engine (not shown) mounted in the front portion 2 of the vehicle, and an output from the engine is disposed in a transmission case 3. It is transmitted to the drive axle 5 of the rear wheel 4 via (transmission).

  FIG. 2 is an explanatory diagram of the arrangement of the transmission arranged in the above-described mission case 3.

  In FIG. 2, reference numeral 10 denotes a main transmission that transmits power from an engine via an output gear 7 provided on the output shaft 6, and 20 is interposed between the main transmission 10 and the auxiliary transmission 30. The main clutch 40 is a forward / reverse switching device adjacent to the auxiliary transmission 30, and 50 is an ultra-low speed device that transmits power from the forward / reverse switching device to an axle gear 8 provided on the drive axle 5.

  The main transmission 10 includes a main shaft 12 provided with a transmission gear 11 that meshes with the output gear 7 closer to the tip, and a transmission shaft 13 that is arranged in parallel with the main shaft 12 in the front-rear direction.

  The main shaft 12 is provided with four main transmission driving gears 12a, 12b, 12c, and 12d having different conduction ratios. The gears 12a, 12b, 12c, and 12d may be separate from the main shaft 12 (for example, the gears 12a, 12b, and 12c) or may be integrated with the main shaft 12 (for example, the gear 12d).

  The transmission shaft 13 includes main transmission driven gears 13a, 13b, 13c, and 13d that mesh with the main transmission driving gears 12a, 12b, 12c, and 12d. The transmission shaft 13 is provided with always-mesh (synchromesh) type shift members 14, 15 between the gear 13a and the gear 13b and between the gear 13c and the gear 13d.

  The shift member 14 is provided between the gear 13a and the gear 13b, and is used to select the meshing of the gear 12a, the gear 13a, and the gear 13b. The shift member 15 is provided between the gear 13c and the gear 13d, and is used for selecting the meshing between the gear 13c and the gear 13d.

  Thereby, for example, when the gear 12a and the gear 13a are engaged with each other by the shift member 14 (interlocked state), the engagement between the gear 12b and the gear 13b (interlocked state) is released. At the same time, the shift member 15 is in a neutral state, and the engagement (interlocking state) between the gear 12c and the gear 13c and the gear 12d and the gear 13d is also released.

  The main clutch 20 is provided between the rear end of the transmission shaft 13 of the main transmission 10 and the front end of the auxiliary transmission shaft 31 of the auxiliary transmission 30 and constitutes, for example, a hydraulic clutch. As a result, the oil is supplied so that the driving force of the transmission shaft 13 is transmitted to the auxiliary transmission shaft 31. Further, the oil drain is turned off so that the driving force of the transmission shaft 13 is not transmitted to the auxiliary transmission shaft 31.

  The subtransmission device 30 includes a subtransmission shaft 31 and a transmission shaft 32 arranged in parallel in the front-rear direction.

  The auxiliary transmission shaft 31 is arranged coaxially with the transmission shaft 13 on the main transmission side, and is provided with four main transmission drive side gears 31a, 31b, 31c, 31d having different conduction ratios. Further, the sub-transmission shaft 31 is provided with synchromesh type shift members 33 and 34 between the gear 31a and the gear 31b and between the gear 31c and the gear 31d.

  The transmission shaft 32 is arranged coaxially with the main shaft 12 on the main transmission side, and includes sub-shift driven gears 32a, 32b, 32c, and 32d that mesh with the gears 31a, 31b, 31c, and 31d on the main transmission driving side. Yes. A reverse transmission gear 35 is provided near the tip of the transmission shaft 32.

  The shift member 33 is provided between the gear 31a and the gear 31b, and is used for selecting the meshing between the gear 31a and the gear 31b. The shift member 34 is provided between the gear 31c and the gear 31d, and is used to select the meshing between the gear 31c and the gear 31d.

  Thereby, for example, when the gear 31a and the gear 32a are engaged with each other by the shift member 33 (interlocked state), the engagement between the gear 31b and the gear 32b (interlocked state) is released. At the same time, the shift member 34 is in a neutral state, and the meshing (interlocking state) between the gear 31c and the gear 32c and the gear 31d and the gear 32d is also released.

