Work vehicle

Abstract

To provide a work vehicle capable of easily changing the height of a positioning device in order to solve such a problem that even though a work vehicle is known that levels a field by being provided with a positioning control mode in which the positioning device for measuring height position information of a work machine is mounted on a top link, and the lifting position of the work machine is controlled on the basis of positioning information obtained by the positioning device, conventionally, it has been necessary to change the reference height of the positioning device using a setting device.SOLUTION: In a work vehicle in which a work machine W is mounted on a traveling vehicle body 2 so as to be liftable by a lifting device 12, a positioning device 31 for measuring the vertical position of the work machine W is provided on a slide hitch 37 whose vertical position can be changed by a vertical position adjustment mechanism 39 of the work machine W, and a control device 20 is provided to control the lifting device 12 so that the work machine W reaches a predetermined height on the basis of height position information obtained from the positioning device 31.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a work vehicle such as a tractor equipped with an agricultural work implement. [Background technology]

[0002] A work vehicle that levels farm fields is known, and has a positioning device on the top link that measures the height position information of the work implement, and a positioning control mode that controls the lifting position of the work implement based on the positioning information obtained by the positioning device (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-193898 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, it has been necessary to change the reference height of the positioning device using a setting device.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a work vehicle in which the height of a positioning device can be easily changed. [Means for solving the problem]

[0006] The invention described in claim 1 is a work vehicle in which a work implement W is attached to a running body 2 so that it can be raised and lowered freely by a lifting device 12, a positioning device 31 that measures the vertical position of the work implement W is provided on a slide hitch 37 whose vertical position can be changed freely by a vertical position adjustment mechanism 39 of the work implement W, and a control device 20 that controls the lifting device 12 so that the work implement W is at a predetermined height based on height position information obtained from the positioning device 31.

[0007] According to the invention described in claim 1, a positioning device 31 that measures the vertical position of the work implement W is provided on a slide hitch 37 whose vertical position can be freely changed by a vertical position adjustment mechanism 39 of the work implement W, and a control device 20 is provided that controls the lifting device 12 based on height position information obtained from the positioning device 31 so that the work implement W reaches a predetermined height.Therefore, the height of the positioning device 31 can be changed by the vertical position adjustment mechanism 39 that changes the vertical position of the slide hitch 37.

[0008] The invention described in claim 2 is a work vehicle described in claim 1 in which the positioning device bracket 38 for mounting the positioning device 31 to the slide hitch 37 is composed of a mounting portion 38a for mounting to the slide hitch 37, an arm 38b extending forward from the mounting portion 38a, and a support stay 38c for mounting the positioning device 31 provided at the tip of the arm 38b.

[0009] According to the invention described in claim 2, the positioning device bracket 38 for attaching the positioning device 31 to the slide hitch 37 is composed of an attachment part 38a for attaching to the slide hitch 37, an arm 38b extending forward from the attachment part 38a, and a support stay 38c for attaching the positioning device 31 provided at the tip of the arm 38b.Therefore, the work equipment positioning device 31 is positioned forward of the attachment part 38a for attaching to the slide hitch 37 of the positioning device bracket 38, making it possible to prevent it from being hit by mud kicked up by the work equipment W, and also being positioned forward and away from the rear end of the slide hitch 37, it is less susceptible to the effects of vibrations generated when the work equipment W is operating.

[0010] The invention described in claim 3 is a work vehicle described in claim 1 or claim 2 in which an unlock detection sensor is provided in the suspension device 50 of the lifting device 12 to detect the unlocked state of the locking mechanism 51 that locks the connection of the work implement W attached to the suspension device 50, and when the unlock detection sensor detects the unlocked state, it alerts the driver when it detects that the wiring 32 connecting the positioning device 31 and the control device 20 is connected.

[0011] According to the invention described in claim 3, an unlock detection sensor is provided in the suspension device 50 of the lifting device 12 to detect the unlocked state of the locking mechanism 51 that locks the connection of the work machine W attached to the suspension device 50. Therefore, when attaching or detaching the work machine W to or from the suspension device 50, there is no need to take the time to attach or detach the wiring connecting the unlock detection sensor to the control device 20, which improves workability.

[0012] In addition, when the unlock detection sensor detects an unlocked state, it issues an alert when it detects that the wiring 32 connecting the positioning device 31 and the control device 20 is connected, thereby preventing damage caused by forgetting to unplug the wiring 32 when removing the work machine W from the suspension device 50. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a left side view of a work vehicle according to an embodiment of the present invention. [Figure 2] 1 is a right side view of a working machine according to an embodiment of the present invention. [Figure 3] 1 is a left side view of a working machine according to an embodiment of the present invention. [Figure 4] 1 is a perspective view of a working machine according to an embodiment of the present invention; [Figure 5] 1 is a plan view of a working machine according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] A tractor 1 equipped with an agricultural work implement W, which is an embodiment of a work vehicle disclosed in the present application, will be described in detail with reference to the accompanying drawings.

