JP7809658B2 - Transmission mechanism and agricultural vehicle - Google Patents

Description

The present invention relates to a transmission mechanism and an agricultural vehicle.

Agricultural vehicles are equipped with transmissions. For example, the transmission of a rice transplanter has four gears: neutral, planting speed when planting seedlings, transport speed used mainly for traveling outside the field, and reverse. Traditionally, gears have been changed by sliding a slide gear via a link or wire connected to an operating tool. However, in muddy fields, for example, large torque is applied, making it difficult to disengage the slide gear, and operating the operating tool requires a lot of effort. Therefore, technologies to reduce the effort required for gear-changing have been studied. For example, Patent Document 1 proposes activating an actuator to slide the slide gear in response to the operation of the operating tool.

Japanese Patent Application Laid-Open No. 2019-202632

However, using an actuator to switch between all gear stages requires a large actuator stroke, which could result in an increase in the size of the device. Furthermore, while gear changes between planting speed, neutral, and reverse speed are frequent, gear changes between planting speed and moving speed are infrequent, so there is little need to use an actuator. Furthermore, the sliding gear travels a longer distance between planting speed and moving speed than between planting speed, neutral, and reverse speed, so gear changes can be made more quickly by sliding the sliding gear via a link or wire than by using an actuator.

In consideration of the above circumstances, the present invention aims to provide a transmission mechanism and agricultural vehicle that can selectively change gears using an actuator or load transmission from the operating tool using the same operating tool.

To solve the above problem, the transmission mechanism of the present invention includes a stepped transmission; an operating device that can be operated to multiple positions corresponding to the multiple gear stages of the stepped transmission; a transmission unit that switches the gear stages of the stepped transmission by transmitting a load from the operating device when the operating device is operated between a first position and a second position of the multiple positions; a first detection unit that detects the position of the operating device; and an actuator that switches the gear stages of the stepped transmission in accordance with the position detected by the first detection unit when the operating device is operated between the first position and a third position of the multiple positions.

The speed change mechanism may include an engagement portion that engages the operating tool with the transmission portion, and the engagement portion may be switched between an engaged state and a disengaged state by operating the operating tool.

The gear shift mechanism may include a second detector that detects when the operating tool is operated from the third position to the fourth position, and a controller that performs control other than gear shifting when the operating tool is detected by the second detector.

The first position, the second position, and the third position may correspond to a planting speed, a moving speed, and a neutral position, respectively.

The speed change mechanism may include a rod that transmits the load generated by the actuator to the stepped transmission, and the rod may include an elastic member that expands and contracts in the longitudinal direction of the rod, a pair of rod members that are provided at both ends of the elastic member with their axes aligned, and a guide member that guides the expansion and contraction of the elastic member.

The agricultural work vehicle according to the present invention may also include any of the above-described transmission mechanisms and a running body that runs using the driving force transmitted from the transmission mechanism.

The agricultural work vehicle may be equipped with a work implement that operates when the operating tool is located in the first position and does not operate when the operating tool is located in the second position.

According to the present invention, it is possible to selectively use the same operating tool to change speeds by an actuator or by load transmission from the operating tool.

1 is a left side view showing an agricultural work vehicle according to an embodiment of the present invention. FIG. 1 is a plan view showing an agricultural work vehicle according to an embodiment of the present invention. 1 is a plan view showing a power transmission mechanism 20 of an agricultural work vehicle according to an embodiment of the present invention. 1 is a plan view showing a manipulating tool and its peripheral parts according to an embodiment of the present invention. 1 is a perspective view showing a speed change mechanism according to an embodiment of the present invention; 1 is a perspective view showing a speed change mechanism according to an embodiment of the present invention; 1 is a perspective view showing a speed change mechanism according to an embodiment of the present invention; 1 is a perspective view showing a speed change mechanism according to an embodiment of the present invention; 1 is a perspective view showing a speed change mechanism according to an embodiment of the present invention; 1 is a perspective view showing a speed change mechanism according to an embodiment of the present invention; 1 is a perspective view showing a speed change mechanism according to an embodiment of the present invention; 1 is a cross-sectional view showing a ball clutch according to an embodiment of the present invention. 1 is a plan view showing a stepped transmission according to an embodiment of the present invention; 1 is a plan view showing a stepped transmission according to an embodiment of the present invention; 1 is a plan view showing a stepped transmission according to an embodiment of the present invention; 1 is a plan view showing a stepped transmission according to an embodiment of the present invention; 1 is a diagram illustrating a power transmission mechanism of a transmission according to an embodiment of the present invention. 1 is a cross-sectional view showing a ball clutch according to an embodiment of the present invention. 1 is a cross-sectional view showing a ball clutch according to an embodiment of the present invention. FIG. 4 is a plan view showing a second detection unit according to an embodiment of the present invention. FIG. 4 is a plan view showing a second detection unit according to an embodiment of the present invention.