  The forward / reverse switching device 40 includes a synchromesh-type shift member 46, a forward / reverse shaft 41 parallel to the transmission shaft 32 in the front-rear direction, and a reverse shaft coaxially connected to the tip of the forward / rearward shaft 41 ( A reverse gear sleeve) 42 and a reverse idle shaft 43 parallel to the reverse shaft 42 in the front-rear direction. In this embodiment, the interlocking shaft 44 is connected to the rear end of the forward / reverse shaft 41, but the interlocking shaft 44 may be integrated with the forward / backward shaft 41.

  The forward / reverse shaft 41 is provided with a forward gear sleeve 45 and a reverse gear sleeve 42a integrated with the reverse shaft 42 so as to be rotatable. Further, the forward gear sleeve 45 is provided with a forward gear 45 a that meshes with the gear 32 b of the transmission shaft 32 of the auxiliary transmission 30. Thereby, when the shift member 46 is meshed with the forward gear sleeve 45, the rotation of the transmission shaft 32 is directly transmitted to the forward / rearward shaft 41 via the gears 32b and 45a to rotate in the forward direction.

  The reverse shaft 42 is provided with a reverse gear 42b. The gear 42b may be formed integrally with the reverse shaft 42. The gear 42 b is provided on the reverse idle shaft 43 and meshes with the reverse idle gear 43 a that meshes with the transmission gear 35. As a result, when the shift member 46 is engaged with the reverse gear sleeve 42a, the rotation of the transmission shaft 32 is transmitted to the forward / reverse shaft 41 via the gears 35, 43a, 42b and rotates in the reverse direction.

  The interlocking shaft 44 is provided with two gears 44a and 44b.

  The ultra-low speed device 50 includes a switching shaft 51 and a final shaft 52 that are adjacent to the interlocking shaft 44 and are parallel to the front-rear direction.

  The switching shaft 51 is provided coaxially with the transmission shaft 32, and is interposed between the gear 51a meshing with the gear 44a, the ultra-low speed gear unit 53 meshing with the gear 44b, and the gear 51a and the gear unit 53. The shift member 54 and the transmission gear 55 are provided.

  The final shaft 52 includes a gear 52 a that meshes with the transmission gear 55, an ultra-low speed gear 53 b that meshes with the gear unit 53, and a differential gear 56 that meshes with the axle gear 8 provided on the drive axle 5.

  The shift member 54 is provided between the gear 51 a and the gear unit 53 and is used for selecting the meshing between the gear 51 a and the gear unit 53.

  Thereby, for example, when the gear 44a and the gear 51a are engaged with each other by the shift member 54 (interlocking state), the engagement (interlocking state) between the gear 44b and the gear unit 53 is released.

  When the gear 44a and the gear 51a are engaged with each other by the shift member 54 (interlocking state), the power of the interlocking shaft 44 passes through the gear 44a, the gear 51a, the gear 55, the gear 52a, and the differential gear 56. It is transmitted to the axle gear 8.

  On the other hand, when the gear 44b and the gear unit 53 are engaged with each other by the shift member 54 (interlocking state), the power of the interlocking shaft 44 is the gear 44b, the gear 53b of the gear unit 53, and the ultra-low speed gear 52b. Are transmitted to the axle gear 8 through the gear 53a, the gear 55, the gear 52a, and the differential gear 56.

  FIG. 3 is a hydraulic circuit diagram showing an example of hydraulic control of the main transmission 10, the main clutch 20, and the auxiliary transmission 30.

  In FIG. 3, 61 is a check valve, 62 is an oil temperature sensor, 63 is a filter, 64 is a proportional pressure control solenoid valve, 65 is a filter, 66 is a hydraulic sensor, 67 is a filter, 68 is a shuttle valve, and 69 is a relay check. It is a valve.

  The check valve 61 prevents back flow of oil supplied from an oil supply source (not shown).

  The oil temperature sensor 62 detects the temperature of the supplied oil, and the oil pressure sensor 66 detects the pressure of the supplied oil. These detection results are output to a control circuit (not shown), and the oil temperature, hydraulic pressure, and the like are controlled.

  Since the main clutch 20 needs to be in a disengaged state during a shift operation, which will be described later, the proportional pressure control solenoid valve 64 is turned off by a control circuit (not shown) during the shift operation. The supply of oil to the main clutch 20 via the shuttle valve 68 is stopped.

  In FIG. 3, reference numerals 71 and 72 denote solenoid valves for controlling the hydraulic actuator 73 that displaces the position of the shift member 33. The hydraulic actuator 73 is positioned at three positions by the pins 74. Reference numeral 75 denotes a check valve for the pin 74.