[0015] The forward / backward direction is the direction of travel of the tractor 1 when traveling straight, with the front side of the traveling direction defined as "front" and the rear side defined as "rear." The traveling direction of the tractor 1 is the direction from the operator's seat 8 (described later) toward the steering wheel 9 when traveling straight.

[0016] The left-right direction is a direction that is horizontally perpendicular to the front-rear direction. In other words, when the operator of the tractor 1 is seated in the operator's seat 8 and facing forward, the left-hand side is the "left" side and the right-hand side is the "right" side.

[0017] The up-down direction is a direction parallel to the vertical direction. The front-rear direction, left-right direction, and up-down direction are perpendicular to each other. Note that each direction is defined for the convenience of explanation, and the present invention is not limited by these directions. In the following, the tractor 1 may also be referred to as the "machine body."

[0018] Furthermore, the present invention is not limited to the following embodiments.

[0019] 1 to 5, the tractor 1 is an agricultural tractor that travels by itself to perform work in a field, etc. The tractor 1 not only performs predetermined work while being driven by an operator (operator) while traveling within the field, but also performs predetermined work while automatically traveling within the field through control of each part by a control system centered on a control device 20, which will be described later.

[0020] The tractor 1 is equipped with a working machine W at the rear of a traveling body 2, which can be raised and lowered by a lifting device 12.

[0021] The traveling vehicle body 2 includes a vehicle body frame 3, front wheels 4, rear wheels 5, a bonnet 6, an engine E, a steering section 7, and a transmission case 10.

[0022] The body frame 3 and the transmission case 10 form the main frame of the traveling body 2.

[0023] The front wheels 4 are a pair of left and right wheels, and are mainly used for steering (steered wheels). The rear wheels 5 are a pair of left and right wheels, and are mainly used for driving (drive wheels).

[0024] The tractor 1 may be configured to be switchable between two-wheel drive (2WD) in which the rear wheels 5 are driven, and four-wheel drive (4WD) in which both the front wheels 4 and the rear wheels 5 are driven. In this case, both the front wheels 4 and the rear wheels 5 are driven wheels. The traveling body 2 may be equipped with a crawler device instead of wheels (front wheels 4 and rear wheels 5). In this case, the traveling crawler is the driven wheel.

[0025] The hood 6 is provided at the front of the vehicle body 2 so as to be able to be opened and closed freely. The hood 6 can be rotated (opened and closed) in the vertical direction with the rear part as the rotation center. When closed, the hood 6 covers the engine E mounted on the body frame 3.

[0026] The engine E is a drive source for the tractor 1 and is a heat engine such as a diesel engine or a gasoline engine.

[0027] The control unit 7 is provided on the upper part of the traveling vehicle body 2 and includes a driver's seat 8 and a steering wheel 9. The control unit 7 may be formed by being covered by a cabin 7a provided on the upper part of the traveling vehicle body 2.

[0028] The driver's seat 8 is a seat for the driver. The steering wheel 9 is operated by the driver when steering the front wheels 4, which are steered wheels. The control unit 7 is provided in front of the steering wheel 9 with a meter panel 11 (display unit) that displays various information.

[0029] The control unit 7 also includes various operation levers such as a forward / reverse lever, an accelerator lever, a main speed change lever, and an auxiliary speed change lever, as well as various operation pedals such as a clutch pedal 18, a brake pedal, and an accelerator pedal 19.

[0030] The transmission case 10 houses a transmission (speed change mechanism). The transmission appropriately reduces the speed of power (rotational power) transmitted from the engine E and transmits it to the rear wheels 5, which are drive wheels, and the PTO shaft.

[0031] A work implement W that performs work in the field is connected to the rear of the traveling body 2, and a PTO shaft that transmits power to drive the work implement W protrudes rearward from the transmission case 10. The PTO shaft transmits rotational power that has been appropriately reduced by the transmission to the work implement W that is attached to at least the rear of the traveling body 2.

[0032] In addition, a lifting device 12 that raises and lowers the work implement W is provided at the rear of the traveling body 2. The lifting device 12 raises the work implement W to move it to a non-working position. The non-working position is a position where the work implement W is raised when, for example, the traveling body 2 moves backward or turns. In addition, the lifting device 12 lowers the work implement W to move it to a ground work position. The lifting device 12 includes a hydraulic lifting cylinder 121, a lift arm 122, a lift rod 123, a lower link 124, and a top link 125.