The agricultural work vehicle 1 according to one embodiment of the present invention will be described below with reference to the drawings.

First, the overall configuration of the agricultural work vehicle 1 will be described. Fig. 1 is a left side view showing the agricultural work vehicle 1. Fig. 2 is a plan view showing the agricultural work vehicle 1. Fig. 3 is a plan view showing the power transmission mechanism 20 of the agricultural work vehicle 1. In each figure, U, Lo, L, R, Fr, and Rr indicate up, down, left, right, front, and rear, respectively.

The agricultural work vehicle 1 (see Figures 1 to 3) comprises a running body 2 and a working implement 3 provided behind the running body 2. For example, the working implement 3 is a planting device that plants rice seedlings, and the agricultural work vehicle 1 is a rice transplanter that plants seedlings using the working implement 3 while traveling on the running body 2. The working implement 3 may also be a device that transplants vegetables or grains, sows seeds, tills, etc.

The vehicle 2 includes a body frame 10, a drive source 11 and a transmission 12 provided in the center of the front of the body frame 10 in the left-right direction, a pair of left and right front wheels 13 provided in the front of the body frame 10, and a pair of left and right rear wheels 14 provided in the rear of the body frame 10.

The drive source 11 generates driving force to drive the front wheels 13 and rear wheels 14. The drive source 11 is, for example, an internal combustion engine fueled by diesel, and is covered by a hood 21. The transmission 12 (see Figure 3) is provided behind the drive source 11 and changes the speed of the driving force generated by the drive source 11. Front axles 19 are provided on the left and right of the transmission 12. The front wheels 13 are attached to front axles 19S provided on the front axle 19, and are driven by driving force transmitted from the transmission 12.

The rear axle 24 is located behind the transmission 12 and is connected to the transmission 12 by a joint member 23 whose longitudinal direction is in the fore-and-aft direction. The rear wheel drive shaft 25 is located along the joint member 23 and transmits driving force from the transmission 12 to the rear axle 24. The rear wheels 14 are attached to rear axles 24S located on the rear axle 24 and are driven by driving force transmitted via the rear wheel drive shaft 25. Note that crawlers (not shown) may be provided instead of the rear wheels 14.

The driver's seat 15 is located above the joint material 23. Around the driver's seat 15, there are a steering handle 16, operating tools 40, a speed change pedal 37, a brake pedal (not shown), etc. The front wheels 13 steer the running body 2 in conjunction with the operation of the steering handle 16. Steps 17 (see Figure 2) are flat members that serve as footholds for the operator, and are provided around the driver's seat 15 and on the left and right sides of the hood 21. Spare seedling trays 18 are provided on the left and right sides of the hood 21, and are used to place seedling mats to be replenished in the work machine 3. The operating tools 40 are, for example, a speed change lever, and are used to operate the speed change mechanism 4, which will be described later.

The inter-section transmission 27 (see Figure 3) is located above the rear axle 24, to the right of the center in the left-right direction. The inter-section transmission 27 changes the speed of the driving force input from the transmission 12 via drive shaft 35A and outputs it to the work implement 3 via drive shaft 35B.

The work machine 3 comprises a seedling carrier 30 on which the seedling mat is placed, and a main frame 31. The main frame 31 is a rod-shaped member with its longitudinal direction in the left-right direction and has a center case 33 in the left-right center. Planting transmission cases 34 are provided at approximately equal intervals at multiple locations (four locations in this example) in the left-right direction behind the main frame 31. A pair of left and right transplanting mechanisms 32 are provided in the planting transmission cases 34.

