Speed data display system for a work vehicle

A speed change display control device includes a display screen generator generating a first display screen and a second display screen. The first display screen includes: an auxiliary speed change stage display area displaying auxiliary speed change stages; a main speed change stage display area displaying main speed change stages assigned to the auxiliary speed change stages; and an engaged speed change stage display area displaying engaged speed change stages. The second display screen includes: the auxiliary speed change stage display area; the main speed change stage display area; a lower limit selection area where the speed change stage defining a lower limit of a vehicle speed change ratio is selected; an upper limit selection area where the speed change stage defining an upper limit of the vehicle speed change ratio is selected; and a selected speed change stage display area displaying the currently selected upper limit and lower limit speed change stages.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. §119 of Japanese Application No. 2014-157701, filed on Aug. 1, 2014, the disclosure of which is expressly incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a speed change display control device for a traveling work vehicle that includes: a main speed change device switching between speed change stages without interrupting transmission of drive power; an auxiliary speed change device switches between speed change stages accompanied by an interruption in the transmission of drive power; and a speed change controller outputting a speed change control command to the main speed change device and the auxiliary speed change device and creating a vehicle speed change ratio with combinations of main speed change stages of the main speed change device and auxiliary speed change stages of the auxiliary speed change device.

2. Description of Related Art

In order to achieve various speeds (vehicle speeds) appropriate to work travel and road travel in a traveling work vehicle such as a tractor, a speed change controller is commonly used which combines a main speed change device and an auxiliary speed change device to create a vehicle speed change ratio of twenty or more speeds.

For example, Japanese Patent Laid-open Publication No. 2008-57674 discloses a work vehicle that includes a main speed change device having eight speed change stages and an auxiliary speed change device having three speed change stages. The speed change stage of the main speed change device is determined by a main speed change lever, which can be operated to speed change positions for speed 1 to speed 8. The speed change stage of the auxiliary speed change device is determined by an auxiliary speed change lever, which can be operated to three speed change positions. The operation positions of the main speed change lever are displayed on a display having seven segments. Therefore, a driver can set a desired speed change stage from among the eight speed change stages while looking at the display.

An agricultural tractor disclosed by Japanese Patent Laid-open Publication No. 2009-214877 includes a main speed change device, which achieves eight speed change stages through combination of a four-stage first main speed change device and a two-stage second main speed change device; and an auxiliary speed change device, which is capable of three speed change stages. Because a main clutch switching operation is required when operating the auxiliary speed change device, a main clutch pedal is depressed and an operation lever is operated in a front/back direction or a left/right direction, and the main clutch pedal is released after the speed change operation. In addition, with respect to the main speed change device, speed is changed by pressing down an acceleration switch and a deceleration switch provided to a knob on the operation lever. Specifically, by pressing an acceleration switch37in order from speed 1, the speed is changed one stage at a time, up to speed 8. When the main speed change device is instead in the speed 8 position, by pressing the deceleration switch in order, the speed can be reduced from speed 8 to speed 1. A display of the selected speed change stage is given via a liquid crystal display provided to an instrument panel. The speed change position of the auxiliary speed change device is displayed in a top left area of the liquid crystal display, and the speed change position of the main speed change device is displayed in reverse on a right side of the liquid crystal display.

In traveling work vehicles such as those described above, a plurality of speed change stages are obtained through the combination of a main speed change device and an auxiliary speed change device. However, employing the correct speed change stages in a simple manner in order to achieve smooth work travel has not yet been achieved. In view of this, the present invention provides a speed change display control device capable of correctly employing a plurality of speed change stages obtained by combining a main speed change device and an auxiliary speed change device.

SUMMARY OF THE INVENTION

One aspect of the present invention is a speed change display control device for a traveling work vehicle that includes: a main speed change device switching between speed change stages without interrupting transmission of drive power; an auxiliary speed change device switching between speed change stages accompanied by an interruption in the transmission of drive power; and a speed change controller outputting a speed change control command to the main speed change device and the auxiliary speed change device and creating a vehicle speed change ratio with combinations of main speed change stages of the main speed change device and auxiliary speed change stages of the auxiliary speed change device. The speed change display control device includes a display screen generator generating a first display screen and a second display screen. The first display screen includes an auxiliary speed change stage display area displaying a grouping of the auxiliary speed change stages; a main speed change stage display area displaying a grouping of the main speed change stages assigned to the auxiliary speed change stages; and an engaged speed change stage display area displaying the engaged speed change stages, which are obtained through the combination of the main speed change stage currently in use and the auxiliary speed change stage currently in use. The second display screen includes the auxiliary speed change stage display area; the main speed change stage display area; a lower limit selection area where the speed change stage defining a lower limit of the vehicle speed change ratio is selected; an upper limit selection area where the speed change stage defining an upper limit of the vehicle speed change ratio is selected; and a selected speed change stage display area displaying the currently selected upper limit and lower limit speed change stages.