[0033] When hydraulic oil is supplied to the lifting cylinder 121, the lift arm 122 rotates around the axis AX, which serves as the pivot point, to raise the work equipment W, and when hydraulic oil is discharged from the lifting cylinder 121, the lift arm 122 rotates around the axis AX to lower the work equipment W.

[0034] A lift arm sensor 26 is provided at the base of the lift arm 122 (near the axis AX) as a lifting device sensor for detecting the rotation angle of the lift arm 122.

[0035] The work implement W is a machine that performs work in a farm field. In the illustrated example, the work implement W is a rotary tiller that performs tilling work in the farm field.

[0036] The rotary tiller tills the field (soil) by rotating the tiller tines 27 using power transmitted from the PTO shaft. The tiller tines 27 are covered above, behind, and on the left and right sides by rotary covers 27a.

[0037] The height of the work implement W is calculated based on the detection results of the lift arm sensor 26 and a comparison of the height of the work implement W obtained by the work implement positioning device 31 attached to the work implement W and the height of the traveling vehicle body 2 obtained by the vehicle body positioning device 30 attached to the traveling vehicle body 2.

[0038] The vehicle body positioning device 30 and the work equipment positioning device 31 are, for example, GNSS antennas that can receive radio waves from navigation satellites S orbiting in the sky to perform positioning and timing. They can also calculate the moving speed from the history of positioning results and the Doppler effect of radio waves.

[0039] The information acquired by the work implement positioning device 31 is sent to the control device 20 via a harness 32, which is a wiring for transmitting information. The terminal at the tip of the harness 32 is detachable from the work implement positioning device 31, and when the work implement W is attached to the suspension device 50 of the tractor 1, the terminal at the tip of the harness 32 is inserted into the work implement positioning device 31, and when the work implement W is removed from the suspension device 50 of the tractor 1, the terminal at the tip of the harness 32 is removed from the work implement positioning device 31.

[0040] The work implement positioning device 31 is provided at the upper end of a positioning device bracket 38 whose base is fixed to the rear of a slide hitch 37 that is provided on a frame 36 of the work implement W so as to be adjustable up and down.

[0041] The slide hitch 37 is composed of a base frame 37b whose base is pivoted to the frame 36 by a pivot shaft 37a, and a tip frame 37c fitted into the base frame 37b and slidable in the front-rear direction.

[0042] The base frame 37b is configured by connecting the tip ends of left and right cylinders 37d with left and right connecting pipes 37e, and the left and right central parts of the left and right connecting pipes 37e are connected to a screw-type vertical position adjustment mechanism 39.

[0043] The tip frame 37c is configured by connecting the tip portions of left and right pipe members 37f, which are fitted into left and right cylinders 37d of the base frame 37b and can slide freely in the front-rear direction, with a toolbar 37g that is long in the left-right direction.

[0044] The left and right cylinders 37d of the base frame 37b of the slide hitch 37 and the left and right pipe members 37f of the tip frame 37c have through holes 37h at the same pitch, and the left and right pipe members 37f fitted into the left and right cylinders 37d of the base frame 37b are slid forward and backward and a fixing pin 37i is inserted into any of the through holes 37h to fix them, thereby adjusting the forward and backward length of the slide hitch 37.

[0045] The slide hitch 37 is used to attach work equipment such as a ridger or pesticide sprayer to a toolbar 37g that is long in the left-right direction and is provided at the rear end, and in this embodiment, the base of the positioning device bracket 38 is fixed to the center of the toolbar 37g by a connecting pin 40.

[0046] The positioning device bracket 38 is configured with an arm 38b extending forward from a U-shaped mounting portion 38a provided at the base that is attached to the tool bar 37g, and a vertical support stay 38c provided at the front end of the arm 38b, and the work machine positioning device 31 is provided at the upper end of the support stay 38c.

[0047] Therefore, since the work implement positioning device 31 is attached to the toolbar 37g of the existing slide hitch 37, which can be freely adjusted in the forward and backward directions, the forward and backward directions can be easily changed.

[0048] The upper part of the vertical position adjustment mechanism 39 is rotatably supported on the frame 36 by a left-right support shaft 39a, and the lower part is connected to a midpoint between the front and rear of the pivot shaft 37a of the base (front end) of the slide hitch 37.

[0049] When the operating handle 39b provided on the top of the vertical position adjustment mechanism 39 is rotated, the screw shaft 39c rotates and the cylindrical body 39d, which has a screw groove that screws into the screw of the screw shaft 39c, moves up and down (extends and contracts), and the slide hitch 37 moves up and down around the pivot shaft 37a at the base, allowing the vertical position of the work equipment positioning device 31 to be adjusted.