A drive shaft 35B is connected to the input shaft 33A of the center case 33 via a universal joint. The center case 33 is equipped with a gear train (not shown) including a bevel gear. The output shaft 33B of the center case 33 is mounted along the main frame 31 and connected to each planting transmission case 34. Driving force is transmitted to the transplanting mechanism 32 via the drive shaft 35B, center case 33, and planting transmission case 34. The work machine 3 is equipped with a lateral feed drive unit (not shown) that drives the seedling carrier 30 to move laterally. In parallel with the seedling carrier 30 reciprocating left and right, the transplanting mechanism 32 removes seedlings from the seedling carrier 30 and plants them in the field.

The work implement 3 is equipped with a lifting device 22. The lifting device 22 comprises a columnar frame 10P, a pair of parallel upper and lower link members 22L, and a hydraulic cylinder 22C. The vehicle frame 10 is supported by the columnar frame 10P located above the rear axle 24. The columnar frame 10P and the seedling carrier 30 are connected by a pair of link members 22L. The nodes between the columnar frame 10P, the seedling carrier 30, and the pair of link members 22L form the four vertices of a parallelogram. The hydraulic cylinder 22C is connected to the joint material 23 and the lower link member 22L. As the hydraulic cylinder 22C expands and contracts, the pair of link members 22L swing around the node on the columnar frame 10P side as a fulcrum, raising and lowering the seedling carrier 30.

Next, the speed change mechanism 4 will be described. Figure 4 is a plan view showing the operating tool 40 and its surrounding area. Figures 5 to 11 are perspective views showing the speed change mechanism 4. Figures 12, 18, and 19 are cross-sectional views showing the ball clutch 55. Figures 13 to 16 are plan views showing the stepped transmission 12M. Figure 17 is a diagram of the transmission mechanism of the transmission 12. Figures 13, 14, 15, and 16 show the states in which the gear stages of the stepped transmission 12M are travel speed, planting speed, neutral, and reverse speed, respectively.

The transmission mechanism 4 according to this embodiment includes a stepped transmission 12M, an operating device 40 that can be operated to multiple positions corresponding to the multiple gear stages of the stepped transmission 12M, a transmission unit 80 that switches the gear stage of the stepped transmission 12M by transmitting a load from the operating device 40 when the operating device 40 is operated between a first position F1 and a second position F2 of the multiple positions, a first detector 471 that detects the position of the operating device 40, and an actuator 60 that switches the gear stage of the stepped transmission 12M in accordance with the position detected by the first detector 471 when the operating device 40 is operated between a first position F1 and a third position N of the multiple positions. Specifically, the components are as follows:

<Stepped transmission>
The stepped transmission 12M (see FIGS. 13 to 17) includes an input shaft 50, an input fork shaft 61, an output shaft 70, and an output fork shaft 81. The output fork shaft 81 constitutes a part of a transmission unit 80. The input shaft 50, the input fork shaft 61, the output shaft 70, and the output fork shaft 81 are arranged parallel to one another with their axial directions extending in the left-right direction, and are supported by bearings (not shown) provided in the housing of the transmission 12.

<Input shaft>
The input shaft 50 is equipped with a planting speed gear 51, a moving speed gear 52, a reverse speed gear 53, and a ball clutch 55. The driving force generated by the drive source 11 is transmitted to the input shaft 50 via an HST 12H (hydrostatic continuously variable transmission), a planetary gear mechanism 12P, and a main clutch 12C (see Figure 17). A cylindrical connecting member 51J is fitted onto the input shaft 50. The planting speed gear 51 and the moving speed gear 52 are fitted onto the connecting member 51J and integrated.

The ball clutch 55 (see Figure 12) includes a shifter 55S, balls 55B, and a ball engagement member 55E. The ball engagement member 55E is an annular member provided on the outer peripheral surface of the input shaft 50. The outer peripheral surface of the ball engagement member 55E is provided with two recess rows 55U, one on the left and one on the right, each circumferentially arranged with multiple recesses for accommodating the balls 55B. Note that Figure 12 shows only one recess included in the right recess row 55U. Because the left and right recess rows 55U are located at different circumferential positions, the left recess row 55U is not shown.