According to this configuration, the first display screen, which a driver focuses on while traveling, is provided with the auxiliary speed change stage display area displaying the grouping of auxiliary speed change stages and the main speed change stage display area displaying the grouping of main speed change stages assigned to the auxiliary speed change stages, and is further provided with the engaged speed change stage display area displaying the main speed change stage currently in use and the auxiliary speed change stage currently in use. Accordingly, the driver can easily view the speed change stage currently in use while looking at the plurality of main speed change stages and the plurality of auxiliary speed change stages. Thus, the driver can readily recognize how far the position occupied by the speed change stage currently in use is from the minimum speed stage and the maximum speed stage, and can understand the appropriate speed change stage to select next. Moreover, in the speed change device to which the present invention is applied, a speed change range that can be achieved by the speed change operation can be selected from a group of a plurality of speed change stages (vehicle speed change ratio) obtained by combining the main speed change stages of the main speed change device and the auxiliary speed change stages of the auxiliary speed change device, and that selection can be made via the second display screen. In other words, the speed change stage defining the lower limit of the vehicle speed change ratio can be selected in the lower limit selection area, and the speed change stage defining the upper limit of the vehicle speed change ratio can be selected in the upper limit selection area. The auxiliary speed change stage display area and the main speed change stage display area of the second display screen are shared with the first display screen; therefore, the driver can readily become familiar with the display.

In another aspect of the present invention, the auxiliary speed change stage display area and the main speed change stage display area each have a semicircular bar graph shape. Accordingly, the auxiliary speed change stage display area and the main speed change stage display area do not spread laterally and are displayed with focus placed on a single point; therefore, the auxiliary speed change stage and the main speed change stage can be identified at a glance.

In another aspect of the present invention, the lower limit selection area and the upper limit selection area each have a semicircular bar graph shape coaxial with the semicircles formed by the auxiliary speed change stage display area and the main speed change stage display area. With this configuration, the auxiliary speed change stage display area and the main speed change stage display area are displayed with focus placed on a shared single point; therefore, the driver can identify both the auxiliary speed change stage and the main speed change stage at a glance. When the number of main speed change stages is less than the number of auxiliary speed change stages, by positioning the main speed change stage display area on a diameter-direction exterior of the auxiliary speed change stage display area and positioning the upper limit selection area on the diameter-direction exterior of the lower limit selection area, the space required can be minimized even when all of the main speed change stages are provided above each of the auxiliary speed change stages.

In another aspect of the present invention, a lower limit setting indicator indicating the lower limit speed change stage is arranged in the lower limit selection area so as to be capable of moving within the lower limit selection area, and an upper limit setting indicator indicating the upper limit speed change stage is arranged in the upper limit selection area so as to be capable of moving within the upper limit selection area. By employing such a display layout, visual comprehension is facilitated in a task of selecting the lower limit speed change stage and the upper limit speed change stage.

Moreover, when the engaged speed change stage display area and the selected speed change stage display area share a display area, a selection range of the speed change stages can be identified much as the speed change stage during travel is identified, facilitating familiarization with a task of selecting the speed change stage.

In another aspect of the present invention, the display screen generator further generates a third display screen, the third display screen being an engaged speed change stage selection screen on which a speed change stage to be used is selected from the grouping of main speed change stages. By employing such a configuration, the task of selecting the speed change stages that can actually be used from the grouping of main speed change stages can also be performed via a display provided by the first and second display screens.

DETAILED DESCRIPTION OF THE INVENTION

Before describing specific embodiments of a traveling work vehicle according to the present invention, basic principles of speed change controls according to the present invention are described with reference toFIG. 1. The traveling work vehicle according to the present invention includes a transmission3changing a speed of drive power from an engine20and transmitting the drive power to drive wheels. The transmission3includes a main speed change device30and an auxiliary speed change device31. The main speed change device30is of a type that switches between speed change stages without interrupting the transmission of drive power, whereas the auxiliary speed change device31is of a type that switches between speed change stages accompanied by an interruption in the transmission of drive power. Hereafter, controls switching between speed change stages in the main speed change device30and the auxiliary speed change device31, i.e., so-called fundamentals of speed change control, are described with reference toFIG. 1. In the present example, the main speed change device30includes 1 to “n” speed change stages (where “n” is a natural or whole number, typically signifying a number between 4 and 8). The auxiliary speed change device31includes A to F speed change stages (reference symbols A to F are used to differentiate variable stages and do not signify the number of variable stages; typically, there are between 2 and 8 variable stages). A single vehicle speed change ratio is created through combination of the selected speed change stage of the main speed change device30and the selected speed change stage of the auxiliary speed change device31. InFIG. 1, a combination speed change stage of this kind is depicted by a combination of the numerical value (natural number) of the speed change stage of the main speed change device30and the reference symbol (alphabetic letter) of the speed change stage of the auxiliary speed change device31.