[0050] In other words, the vertical position of the work equipment positioning device 31 can be adjusted using a vertical position adjustment mechanism 39 that changes the vertical position of a conventional (existing) slide hitch 37 for adjusting the vertical position of work equipment such as a ridger or pesticide sprayer attached to the slide hitch 37.

[0051] Therefore, in the past, it was necessary to change the reference height of the work implement positioning device 31 using a setting device provided on the control unit 7, but in the embodiment of the present invention, by providing the work implement positioning device 31 on the slide hitch 37, the vertical position of the work implement positioning device 31 can be easily adjusted using the conventional vertical position adjustment mechanism 39 that changes the vertical position of the slide hitch 37.

[0052] In addition, the positioning device bracket 38 that attaches the work implement positioning device 31 to the slide hitch 37 has a configuration in which an arm 38b extending forward from a U-shaped attachment portion 38a provided at the base that is attached to the toolbar 37g of the slide hitch 37 has an arm 38b that extends forward of the machine body and has an up-and-down support stay 38c at the front end thereof.As the work implement positioning device 31 is positioned forward of the toolbar 37g, which is the attachment portion of the slide hitch 37, it is possible to prevent it from being hit by mud that is kicked up by the rotation of the tillage tines 27, and it is also positioned forward and away from the rear end of the slide hitch 37 (positioned close to the front of the slide hitch 37), so it is less susceptible to the effects of vibrations generated by the rotation of the tillage tines 27 during tillage work.

[0053] Furthermore, since the work implement positioning device 31 is attached to the existing slide hitch 37, it is highly versatile and can be used regardless of the method for attaching the work implement W to the tractor 1.

[0054] In addition, the work implement positioning device 31 is positioned above the rotary cover 27a that covers the tiller tines 27 of the rotary tiller, which is the work implement W, so it is less susceptible to dirt even if the rotary tiller becomes dirty with mud or the like.

[0055] Furthermore, since the work implement positioning device 31 is disposed in the left-right center of the rotary tiller, which is the work implement W, it is less susceptible to left-right shaking when the rotary tiller tilts left or right.

[0056] The work machine W is attached by engaging an upper locking pin 36a provided at the front upper end of the frame 36 with an upper hook 50a that opens upward of the suspension device 50 provided at the rear end of the lifting device 12, engaging left and right lower locking pins 36b provided at the front lower part of the frame 36 with left and right lower hooks 50b that open upward and are provided at the bottom of the suspension device 50, and locking the left and right lower locking pins 36b from above with left and right locking hooks 51a that open downward of the locking mechanism 51.

[0057] The lock mechanism 51 can be freely changed in position between a locked state in which the left and right lower locking pins 36b are engaged and an unlocked state in which the left and right lower locking pins 36b are released by rotating the left and right locking hooks 51a with the operating lever 51b.

[0058] An unlock detection sensor is provided on the suspension device 50 side of the tractor 1 to detect the unlocked state of the locking mechanism 51, and when the unlock detection sensor detects that the locking mechanism 51 is unlocked and that the harness 32 connecting the work implement positioning device 31 and the control device 20 is connected (when the control device 20 receives an input signal from the work implement positioning device 31), an alarm device such as an audio alarm or monitor provided in the operating unit 7 notifies the user that the harness 32 is still connected even though the locking mechanism 51 has been unlocked.

[0059] Therefore, by providing an unlock detection sensor on the suspension device 50 side of the tractor 1 that detects the unlocked state of the locking mechanism 51, there is no need to detach the wiring connecting the unlock detection sensor to the control device 20 when attaching or detaching the work implement W to or from the suspension device 50, which improves workability.

[0060] Furthermore, by notifying that the harness 32 connecting the work implement positioning device 31 and the control device 20 is connected when the locking mechanism 51 is in the unlocked state, damage due to forgetting to unplug the harness 32 when removing the work implement W from the suspension device 50 of the tractor 1 can be prevented.

[0061] The tractor 1 also includes a control device 20. The control device 20 controls the engine E and also controls the traveling speed of the traveling vehicle body 2. The control device 20 also controls the lifting and lowering of the work implement W.

[0062] As shown in Figure 1, the tractor 1 calculates the position H of the work implement W relative to the traveling body 2 from the position H1 of the traveling body 2 obtained by the vehicle body positioning device 30 and the position H2 of the work implement W obtained by the work implement positioning device 31.