A sleeve 51S that surrounds the input shaft 50 is coupled to the left end of the coupling member 51J. The sleeve 51S has multiple through holes 51H that correspond to the right-side recessed row 55U. A sleeve 53S that surrounds the input shaft 50 is coupled to the right end of the reverse gear 53. The sleeve 53S has multiple through holes 53H that correspond to the left-side recessed row 55U.

The right end of the shifter 55S contacts the outer peripheral surface of the sleeve 51S. The left end of the shifter 55S contacts the outer peripheral surface of the sleeve 53S. An annular cavity 55V is provided in the center of the shifter 55S in the left-right direction. The shifter 55S can slide left and right.

Figures 12 and 15 show the case where the shifter 55S is positioned in the center. In this case, the balls 55B are released from the left and right recess rows 55U into the cavities 55V of the shifter 55S, so neither the planting speed gear 51 nor the reverse speed gear 53 is connected to the input shaft 50.

When the shifter 55S slides to the left (see Figures 13, 14, and 18), the right end of the shifter 55S pushes the ball 55B into the right-side recess row 55U, connecting the planting speed gear 51 to the input shaft 50. At this time, centrifugal force causes the ball 55B to be released from the left-side recess row 55U into the cavity 55V of the shifter 55S, so the reverse speed gear 53 is not connected to the input shaft 50.

When the shifter 55S slides to the right (see Figures 16 and 19), the left end of the shifter 55S pushes the ball 55B into the left-side recess row 55U, connecting the reverse speed gear 53 to the input shaft 50. At this time, centrifugal force causes the ball 55B to be released from the right-side recess row 55U into the cavity 55V of the shifter 55S, so the planting speed gear 51 is not connected to the input shaft 50.

<Input side fork shaft>
The input side fork shaft 61 (see FIGS. 13 to 16 ) includes a fork 62, a pivot 63, and a rod 64, and is slidable in the left-right direction. The fork 62 is coupled to the shifter 55S. The rod 64 is disposed rearward of the right end of the input side fork shaft 61, with its axial direction extending in the front-to-rear direction. The pivot 63 includes a fulcrum 63S, an arm 63A protruding toward the rod 64, and an arm 63B protruding toward the input side fork shaft 61, and is swingable clockwise and counterclockwise around the fulcrum 63S in FIG. 15 . A groove is formed on the right end of the input side fork shaft 61. The tip of the arm 63B is housed in the groove. The tip of the arm 63A is swingably coupled to the front end of the rod 64. The rear end of the rod 64 is connected to the actuator 60.

When the actuator 60 slides the rod 64 forward (see Figure 16), the pivot 63 swings clockwise, causing the input fork shaft 61 to slide to the right together with the shifter 55S. When the actuator 60 slides the rod 64 rearward (see Figures 13 and 14), the pivot 63 swings counterclockwise, causing the input fork shaft 61 to slide to the left together with the shifter 55S.

The rod 64 (see Figures 13 to 16) comprises an elastic member 64E, a pair of rod members 64R provided at both ends of the elastic member 64E with their axes aligned, and a guide member 64G that guides the expansion and contraction of the elastic member 64E. The elastic member 64E is, for example, a coil spring. The rod member 64R is, for example, a turnbuckle, and its length is adjustable. The guide member 64G is, for example, a cylindrical member that surrounds the elastic member 64E and the connection between the elastic member 64E and the rod member 64R. The rod member 64R is slidable along the inner surface of the guide member 64G.

In the aforementioned ball clutch 55, when the ball 55B is positioned on the cavity 55V side, the circumferential position of the ball 55B does not necessarily coincide with the position of the recessed row 55U. This means that it takes some time from the start of sliding of the shifter 55S until the ball 55B is accommodated in the recessed row 55U. Therefore, if the rod 64 is not extendable, there is a problem in that gears cannot be shifted until the ball 55B is accommodated. In this embodiment, when the rod 64 is pushed in, the compressed elastic member 64E continues to apply a load in a pushing direction to the pivot 63 until the ball 55B is accommodated in the recessed row 55U. On the other hand, when the rod 64 is retracted, the expanded elastic member 64E continues to apply a load in a pulling direction to the pivot 63 until the ball 55B is accommodated in the recessed row 55U. In this way, the elastic member 64E retains elastic energy during gear shifting, causing a load to continue to act on the shifter 55S, so when the phases of the recessed row 55U and the ball 55B are aligned, the ball 55B is pushed into the recessed row 55U, and the gear shift is performed.