  Here, when oil is supplied from the control solenoid valve 71 to the hydraulic actuator 73, the hydraulic actuator 73 expands, and when oil is supplied from the control solenoid valve 72 to the hydraulic actuator 73, the hydraulic actuator 73 contracts. Thus, for example, when the hydraulic actuator 73 is in the extended position, the shift member 33 meshes with the gear 31b and the gear 32b, and when the hydraulic actuator 73 is in the contracted position, the shift member 33 meshes with the gear 31a and the gear 32a. When the hydraulic actuator 73 is in the intermediate position, the shift member 33 is in the neutral state.

  In FIG. 3, reference numerals 81 and 82 denote solenoid valves for controlling the hydraulic actuator 83 that displaces the position of the shift member 34. The hydraulic actuator 83 is positioned at three positions by the pins 84. Reference numeral 85 denotes a check valve for the pin 84.

  Here, when oil is supplied from the control solenoid valve 81 to the hydraulic actuator 83, the hydraulic actuator 83 expands, and when oil is supplied from the control solenoid valve 82 to the hydraulic actuator 83, the hydraulic actuator 83 contracts. Thus, for example, when the hydraulic actuator 83 is in the extended position, the shift member 34 meshes with the gear 31d and the gear 32d, and when the hydraulic actuator 83 is in the contracted position, the shift member 34 meshes with the gear 31c and the gear 32c. When the hydraulic actuator 83 is in the intermediate position, the shift member 34 is in the neutral state.

  In FIG. 3, reference numerals 91 and 92 denote solenoid valves for controlling the hydraulic actuator 93 that displaces the position of the shift member 14. The expansion / contraction position of the hydraulic actuator 93 is positioned by a pin 94. Reference numeral 95 denotes a check valve for the pin 94.

  Here, when oil is supplied from the control solenoid valve 91 to the hydraulic actuator 93, the hydraulic actuator 93 expands, and when oil is supplied from the control solenoid valve 92 to the hydraulic actuator 93, the hydraulic actuator 93 contracts. Thus, for example, when the hydraulic actuator 93 is in the extended position, the shift member 14 meshes with the gear 12b and the gear 13b, and when the hydraulic actuator 93 is in the contracted position, the shift member 14 meshes with the gear 12a and the gear 13a. When the hydraulic actuator 93 is in the intermediate position, the shift member 14 is in the neutral state.

  Further, in FIG. 3, reference numerals 101 and 102 denote solenoid valves for controlling the hydraulic actuator 103 that displaces the position of the shift member 15. The hydraulic actuator 103 is positioned at three positions by the pins 104. Reference numeral 105 denotes a check valve for the pin 104.

  Here, when oil is supplied from the control solenoid valve 101 to the hydraulic actuator 103, the hydraulic actuator 103 expands, and when oil is supplied from the control solenoid valve 102 to the hydraulic actuator 103, the hydraulic actuator 103 contracts. Thus, for example, when the hydraulic actuator 103 is in the extended position, the shift member 15 meshes with the gear 12d and the gear 13d, and when the hydraulic actuator 103 is in the contracted position, the shift member 15 meshes with the gear 12c and the gear 13c. When the hydraulic actuator 103 is in the intermediate position, the shift member 15 is in the neutral state.

  FIG. 4 is a block diagram of the hydraulic control circuit of the tractor 1 according to the present embodiment.

  As shown in FIG. 4, the shuttle valve 68 and the control solenoid valves 71, 71, 81, 82, 91, 92, 101, 102 are provided on the output side of the microcomputer unit 111 having the microcomputer 110 which is a hydraulic operation control means. Connection is made via a driver 112.

  On the input side of the microcomputer unit 110, a shift-up switch 113 and a shift-down switch 114 for detecting a shift-up and shift-down instruction at the time of shifting are connected. An oil temperature sensor 62 and a hydraulic pressure sensor 63 are connected to the input side of the microcomputer unit 110.

  On the other hand, the ROM 115 of the microcomputer unit 110 stores a speed ratio table for calling up the speed ratio based on a predetermined speed command designated by a speed change lever (speed change operation means) 116 operated by an operator.

  Thus, when the operator outputs a predetermined gear shift command by the gear shift operation lever 116, the gear ratio of the gear ratio table is designated based on the gear shift command, and the gear stage of the main transmission corresponding to the gear ratio and An operation signal to the shift stage of the auxiliary transmission is output to the driver 112.