[0063] In the example shown in FIG. 1, the work machine positioning device 31 is raised and lowered so as to be located at a predetermined position H relative to the vehicle body positioning device 30.

[0064] Furthermore, the control device 20 calculates the height of the field from the position H2 of the work implement W because the position H1 of the traveling body 2 is a fixed value depending on the body.

[0065] The control device 20 then creates a height map of the field from the height of the field calculated from the position H2 of the work implement W and the positioning information from the vehicle body positioning device 30.

[0066] Then, from the height map of the field, information on the levelness of the field is generated, a decision is made as to whether mounding of the field is necessary using a loader or the like, and the height map and the areas where mounding of the field is necessary are displayed on the display device (liquid crystal monitor) of the control unit 7.

[0067] Furthermore, when automatically raising or lowering the work implement W to a specified height, the control device 20 uses the detection status of the lift arm sensor 26 or the vehicle body positioning device 30 and the work implement positioning device 31. Specifically, when the detection status of the lift arm sensor 26 or the vehicle body positioning device 30 and the work implement positioning device 31 is in a specific state, the control device 20 determines that the lifted position of the work implement W is at a specified height. This point will be explained using FIG. 1.

[0068] 1 shows a case where the height of the traveling vehicle body 2 is H1 and the lifted position of the rotary tiller, which is the work implement W, is at height H2. When the work implement W is a rotary tiller, the control device 20 detects the situation shown in FIG. 1 as a tilling operation state and determines that the work implement W is at a specified height. For example, if the position H of the work implement W relative to the traveling vehicle body 2 is within a specified range based on the difference between the height H1 of the traveling vehicle body 2 obtained from the vehicle body positioning device 30 and the height H2 of the work implement W obtained from the work implement positioning device 31, or if the angle of the lift arm 122 is within a specified range, the control device 20 determines that the work implement W is at a specified height and is in a tilling operation state.

[0069] In other words, the control device 20 can raise and lower the work implement W to an appropriate position by determining that the lifting position of the work implement W is at a specified height from the position H of the work implement W relative to the traveling vehicle body 2 or the rotation angle D of the lift arm 122.

[0070] Furthermore, in FIG. 1, the working machine W is a rotary cultivator, but the working machine W may be, for example, a harrow (a soil harrow), a broadcaster (a fertilizer applicator), a towing working machine, or the like.

[0071] Furthermore, the specific situation in which the control device 20 determines that the lifted position of the work implement W is at a specified height may differ depending on the type of work implement W.

[0072] Therefore, by using the vehicle body positioning device 30 and the work implement positioning device 31, tillage depth control that is less affected by the posture of the tractor 1 or the unevenness of the field becomes possible.

[0073] The control device 20 also controls the lifting speed when automatically lifting and lowering the work implement W. Specifically, the control device 20 slows the lifting speed of the automatic lifting and lowering when the tractor 1 is traveling on roads (in road mode) compared to the lifting speed when traveling in a field (in field mode). This improves safety when traveling on roads where there are more obstacles and pedestrians than in a field.

[0074] Further advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. [Explanation of symbols]

[0075] 2 Running vehicle 12 Lifting device 20 Control device 31 Positioning device (work equipment positioning device) 32 Wiring (harness) 37 Slide hitch 38 Positioning device bracket 38a Mounting part 38b Arm 38c support stay 39 Vertical position adjustment mechanism 50 Suspension system 51 Locking mechanism W Work Machine

Claims

1. A work vehicle having a working implement (W) mounted on a traveling body (2) so as to be freely raised and lowered by a lifting device (12), characterized in that a positioning device (31) for measuring the vertical position of the working implement (W) is provided on a slide hitch (37) whose vertical position can be freely changed by a vertical position adjustment mechanism (39) of the working implement (W), and a control device (20) for controlling the lifting device (12) so that the working implement (W) reaches a predetermined height based on height position information obtained from the positioning device (31).

2. 2. The work vehicle according to claim 1, wherein the positioning device bracket (38) for mounting the positioning device (31) to the slide hitch (37) is composed of a mounting portion (38a) for mounting to the slide hitch (37), an arm (38b) extending forward from the mounting portion (38a), and a support stay (38c) for mounting the positioning device (31) provided at the tip of the arm (38b).

3. 3. The work vehicle according to claim 1 or 2, characterized in that the suspension device (50) is provided with an unlock detection sensor that detects the unlocked state of a locking mechanism (51) that locks the connection of a work machine (W) attached to the suspension device (50) of the lifting device (12), and when the unlock detection sensor detects the unlocked state, it issues an alert when it detects that a wiring (32) connecting the positioning device (31) and the control device (20) is connected.

Images