<Output shaft>
The output shaft 70 includes a slide gear 71 and a brake 72. The slide gear 71 includes a planting speed gear 711 and a moving speed gear 712. The slide gear 71 is connected to the output shaft 70 by a spline (not shown) and is slidable in the left-right direction.

<Output fork shaft, transmission section>
The output fork shaft 81 includes a fork 82, a pivot 83, and a rod 84, and is slidable in the left-right direction. The fork 82 is coupled to the slide gear 71. The rod 84 is disposed rearward of the left end of the output fork shaft 81, with its axial direction extending in the front-to-rear direction. The pivot 83 includes a fulcrum 83S, an arm 83A protruding toward the rod 84, and an arm 83B protruding toward the output fork shaft 81. The pivot 83 is capable of swinging clockwise and counterclockwise around the fulcrum 83S in FIG. 15 . A groove (not shown) is formed in the left end of the output fork shaft 81. The tip of the arm 83B is housed in the groove. The tip of the arm 83A is swingably coupled to the rear end of a rod 84 disposed along the front-to-rear direction. The front end of the rod 84 is connected to the auxiliary transmission arm 42 (described later) via a rod, wire, or the like (not shown).

When the rod 84 is slid forward (see Figure 13), the pivot 83 swings clockwise, causing the output fork shaft 81 to slide to the right together with the slide gear 71. When the rod 84 is slid rearward (see Figures 14 to 16), the pivot 83 swings counterclockwise, causing the output fork shaft 81 to slide to the left together with the slide gear 71.

<Operating tools>
The operating tool 40 (see FIGS. 4 to 11) is a shift lever that can be operated to a plurality of positions corresponding to the plurality of gears of the stepped transmission 12M. A slit 46S that guides the position movement of the operating tool 40 is provided in a dashboard 46 provided in front of the driver's seat 15. The shape of the slit 46S may be different from that shown in the drawings.

The first position F1 corresponds to the planting speed and is used when planting seedlings in a field using the implement 3. The second position F2 corresponds to the travel speed and is mainly used for travel outside the field. The third position N corresponds to neutral, in which no driving force is transmitted from the input shaft 50 to the output shaft 70. The fourth position S remains in neutral, allowing for specific control (e.g., seedling feeding). The fifth position R corresponds to reverse travel.

Figure 10 shows the gear position of the stepped transmission 12M in neutral. The first fulcrum 411 is disposed with its axial direction aligned in the left-right direction and is fixed to the vehicle frame 10. The operating tool 40 is a rod-shaped member with its longitudinal direction aligned in the up-down direction. The lower end of the operating tool 40 is supported by the first fulcrum 411 and can swing back and forth around the first fulcrum 411. The upper end of the operating tool 40 is spherical and can be gripped by the operator. A second fulcrum 412 is provided above the first fulcrum 411 of the operating tool 40, with its axial direction aligned in a direction intersecting the first fulcrum 411. The operating tool 40 can swing left and right around the second fulcrum 412.

The detent arm 43 is swingably supported on the first fulcrum 411 and swings together with the operating tool 40. A U-shaped leaf spring 45 is provided at the front end of the detent arm 43. The front end of the leaf spring 45 is a fixed end and is attached to the detent arm 43. The rear end of the leaf spring 45 is a free end and is provided with a pin 45P whose axial direction is in the left-right direction.

The detent plate 44 is fixed to the vehicle body frame 10 and faces the rear of the leaf spring 45. The detent plate 44 is formed in an arc shape centered on the first fulcrum 411. The front edge of the detent plate 44 is provided with, in order from bottom to top, a first groove 441, a second groove 442, and a third groove 443. The first groove 441 corresponds to the first position F1. The second groove 442 corresponds to the third position N. The third groove 443 corresponds to the fifth position R. The pin 45P fits into the first groove 441, the second groove 442, and the third groove 443, imparting a clicking sensation to the operation of the operating device 40.