  FIG. 5 is a chart listing the combinations of gears when the tractor 1 according to the present embodiment is moving forward.

  As shown in FIG. 5, depending on the combination of the gears of the main transmission 10, the sub-transmission device 30, and the super-low speed device 50, the main transmission 10 has four stages, the sub-transmission 30 has four stages, and the super-low speed device 50 passes through. It is possible to realize a two-speed shift (a total of 32 speeds) depending on whether or not there is.

  FIG. 6 is a table listing the combinations of gears when the tractor 1 according to this embodiment is moving backward.

  As shown in FIG. 6, depending on the combination of the gears of the main transmission 10, the sub-transmission device 30, and the super-low speed device 50, the main transmission 10 has four stages, the sub-transmission 30 has four stages, and the super-low speed device 50 passes through. It is possible to realize a two-speed shift (a total of 32 speeds) depending on whether or not there is.

  In the charts of FIGS. 5 and 6, in the present embodiment, the engagement of the gear 12a and the gear 13a of the main transmission 10 is the first stage, and the engagement of the gear 12b and the gear 13b is the second stage. The meshing of the gear 12c and the gear 13c of the main transmission 10 is the third stage, and the meshing of the gear 12d and the gear 13d is the fourth stage.

  Further, the gear 31d and the gear 32d of the auxiliary transmission 30 are engaged in the first stage, the gear 31c and the gear 32c are engaged in the second stage, and the gear 31b and the gear 32b of the main transmission 10 are engaged. The third stage, the meshing of the gear 31a and the gear 32a is the fourth stage.

  FIG. 7 is a chart of an example of the speed by the combination of each gear when the tractor 1 according to the present embodiment moves forward and backward.

  As shown in FIG. 7, the tractor 1 can be driven at a speed corresponding to the number of stages defined by the combination of gears shown in FIGS. 5 and 6, and can be run at a speed more suitable for work. It becomes.

  8 to 10 show another embodiment of the working vehicle of the present invention, in which the auxiliary transmission device 30 shown in the above embodiment has three stages.

  FIG. 8 is an explanatory view of the arrangement of the transmission arranged in the above-described mission case 3.

  In FIG. 8, 10 is a main transmission, 20 is a main clutch, 30 is a subtransmission, 40 is a forward / reverse switching device, and 50 is an ultra-low speed device. The main transmission 10, the main clutch 20, and the ultra-low speed device 50 are the same as those in the above embodiment, and the same components as those in the above embodiment are denoted by the same reference numerals and the description thereof is omitted.

  The subtransmission device 30 includes a subtransmission shaft 31 and a transmission shaft 32 arranged in parallel in the front-rear direction.

  The auxiliary transmission shaft 31 is arranged coaxially with the transmission shaft 13 on the main transmission side, and is provided with three main transmission drive side gears 31a, 31c, 31d having different conduction ratios. Further, the auxiliary transmission shaft 31 is provided with a synchromesh type shift member 33 adjacent to the gear 31a, and a synchromesh type shift member 34 is interposed between the gear 31c and the gear 31d.

  The transmission shaft 32 is arranged coaxially with the main shaft 12 on the main transmission side, and includes sub-shift driven gears 32a, 32c, and 32d that mesh with the gears 31a, 31c, and 31d on the main transmission driving side. A gear 32e is provided between the gear 32c and the gear 32d. Further, a reverse transmission gear 35 is provided near the tip of the conduction shaft 32.

  The shift member 33 is used to turn on and off the meshing between the gear 31a and the gear 32a. The shift member 34 is provided between the gear 31c and the gear 31d, and is used to select the engagement between the gear 31c and the gear 32c and the engagement between the gear 31d and the gear 32d.

  Thereby, for example, when the gear 31a and the gear 32a are engaged with each other by the shift member 33 (interlocked state), the shift member 34 is in the neutral state, and the gear 31c and the gear 32c, and the gear 31d and the gear 32d. The engagement (interlocking state) with is released.

  A multi-stage gear 41 a is provided on the forward-reverse shaft 41 of the forward-reverse switching device 40. The multi-stage gear 41a meshes with the gear 32d of the subtransmission device 30 and meshes with the gear 32e of the subtransmission device 30, and decelerates the input from the gear 32d to conduct reduced rotation to the transmission shaft 32.