A driver operates a first operation portion MU to switch the speed change stage of the main speed change device30and operates a second operation portion SU to switch the speed change stage of the auxiliary speed change device31. The first operation portion MU and the second operation portion SU can be configured or activated by a lever, a button, a dial, or any combination of the above. Whatever the configuration, the first operation portion MU outputs an operation instruction to the main speed change device30for a speed change acceleration (upshift) or a speed change deceleration (downshift), and the second operation portion SU outputs an operation instruction to the auxiliary speed change device31for the speed change acceleration (upshift) or the speed change deceleration (downshift).

The operation instructions output from the first operation portion MU and the second operation portion SU are input to a speed change control portion6. The speed change control portion6outputs a speed change control instruction to the main speed change device30, the auxiliary speed change device31, or to both the main speed change device30and the auxiliary speed change device31, giving an instruction to create an appropriate vehicle speed change ratio based on the input operation instruction. InFIG. 1, for the purposes of description, a speed change stage switching function of the speed change control portion6is separated into a first travel controller61, which generates a speed change control instruction exclusively switching the speed change stage of the main speed change device30, and a second travel controller62, which generates a speed change control instruction that also involves switching the speed change stage of the auxiliary speed change device31.

The speed change control portion6includes a work travel mode employed when traveling while the traveling work vehicle performs work in a work field; and a road travel mode employed when the traveling work vehicle travels at a comparatively high speed on a road, such as a public road. The controls switching between speed change stages in the speed change control portion6can be defined so as to be different in the two travel modes. The controls switching between speed change stages in the work travel mode are shown in the schematic diagram ofFIG. 1.

As can be understood fromFIG. 1, when an upshift instruction is input from the first operation portion MU, the speed change stage of the main speed change device30is raised one stage and the speed change stage of the auxiliary speed change device31is maintained. When the speed change stage of the main speed change device30prior to such an operation is already the maximum speed stage (stage “n” inFIG. 1), the speed change stage of the main speed change device30and the speed change stage of the auxiliary speed change device31are maintained and the overall vehicle speed change ratio does not change. Specifically, an upshift changing the speed change stage of the auxiliary speed change device31is not performed in response to the upshift instruction from the first operation portion MU. Similarly, when a downshift instruction is input from the first operation portion MU, the speed change stage of the main speed change device30is lowered one stage and the speed change stage of the auxiliary speed change device31is maintained. When the speed change stage of the main speed change device30prior to such an operation is already the minimum speed stage (stage1inFIG. 1), the speed change stage of the main speed change device30and the speed change stage of the auxiliary speed change device31are maintained and the overall vehicle speed change ratio does not change. Specifically, a downshift changing the speed change stage of the auxiliary speed change device31is not performed in response to the downshift instruction from the first operation portion MU.

The second operation portion SU is used to switch the speed change stage of the auxiliary speed change device31. When an upshift instruction is input from the second operation portion SU, the speed change stage of the auxiliary speed change device31is raised one stage and, in principle, the speed change stage of the main speed change device30is switched to the minimum speed stage. Specifically, one speed change stage higher in the auxiliary speed change device31and stage1in the main speed change device30are combined by the upshift instruction from the second operation portion SU. This avoids causing a significant change in the vehicle speed change ratio by upshifting the auxiliary speed change device31. However, a speed change stage configuration is such that even when the auxiliary speed change device31is upshifted while the speed change stage of the main speed change device30is at the maximum speed stage, and one speed change stage higher in the auxiliary speed change device31and stage1in the main speed change device30are combined, only a slight speed change differential results. With such a configuration, in an exceptional case, one speed change stage higher in the auxiliary speed change device31may be combined with a speed change stage at least one stage higher than the minimum speed stage of the main speed change device30(stage2inFIG. 1) (shown inFIG. 1by a dotted line moving from Bn to C2). In addition, when the speed change stage of the auxiliary speed change device31is already at the maximum speed stage, the upshift instruction is ignored.