The sub-transmission arm 42 is supported by the first fulcrum 411, but can swing independently of the operating tool 40. The sub-transmission arm 42 is connected to the rod 84 via a rod, wire, or the like. An arm engaging portion 42A is provided at the tip of the sub-transmission arm 42. The arm engaging portion 42A is, for example, a protrusion that projects to the left. Meanwhile, the operating tool 40 is provided with an operating tool engaging portion 40A at a position corresponding to the arm engaging portion 42A. The operating tool engaging portion 40A is a hole through which the arm engaging portion 42A can enter.

When the arm engagement portion 42A and the operating tool engagement portion 40A are opposed to each other in the left-right direction (see Figure 7), swinging the operating tool 40 to the right about the second fulcrum 412 engages the arm engagement portion 42A and the operating tool engagement portion 40A (see Figure 6), allowing the sub-speed-change arm 42 to swing together with the operating tool 40. When the arm engagement portion 42A and the operating tool engagement portion 40A are not opposed to each other in the left-right direction, the arm engagement portion 42A and the operating tool engagement portion 40A cannot engage, and therefore the sub-speed-change arm 42 cannot swing together with the operating tool 40.

In short, the sub-transmission arm 42, rod 84, pivot 83, fork 82, and output fork shaft 81 constitute the transmission unit 80. When the operating device 40 is operated between a first position F1 and a second position F2 among a plurality of positions, the transmission unit 80 switches the gear position of the stepped transmission 12M by transmitting a load from the operating device 40.

<First detection unit>
The first detector 471 is a position switch that detects the position of the operating tool 40. The operating tool 40 is provided with a detection lever 40B that protrudes downward. The first detector 471 clamps the detection lever 40B and detects the position of the operating tool 40 from the attitude of the detection lever 40B.

<Second detection unit>
The second detector 472 is provided on the inside of the dashboard 46 (see FIG. 4 ). The second detector 472 detects when the operating tool 40 moves from the third position N to the fourth position S. FIGS. 20 and 21 are plan views showing the second detector 472. The second detector 472 is, for example, a microswitch including a main body 472M with a circuit (not shown), a lever 472L, and an actuator 472A. When the actuator 472A is pressed via the lever 472L, the circuit is energized. The second detector 472 is provided to the right of the fourth position S. When the operating tool 40 is located at the third position N (see FIG. 20 ), the operating tool 40 does not contact the lever 472L, so the actuator 472A is not pressed and no current is applied to the circuit. When the operating tool 40 moves to the fourth position S (see Figure 21), the operating tool 40 presses the lever 472L to the right, which pushes the actuator 472A and energizes the circuit, thereby detecting that the operating tool 40 has moved to the fourth position S.

Next, the operation of the transmission mechanism 4 will be described. Here, the initial state will be described as the neutral gear position (see Figures 10 and 15). The operating device 40 is located in third position N. The pin 45P provided on the leaf spring 45 of the detent arm 43 is engaged with the second groove 442 of the detent plate 44. The first detector 471 detects that the operating device 40 is located in third position N. Because the shifter 55S of the ball clutch 55 is located in the center, neither the planting speed gear 51 nor the reverse speed gear 53 is connected to the input shaft 50.

Next, when the operating tool 40 is operated to first position F1 (see Figure 8), the pin 45P moves into the first groove 441, and the first detector 471 detects that the operating tool 40 is in first position F1. The actuator 60 then retracts the rod 64 (see Figure 14), causing the input fork shaft 61 to slide to the left together with the shifter 55S. As the shifter 55S slides to the left, the planting speed gear 51 connects to the input shaft 50, and driving force is transmitted to the planting speed gear 711 of the output shaft 70, causing the agricultural work vehicle 1 to move forward at planting speed.

Next, when the operating tool 40 is operated further forward from the first position F1 (see Figure 7), the arm engagement portion 42A and the operating tool engagement portion 40A face each other in the left-right direction.

Next, when the operating tool 40 is operated to the left around the second fulcrum 412 (see Figure 6), the arm engagement portion 42A and the operating tool engagement portion 40A engage.

Next, when the operating tool 40 is operated to second position F2 (see Figure 5), the pin 45P disengages from the first groove 441 and moves downward, and the first detector 471 detects that the operating tool 40 is in second position F2. At this time, the sub-transmission arm 42 swings forward, causing the rod 84 to slide forward (see Figure 13), and the pivot 83 swings clockwise, causing the output fork shaft 81 to slide to the right together with the slide gear 71. As a result, the planting speed gear 711 disengages from the planting speed gear 51 and the moving speed gear 712 connects to the moving speed gear 52, causing the agricultural work vehicle 1 to move forward at moving speed.