  In this embodiment, when the hydraulic actuator 73 shown in FIG. 3 is supplied with oil from the control solenoid valve 71 and the hydraulic actuator 73 expands, the shift member 33 includes the gear 31a and the gear 32a. Release the mesh (neutral state).

  FIG. 9 is a chart listing the combinations of gears when the tractor 1 according to this embodiment is moving forward and backward.

  As shown in FIG. 9, depending on the combination of the gears of the main transmission 10, the sub-transmission device 30, and the super-low speed device 50, the main transmission 10 has four stages, the sub-transmission 30 has three stages, and the super-low speed device 50 passes through. A total of 22 gear shifts can be realized by combining two gear shifts depending on whether or not there is.

  FIG. 10 is a chart of an example of speed (speed ratio reference) based on a combination of gears when the tractor 1 according to the present embodiment moves forward and backward.

  As shown in FIG. 10, the tractor 1 can travel at a speed corresponding to the number of stages defined by the combination of gears shown in FIG. 9, and can travel at a speed more suitable for work.

  As described above, in the tractor 1 as the working vehicle according to the embodiment of the present invention, the multi-stage shift obtained by the combination of the respective shift stages of the main transmission 10 and the auxiliary transmission 30 is converted into the ROM 115 as the shift table. Are stored as a gear ratio table arranged in order of gear ratios, and can be automatically set to a predetermined gear ratio by the operator selecting a gear ratio with the gear shift operation lever 116, so that the operator can easily set a desired gear ratio. The speed can be set, and all the speeds can be used without waste, and the traveling speed change and the efficient work with less speed change shock can be performed.

  By the way, in the said embodiment, although the example applied to the tractor 1 as a working vehicle was disclosed, it is needless to say that it is applicable to other agricultural working machines, a construction vehicle, etc.

It is a side view of the tractor concerning one embodiment of the working vehicle of the present invention. It is arrangement | positioning explanatory drawing of the transmission arrange | positioned in the mission case which concerns on one Embodiment of the working vehicle of this invention. FIG. 3 is a hydraulic circuit diagram illustrating hydraulic control examples of a main transmission, a main clutch, and an auxiliary transmission according to an embodiment of the working vehicle of the present invention. 1 is a block diagram of a hydraulic control circuit according to an embodiment of a working vehicle of the present invention. It is the table | surface which listed the combination of each gear at the time of advance of the tractor which concerns on one Embodiment of the working vehicle of this invention. It is the chart which listed the combination of each gear at the time of reverse drive of the tractor which concerns on one Embodiment of the working vehicle of this invention. It is a chart of an example of the speed by the combination of each gear at the time of forward / backward traveling of the working vehicle according to the present embodiment. It is arrangement | positioning explanatory drawing of the transmission arrange | positioned in the mission case which concerns on other embodiment of the working vehicle of this invention. It is the table | surface which listed the combination of each gear at the time of the forward / backward travel of the tractor which concerns on other embodiment of the working vehicle of this invention. It is a table | surface of an example of the speed (speed ratio reference | standard) by the combination of each gear at the time of the forward / backward advance of the working vehicle concerning other embodiment of the working vehicle of this invention.

Explanation of symbols

1 Tractor (work vehicle)
DESCRIPTION OF SYMBOLS 5 Drive axle 10 Main transmission 20 Main clutch 30 Sub transmission 73 Hydraulic actuator 83 Hydraulic actuator 93 Hydraulic actuator 103 Hydraulic actuator 112 Driver (hydraulic device)
111 Microcomputer (control device)
115 ROM (speed ratio table)
116 Shift operation lever (shift operation means)

Claims (2)

A travel transmission that transmits power from the engine to the drive axle via a main transmission, a main clutch, and a sub-transmission; and
In a working vehicle comprising: a hydraulic device that disengages the main clutch and operates the main transmission and the sub-transmission with a hydraulic actuator;
The travel transmission is configured such that a multi-stage shift can be obtained by arranging the main transmission and the auxiliary transmission in series.
A gear ratio table obtained by a combination of gears of the main transmission and the sub-transmission,
Shift operation means for outputting a predetermined shift command by an operator operation;
A control device for designating a gear ratio of the gear ratio table based on the gear ratio command and transmitting an operation signal to the gear position of the main transmission and the gear position of the auxiliary transmission corresponding to the gear ratio to the hydraulic device; With
A working vehicle characterized by that. The sub-transmission device is configured to obtain a shift of at least four speeds.
The working vehicle according to claim 1.

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