Similarly, when a downshift instruction is input from the second operation portion SU, the speed change stage of the auxiliary speed change device31is lowered one stage and, in principle, the speed change stage of the main speed change device30is switched to the maximum speed stage. Specifically, one speed change stage lower in the auxiliary speed change device31and the maximum speed stage in the main speed change device30are combined by the downshift instruction from the second operation portion SU. This avoids causing a significant change in the vehicle speed change ratio by downshifting the auxiliary speed change device31. However, a speed change stage configuration is such that even when the auxiliary speed change device31is downshifted while the speed change stage of the main speed change device30is at the minimum speed stage, and one speed change stage lower in the auxiliary speed change device31and the maximum speed stage in the main speed change device30are combined, only a slight speed change differential results. With such a configuration, in an exceptional case, one speed change stage lower in the auxiliary speed change device31is combined with a speed change stage at least one stage lower than the maximum speed stage of the main speed change device30(shown inFIG. 1by a dotted line moving from C1to Bn−1). In addition, when the speed change stage of the auxiliary speed change device31is already at the minimum speed stage, the downshift instruction is ignored.

During road travel, a travel load is light and the traveling work vehicle benefits from its own inertia; therefore, there is a low potential that a shock will occur due to a momentary interruption in transmission of drive power caused when switching the speed change stage of the auxiliary speed change device31. Therefore, in the road travel mode defined during road travel, in an exceptional case, a configuration is also possible that involves switching the speed change stage of the auxiliary speed change device31in response to the speed change operation instruction from the first operation portion MU. Although not shown inFIG. 1, when the upshift instruction is output from the first operation portion MU while the main speed change device30is at the maximum stage, for example, the speed change stage of the auxiliary speed change device31switches to one speed change stage higher, and the main speed change device30also switches to the minimum speed stage (stage1) or to a speed change stage at least one stage higher than the minimum speed stage. Similarly, when the downshift instruction is output from the first operation portion MU while the main speed change device30is at the maximum speed stage (stage n), the speed change stage of the auxiliary speed change device31switches to one speed change stage lower, and the main speed change device30also switches to the maximum speed stage (stage n) or to a speed change stage at least one stage lower than the maximum speed stage (stage n−1).

In a case where the speed change stages obtained by combining the main speed change device30and the auxiliary speed change device31exceed twenty, the speed change stages are almost never all used in normal work travel or road travel. Enabling only the speed change stages that are conceivably required for work travel or road travel to be performed soon thereafter is preferred. With reference toFIG. 2, a preferred embodiment is described in which only the speed change stages occupying a desired speed change range are selected from all of the speed change stages created by the combination of the main speed change device30and the auxiliary speed change device31. In order to facilitate the description, in the present example, the main speed change device30includes four speed change stages numbered 1 to 4, and the auxiliary speed change device31includes six speed change stages designated A to F.

A display screen displayed using a display screen generator81on a display device, such as a liquid crystal panel installed in the traveling work vehicle, performs a critical role in speed change stage selection. The display screen includes a first display screen101and a second display screen200. As shown inFIG. 2, the first display screen101is one target notification screen notifying the driver of various information during travel. Arranged in the first display screen101are an engine revolutions display area, a stored engine revolutions display area, a drive direction (forward or reverse) display area, and the like, as well as a speed change status display area102which is arranged on a lower right side of the first display screen101and indicates the currently selected speed change stage of the main speed change device30and the currently selected speed change stage of the auxiliary speed change device31.

The speed change status display area102of the first display screen101includes an auxiliary speed change stage display area202displaying a grouping of speed change stages of the auxiliary speed change device31; a main speed change stage display area201displaying a grouping of speed change stages of the main speed change device30assigned to each speed change stage of the auxiliary speed change device31; and an engaged speed change stage display area103displaying the engaged speed change stages, which integrate the speed change stage of the main speed change device30currently in use and the speed change stage of the auxiliary speed change device31currently in use to determine the vehicle speed change ratio. The second display screen200is used as a speed change stage selection screen, and therefore when generated is modeled on the speed change status display area102of the first display screen101. In addition, the second display screen200is able to transition from the first display screen101through a predetermined operation. The auxiliary speed change stage display area202and the main speed change stage display area201are arranged on the second display screen200, as well as, instead of the engaged speed change stage display area103, a selected speed change stage display area203displaying the speed change stage selected in a speed change stage selection task. Moreover, a lower limit selection area204and an upper limit selection area205are additionally arranged on the second display screen200. In the lower limit selection area204, the combined speed change stages of the main speed change device30and the auxiliary speed change device31that define a lower limit on the vehicle speed change ratio are selected, whereas in the upper limit selection area205, the combined speed change stages of the main speed change device30and the auxiliary speed change device31that define an upper limit on the vehicle speed change ratio are selected.