On the other hand, when the operating tool 40 is operated from the third position N (neutral) to the fourth position S (see Figure 9), the second detector 472 detects that the operating tool 40 is in the fourth position S. The controller 5 (see Figure 4) then executes a control different from a gear change, such as control for seedling transfer. In this case, the gear remains neutral, and control is executed to operate the work implement 3 at a predetermined speed, for example.

On the other hand, when the operating device 40 is operated from the third position N to the fifth position R (see FIG. 11), the pin 45P moves from the second groove 442 to the third groove 443, and the first detector 471 detects that the operating device 40 is located at the fifth position R. The actuator 60 then pushes out the rod 64 (see FIG. 16), causing the input fork shaft 61 to slide to the right together with the shifter 55S. As the shifter 55S slides to the right, the reverse speed gear 53 connects to the input shaft 50, and driving force is transmitted to the output shaft 70 via the reverse gear (not shown), causing the agricultural work vehicle 1 to move backward at reverse speed.

The transmission mechanism 4 according to the present embodiment described above includes a stepped transmission 12M, an operating device 40 that can be operated to multiple positions corresponding to the multiple gear stages of the stepped transmission 12M, a transmission unit 80 that switches the gear stage of the stepped transmission 12M by transmitting a load from the operating device 40 when the operating device 40 is operated between a first position F1 and a second position F2 of the multiple positions, a first detection unit 471 that detects the position of the operating device 40, and an actuator 60 that switches the gear stage of the stepped transmission 12M in accordance with the position detected by the first detection unit 471 when the operating device 40 is operated between a first position F1 and a third position N of the multiple positions.

With this configuration, the same operating device 40 can be used to selectively change gears using the actuator 60 or by load transmission from the operating device 40. For example, the actuator 60 can be used for shifting between frequently used gear stages (between first position F1 and third position N) that require a large torque, while the load from the operating device 40 can be used for shifting between less frequently used gear stages (between first position F1 and second position F2). This reduces the effort required for shifting gears and prevents the device from becoming too large.

The speed change mechanism 4 according to this embodiment is equipped with an arm engagement portion 42A and an operating device engagement portion 40A (an example of an engagement portion) that engage the operating device 40 with the transmission unit 80, and the engagement portion can be switched between an engaged state and a disengaged state by operating the operating device 40. With this configuration, it is possible to select either the transmission unit 80 or the actuator 60 by operating the operating device 40.

The gear change mechanism 4 according to this embodiment also includes a second detector 472 that detects when the operating device 40 is operated from the third position N to the fourth position S, and a controller 5 that executes control other than gear shifting when the operating device 40 is detected by the second detector 472. With this configuration, control other than gear shifting can be executed by operating the operating device 40.

Furthermore, with the transmission mechanism 4 according to this embodiment, the first position F1, second position F2, and third position N correspond to the planting speed, moving speed, and neutral, respectively. This configuration allows the transmission unit 80 and the actuator 60 to be used selectively depending on the frequency of use of the gear stage.

The transmission mechanism 4 according to this embodiment also includes a rod 64 that transmits the load generated by the actuator 60 to the stepped transmission 12M. The rod 64 includes an elastic member 64E that expands and contracts in the longitudinal direction of the rod 64, a pair of rod members 64R that are aligned with each other and are provided at both ends of the elastic member 64E, and a guide member 64G that guides the expansion and contraction of the elastic member 64E. With this configuration, the elastic energy held by the elastic member 64E can be used to continue applying a load to the stepped transmission 12M until the gear shift is complete. Therefore, when using a gear shifting device that delays gear shifting relative to the operation of the actuator 60, such as a ball clutch 55, the load on the actuator 60 can be reduced.

The agricultural work vehicle 1 according to this embodiment is equipped with any one of the above-described transmission mechanisms 4 and a running body 2 that runs using the driving force transmitted from the transmission mechanism 4. With this configuration, the agricultural work vehicle 1 can be run using the same operating tool 40, while selectively switching between speed changes using the actuator 60 and speed changes using load transmission from the operating tool 40.