In the example shown inFIG. 2, the auxiliary speed change stage display area202and the main speed change stage display area201are configured by a semicircular bar graph centered on substantially a middle of the selected speed change stage display area203. Accordingly, the combined speed change stages of the main speed change device30and the auxiliary speed change device31can be specified via a line extending in a diameter direction that passes through a center of the semicircle. Moreover, the lower limit selection area204and the upper limit selection area205are each also configured by a semicircular bar graph centered on the same point. In other words, the auxiliary speed change stage display area202, the main speed change stage display area201, the lower limit selection area204, and the upper limit selection area205are arranged so as to be coaxial. The components may be arranged in any diameter direction order; however, in the example shown inFIG. 2, the components are arranged in the order of, outward in the diameter direction, the auxiliary speed change stage display area202, the main speed change stage display area201, the lower limit selection area204, and the upper limit selection area205.

A lower limit setting indicator206indicating the lower limit speed change stage is arranged in the lower limit selection area204so as to be capable of moving within the lower limit selection area204. An upper limit setting indicator207indicating the upper limit speed change stage is arranged in the upper limit selection area205so as to be capable of moving within the upper limit selection area205. In the present example, a plus button206aand a minus button206bdisplacing (or used to move or set) the lower limit setting indicator206and a plus button207aand a minus button207bdisplacing (or used to move or set) the upper limit setting indicator207are provided as software buttons, e.g., touchscreen buttons. Instead of such software buttons, a configuration may also be employed in which the lower limit setting indicator206and the upper limit setting indicator207are moved directly by dragging, or alternatively hardware buttons may be provided. In any of these cases, the lower limit setting indicator206and the combined speed change stage of the main speed change device30and the auxiliary speed change device31can be positioned on a line extending in the diameter direction through the center of the semicircle and can be displayed on a left side of the selected speed change stage display area203as the lower limit speed change stage. In addition, the upper limit setting indicator207and the combined speed change stage of the main speed change device30and the auxiliary speed change device31can be positioned on a line extending in the diameter direction through the center of the semicircle can be displayed on a right side of the selected speed change stage display area203as the upper limit speed change stage.

Accordingly, the combined speed change stage of the main speed change device30and the auxiliary speed change device31achieved by operating the first operation portion MU or the second operation portion SU can be limited to a speed change range selected through the above-described speed change stage selection process.

Moreover, the main speed change device30can also be configured to be capable of selecting the engaged speed change stages. The speed change stage selection process of the main speed change device30can, for example, be performed via an engaged speed change stage selection screen300for the main speed change device30, as shown inFIG. 3, which is an exemplary third display screen300. In order to facilitate description, the main speed change device30includes four speed change stages numbered 1 to 4 in the present example, as well. Four horizontal bars301representing the four speed change stages are arranged on the left side of the engaged speed change stage selection screen300, and a selected speed change stage and non-selected speed change stages can be differentiated by an image color or image pattern of the horizontal bars301. A selected speed change stage display field302is arranged below the four horizontal bars301, showing the selected speed change stages as a numerical value (for example, “2-4”). A lower limit setting indicator303indicating the lower limit speed change stage and an upper limit setting indicator304indicating the upper limit speed change stage are arranged in a line on a right side of the engaged speed change stage selection screen300. In the present example, a plus button303aand a minus button303bdisplacing (or can be used to move or set) the lower limit setting indicator303and a plus button304aand a minus button304bdisplacing (or can be used to move or set) the upper limit setting indicator304are provided as software buttons. Instead of such software buttons, a configuration may also be employed in which the lower limit setting indicator303and the upper limit setting indicator304are moved directly by dragging, or hardware buttons may be provided.

The above-noted selection of the engaged speed change stages can be set independently for the work travel mode and the road travel mode. In a case where a narrow speed change range is used in the work travel mode and a broad speed change range is used in the road travel mode, a configuration is preferred in which selection of the speed change range of the main speed change device30using the third display screen300is enabled during the work travel mode and selection of the speed change stage of the main speed change device30and the auxiliary speed change device31using the second display screen200is enabled during the road travel mode.

Next, a specific embodiment of the traveling work vehicle according to the present invention is described with reference to the drawings.FIG. 4is a side view of a tractor exemplary of the traveling work vehicle. As illustrated inFIG. 4, in the tractor, an engine20is mounted on a front portion of a vehicle body1of the tractor and a transmission3is mounted rearward of the engine20, the vehicle body1being supported by front wheels2aand rear wheels2b. Rearward of the vehicle body1, a rotary tilling apparatus is provided as an exemplary work apparatus22so as to be vertically movable via a link mechanism23. The tractor is a four-wheel-drive vehicle and drive power of the engine20is transmitted, via a speed change mechanism installed in the transmission3, to the rear wheels2band front wheels2a, which are capable of acting as drive wheels. Moreover, the drive power of the engine20is also transmitted to the work apparatus22via a PTO shaft24, which projects rearward from the transmission3. The engine20is covered by a hood21. A cabin10is supported on the vehicle body1to the rear of the hood21and above the transmission3.