Furthermore, the agricultural work vehicle 1 according to this embodiment is equipped with a work implement 3 that operates when the operating tool 40 is located in the first position F1 and does not operate when the operating tool 40 is located in the second position F2. With this configuration, the operation of the work implement 3 can be switched between on and off in conjunction with the operation of the operating tool 40.

<Additional Notes>
The present invention can be specified as follows.

<Appendix 1>
A stepped transmission and
an operating tool that can be operated to a plurality of positions corresponding to a plurality of gear stages of the stepped transmission;
a transmission unit that switches the gear position of the stepped transmission by transmitting a load from the operating tool when the operating tool is operated between a first position and a second position among the plurality of positions;
a first detector that detects the position of the operating tool;
an actuator that switches the gear position of the stepped transmission in accordance with the position detected by the first detection unit when the operating tool is operated between the first position and a third position among the plurality of positions.

<Appendix 2>
an engaging portion that engages the operating tool with the transmission portion,
2. The transmission mechanism according to claim 1, wherein the engaging portion is switched between an engaged state and a disengaged state by operating the operating tool.

<Appendix 3>
a second detection unit that detects that the operating tool has been operated from the third position to a fourth position;
3. The transmission mechanism according to claim 1, further comprising: a control unit that executes control other than a gear change when the second detection unit detects the operating tool.

<Appendix 4>
4. The transmission mechanism according to claim 1, wherein the first position, the second position, and the third position correspond to a planting speed, a moving speed, and a neutral position, respectively.

<Appendix 5>
a rod that transmits the load generated by the actuator to the stepped transmission;
The rod is
an elastic member that expands and contracts in the longitudinal direction of the rod;
a pair of rod members provided at both ends of the elastic member with their axes aligned;
5. The speed change mechanism according to claim 1, further comprising: a guide member that guides the expansion and contraction of the elastic member.

<Appendix 5>
A transmission mechanism according to any one of claims 1 to 4;
a running body that runs using the driving force transmitted from the transmission mechanism.

<Appendix 6>
6. The agricultural work vehicle according to claim 5, further comprising a work implement that operates when the operating tool is located at the first position and does not operate when the operating tool is located at the second position.

1 Agricultural work vehicle 2 Traveling body 3 Work machine 4 Transmission mechanism 5 Control unit 12M Stepped transmission 40 Operating tool 40A Operating tool engagement portion (engagement portion)
42A Arm engagement portion (engagement portion)
64 Rod 64E Elastic member 64R Rod member 64G Guide member 471 First detection portion 472 Second detection portion 60 Actuator 80 Transmission portion

Claims (7)

A stepped transmission and
an operating tool that can be operated to a plurality of positions corresponding to a plurality of gear stages of the stepped transmission;
a transmission unit that switches the gear position of the stepped transmission by transmitting a load from the operating tool when the operating tool is operated between a first position and a second position among the plurality of positions;
a first detector that detects the position of the operating tool;
an actuator that switches the gear position of the stepped transmission in accordance with the position detected by the first detection unit when the operating tool is operated between the first position and a third position among the plurality of positions. an engaging portion that engages the operating tool with the transmission portion,
2. The transmission mechanism according to claim 1, wherein the engaging portion is switched between an engaged state and a disengaged state by operating the operating tool. a second detection unit that detects that the operating tool has been operated from the third position to a fourth position;
3. The transmission mechanism according to claim 1, further comprising: a control unit that executes control other than a gear change when the second detection unit detects the operating tool. The transmission mechanism of claim 1, wherein the first position, the second position, and the third position correspond to planting speed, moving speed, and neutral, respectively. a rod that transmits the load generated by the actuator to the stepped transmission;
The rod is
an elastic member that expands and contracts in the longitudinal direction of the rod;
a pair of rod members provided at both ends of the elastic member with their axes aligned;
2. The transmission mechanism according to claim 1, further comprising a guide member that guides the expansion and contraction of the elastic member. The transmission mechanism according to claim 1;
a running body that runs using the driving force transmitted from the transmission mechanism. The agricultural work vehicle described in claim 6, further comprising a work implement that operates when the operating tool is located in the first position and does not operate when the operating tool is located in the second position.