Although only depicted schematically inFIG. 5, the transmission3of the present embodiment includes the main speed change device30and the auxiliary speed change device31as the speed change mechanism, and the main speed change device30further incorporates a forward/reverse travel switching mechanism32. Speed-changed drive power from the transmission3is transmitted to the rear wheels2bvia a differential mechanism33and a rear wheel axle34. Although not depicted in detail, the speed-changed drive power from the transmission3can also be transmitted to the front wheels2a. The main speed change device30is of a type that switches between four speed change stages using a constant mesh gear set and a plurality of clutches, without interrupting the transmission of drive power. The auxiliary speed change device31is of a type switching between six speed change stages accompanied by an interruption in the transmission of drive power (referred to as a synchromesh type).

Referring back toFIG. 4, an interior of the cabin10serves as a driver space, at a front portion of which is arranged a steering wheel or handle11steering the front wheels2aand at a rear portion of which is arranged a driver seat12, with the driver seat12being positioned between a left-right pair of rear wheel fenders15. An armrest operation device4, having a multifunction operation tool5, is provided spanning from a side of the driver seat12to a front side thereof. A display13which visually notifies the driver of various information is provided on a front side of the armrest operation device4.

As shown inFIGS. 6 and 7, the armrest operation device4includes an armrest support base4A which is fixed to a mounting bracket4B, with the mounting bracket4B being fixed to a support frame not shown in the drawings. A support rod or member4C, which inclines upward while extending forward, is fixed to the mounting bracket4B, and the display13(such as a liquid crystal panel and the like) is mounted on a forefront end of the support rod4C. The display13allows an input operation to be performed via a touchscreen panel13A and can also accept various operation inputs by the driver.

As is apparent fromFIG. 6, the armrest operation device4can be divided into a front region4a, a middle region4b, and a rear region4cin a plan view. A cushioning armrest bed40, on which an arm can be rested, is located in the rear region4c. The multifunction operation tool5, described in detail hereafter, is provided to substantially a left half of the front region4a. A first operation switch group9aand a second operation switch group9bare provided as operation switch groups9to substantially a right half of the front region4a. From the left, a third operation switch group9c, a fourth operation switch group9d, and a fifth operation switch group9eare arranged as operation switch groups9disposed on the middle region4b. The operation switches provided to each of the operation switch groups9may have various forms such as a button, switch, dial, lever, joystick, or the like types.

The multifunction operation tool5is arranged in a front end area on the left side of the armrest base40and is supported so as to be capable of pivoting about a pivot axis P1. The multifunction operation tool5is used to control a travel status of the tractor and a status of the work apparatus22mounted on the tractor. The multifunction operation tool5is substantially configured by a grip main body5A and a pivoting body5B. As can be seen inFIG. 8, the pivoting body5B is formed as an arm member that pivots about the pivot axis P1. The vehicle is configured to accelerate by swinging the pivoting body5B in a forward direction (up) from a pivot-neutral position of the pivoting body5B, and to decelerate by swinging the pivoting body5B in a backward direction (down) from the pivot-neutral position.

The grip main body5A is provided on a free end side of the pivoting body5B. As illustrated inFIG. 8, the grip body5A is configured by a grip part50that is formed in a right side area, here substantially a right half area, and an extension part51(where operation switch groups9are arranged) that is formed in a left side area, here substantially a left half area. An outer peripheral surface of the grip body5A is defined by a convex surface52, a vertical lateral surface53, a back surface54a, and a bottom surface54b. The convex surface52is shaped so that a palm gripping the grip part50easily covers the convex surface52. The vertical lateral surface53is a surface which extends substantially perpendicularly with respect to a left edge of the convex surface52. A tongue piece protruding outward is formed as a hypothenar rest55on a bottom edge of the grip part50, that is, on at least a portion of a boundary area between the bottom surface54band the convex surface52. The hypothenar rest55is shaped to hold the hypothenar of a hand resting on the grip part50so that the palm does not slip downward.

A top surface of the extension part51has a surface that is substantially flat or very slightly convex. Because, in actual application, the top surface of the extension part51is arranged so as to face an operator, the top surface of the extension part51is hereafter also referred to as an operator-facing surface56. The operator-facing surface56has a shape that extends in a left direction from a bottom edge of the vertical lateral surface53of the grip part50, with the grip part50and the extension part51connected and the operator-facing surface56and the vertical lateral surface53intersecting substantially perpendicular to each other. Thus, a space defined by the operator-facing surface56and the vertical lateral surface53is large enough that the thumb of the hand resting on the grip part50can move freely to a certain extent. For this reason, this space is referred to as a thumb space TS.

Operation switches (including buttons, levers, and the like) that belong to the operation switch groups9are arranged on the vertical lateral surface53and the operator-facing surface56. In the present embodiment, a shuttle button91and a speed change ratio fixing button93that belong to a travel-related operation switch group9, and an up/down button92and two hydraulic control switches94aand94bthat belong to a work-related operation switch group9, are provided on the operator-facing surface56. The shuttle button91is arranged on substantially an upper half (front half) of the operator-facing surface56, in a position closest to the vertical lateral surface53. The up/down button92is arranged next to the shuttle button91on a left side and the speed change ratio fixing button93is arranged further left next to the shuttle button91. The hydraulic control switches94aand94bare arranged side by side on substantially a lower half (front half) of the operator-facing surface56. In addition, a speed change auxiliary button95is arranged on the vertical lateral surface53. Further, a shuttle auxiliary button96is arranged on the back surface54aof the grip part50. The shuttle auxiliary button96can be easily operated with the index finger or the middle finger of the hand whose palm is resting on the convex surface52of the grip part50.

The shuttle button91switches the forward/reverse travel switching mechanism32of the transmission3to a forward travel state when an upward arrow portion of the shuttle button91is pressed along with the shuttle auxiliary button96, and switches the forward/reverse travel switching mechanism32of the transmission3to a reverse travel state when a downward arrow portion of the shuttle button91is pressed along with the shuttle auxiliary button96. That is, the forward/reverse travel switching mechanism32can be controlled and forward travel and reverse travel of the tractor can be selected by pressing the shuttle button91with the thumb while pressing the shuttle auxiliary button96with the middle finger or the index finger.

As described above, the main speed change device30of the transmission3is of a type switching between four speed change stages without interrupting the transmission of drive power, whereas the auxiliary speed change device31is of a type switching between six speed change stages accompanied by an interruption in the transmission of drive power (referred to as a synchromesh type). To this end, when switching speed change stages (upshifting/downshifting) via the pivoting operation of the grip part50about the pivot axis P1, the operation switching the speed change stage of only the main speed change device30(not switching the auxiliary speed change device31) can be enabled even without pressing the speed change auxiliary button95. However, the speed change stage switching operation that involves switching the auxiliary speed change device31can be disabled when the speed change auxiliary button95is not pressed. Specifically, in the present embodiment, in a state where the speed change auxiliary button95is not pressed, the multifunction operation tool5can act as the first operation portion MU, whereas in a state where the speed change auxiliary button95is pressed, the multifunction operation tool5can act as the second operation portion SU.

In addition, the transmission3is configured such that an appropriate speed change ratio can be set according to a vehicle speed. However, there are cases during performance of work and the like in which it is preferable to maintain the speed change ratio even when the vehicle speed temporarily changes. In order to overcome this issue, the speed change ratio fixing button93is configured as a button that forcibly fixates the speed change ratio and, by operating the speed change ratio fixing button93, the speed change ratio of the transmission3does not change even when the vehicle speed decreases due to brake operation and the like.

The up/down button92is divided into an upper button or portion and a lower button or portion. Pressing the upper button of the up/down button92causes the work apparatus22to be lifted and pressing the lower button of the up/down button92causes the work apparatus22to be lowered. The hydraulic control switches94aand94bcontrol valves of hydraulic piping connected to the work apparatus22.

FIG. 9illustrates speed change stages before and after an operation toward an acceleration side (upshift) and an operation toward a deceleration side (downshift) are performed using the multifunction operation tool5. The speed change stages of the main speed change device30are indicated by the numbers 1 to 4, and the speed change stages of the auxiliary speed change device31are indicated by the letters A to F. The post-speed change operation speed change stages are divided into speed change stages resulting from upshifting or downshifting the grip portion50without pressing the speed change auxiliary button95(main speed change stage switching operation) and speed change stages resulting from upshifting or downshifting the grip portion50while pressing the speed change auxiliary button95(auxiliary speed change stage switching operation). The speed change stages after the main speed change stage switching operation are divided by road travel and work travel. The results shown inFIG. 9correspond to the discussion ofFIG. 1, and thus a description thereof is omitted here.

All of the speed change stages 1 to 4 of the main speed change device30and all of the speed change stages A to F of the auxiliary speed change device31are represented in the summarized speed change stage switching table ofFIG. 9. However, as noted with reference toFIG. 2, a usable speed change stage range can be selected from the speed change stages created by the combination of the main speed change device30and the auxiliary speed change device31in the tractor, as well. Moreover, as noted with reference toFIG. 3, a usable speed change stage range can also be selected from the speed change stages of the main speed change device30.

InFIG. 10, a control system equipped on the tractor is illustrated in the form of a functional block diagram. In the control system, functions achieved primarily by a computer program, e.g., installed, stored or running on computer hardware, are represented as a calculation control device800; however, this distinction is made purely for the purposes of description and the structure of an actual control system can be divided or consolidated as desired. The calculation control device800is connected to other portions by an in-vehicle LAN or the like so as to be capable of data transmission. Examples of such portions include a device controller801, an input signal processor802, a notification processor803, and the like. In addition, various functions and portions within the calculation control device800are also connected by the in-vehicle LAN or some other data transmission path so as to be capable of data transmission.

The device controller801provides operation signals to various operation devices provided to the engine20, the transmission3, the work apparatus22, and the like, controlling the operation thereof. The input signal processor802is an input interface, inputting signals from the multifunction operation tool5, the operation switch groups9, and the group of status detection sensors90that includes various sensors and transferring the input signals to various portions of the control system. The notification processor803is an input/output interface, processing image signals output to the display13, audio signals output to a speaker (not shown), or operation input signals from the touchscreen panel13A.

The calculation control device800shown inFIG. 10includes a speed change controller6, a work controller7A, a work travel support portion or controller7B, a display controller8, a travel status determiner60, and the like.

The speed change controller6outputs a speed change control command to the main speed change device30and the auxiliary speed change device31via the device controller801, and creates a vehicle speed change ratio with combinations of speed change stages of the main speed change device30and the auxiliary speed change device31. The speed change controller6includes a first travel controller61, a second travel controller62, and a speed change stage setting portion63. In the work travel mode, the first travel controller61generates the speed change control command to switch between only the speed change stages of the main speed change device30in response to a speed change operation command issued due to pivot operation of the multifunction operation tool5in a state where the speed change auxiliary button95is not pressed. As described above, in the road travel mode, there may be exceptional cases where switching between the speed change stages of the auxiliary speed change device31is also involved. The second travel controller62generates the speed change control command that involves switching between the speed change stages of the auxiliary speed change device31in response to the speed change operation command issued due to pivot operation of the multifunction operation tool5in a state where the speed change auxiliary button95is pressed. The speed change stage setting portion63sets the usable speed change stages of the main speed change device30and the auxiliary speed change device31via the procedure described with reference toFIGS. 2 and 3.

The display control portion or controller8, in conjunction with the notification processor803and the like, configures a speed change display control device and includes a display screen generator81generating the first display screen101, the second display screen200, and the third display screen (engaged speed change stage selection screen)300. A description of the first display screen101and the second display screen200was previously given with reference toFIG. 2, and a description of the third display screen (engaged speed change stage selection screen)300was previously given with reference toFIG. 3. In addition, the speed change range selected via the second display screen200and the third display screen300is provided to the speed change controller6and can be used as a limitation on the speed change stages used in the speed change control.

The travel status determiner60determines whether the work vehicle is in the work travel state or the road travel state based on detection signals from at least one status detection sensor from the group of status detection sensors90, which detect the status of the work vehicle, the detection signals being obtained via the input signal processor802. When a determination is made that the work vehicle is in the work travel state, the work travel mode is set on the speed change controller6, and when a determination is made that the work vehicle is in the road travel state, the road travel mode is set.

The work controller7A performs control of the work apparatus22based on signals from the work-related operation switch group9. The work controller7A also manages setting the upper limit of the work apparatus22and a lifting and lowering speed of the work apparatus22. The work travel support portion7B manages warnings and the like, as well as notifications to the driver, based on partial automation of the work travel or on signals from the group of status detection sensors90.

OTHER EMBODIMENTS

(1) In the above-described embodiment, the main speed change stage display area201and the auxiliary speed change stage display area202were configured by semicircular bar graphs centered on the same point. However, each auxiliary speed change stage and all of the main speed change stages may also be assigned to one side of a halved polygonal bar graph.
(2) The display13may be arranged at a location other than the armrest operation device4. In addition, a plurality of the displays13may be included or utilized, which may be configured so as to mirror each other.
(3) The functional blocks inFIG. 10are merely for illustration purposes. The respective functional components can be consolidated or divided as desired. In particular, the various functions configuring the calculation control device800are linked to each other by software, and therefore in many practical cases there is overlap in these portions or functions. The functions shown inFIG. 10are shown only schematically, and the distinctions are not limited thereby.

In addition to a tractor, the traveling work vehicle according to the present invention may also be applied to an agricultural work vehicle such as a rice transplanter or combine, or to a construction and engineering vehicle such as a front loader.