Work vehicles

Abstract

To provide a work vehicle that can prevent malfunctions caused by rapid increases in engine speed. [Solution] A work vehicle according to one embodiment comprises a vehicle body, an engine mounted on the vehicle body, a PTO shaft that outputs engine power to the outside, a work machine to which power from the PTO shaft is transmitted, a control device that can control the engine speed at a set constant rotational speed, and an increase time setting means that can set the time for the engine speed to increase until it reaches a constant rotational speed to a first time.

Description

Technical Field

[0001] The present invention relates to a work vehicle.

Background Art

[0002] Conventionally, a vehicle engine control system including an engine control unit that controls the engine speed based on the engine speed stored in a memory unit has been known (see, for example, Patent Document 1). The engine control unit includes a switch having a first operation position that creates a first switching state and a second operation position that creates a second switching state.

[0003] In the engine control unit, when the first switching state or the second switching state continues for a predetermined time or more, the engine speed corresponding to the current accelerator position is stored in the memory unit. Further, when the first switching state continues for less than the predetermined time, the engine speed is adjusted based on the engine speed read from the memory unit. Further, when the second switching state continues for less than the predetermined time, the engine speed stored in the memory unit is displayed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the above prior art, since the engine speed increase time is constant, problems such as belt slip of the work machine due to the rapid increase in the engine speed have occurred depending on the work machine.

[0006] The present invention has been made in view of the above, and an object thereof is to provide a work vehicle capable of preventing problems caused by a rapid increase in the engine speed. [Means for solving the problem]

[0007] To solve the above-mentioned problems and achieve the objective, a riding lawnmower (1) according to one embodiment comprises a vehicle body (2), an engine (21) mounted on the vehicle body (2), a PTO shaft (23) that outputs power from the engine (21) to the outside, a work implement (5) to which power from the PTO shaft (23) is transmitted, a control device (10) that can control the engine speed at a set constant rotational speed, and an increase time setting means (12) that can set the time it takes for the engine speed to increase until it reaches a constant rotational speed to a first time (t1). [Effects of the Invention]

[0008] According to the riding lawnmower of this embodiment, it is possible to prevent malfunctions caused by a rapid increase in engine speed. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a side view showing the overall configuration of a work vehicle according to this embodiment. [Figure 2] Figure 2 is a plan view showing the work machine according to the embodiment. [Figure 3] Figure 3 is a block diagram showing an example of a control system in a work vehicle according to this embodiment. [Figure 4] Figure 4 illustrates the time it takes for the engine speed to increase. [Figure 5] Figure 5 illustrates the PTO clutch engagement time. [Figure 6] Figure 6 illustrates the operating conditions for the PTO interlock. [Figure 7] Figure 7 illustrates the display of suit quantity using a display device. [Modes for carrying out the invention]

[0010] The embodiments of the work vehicle disclosed herein will be described in detail below with reference to the attached drawings. However, the present invention is not limited to the embodiments described below.

[0011] First, the overall configuration of the work vehicle according to the embodiment will be described with reference to Figure 1. Figure 1 is a side view showing the overall configuration of the work vehicle according to the embodiment. Figure 2 is a top view showing the work machine according to the embodiment. In this embodiment, the riding lawnmower 1 will be described first as an example of a work vehicle.

[0012] Furthermore, in this embodiment, the forward and backward direction refers to the direction of travel when the riding lawnmower 1 is moving straight, with the front side of the direction of travel defined as "front" and the rear side as "rear".

[0013] The left-right direction is the direction perpendicular to the front-back direction. In the following, left and right are defined with respect to the "front" side. That is, with the operator (worker) of the riding lawnmower 1 facing forward in the control unit 6 described later, the left hand side is "left" and the right hand side is "right".

[0014] The vertical direction is the direction parallel to the vertical direction. The front-back direction, left-right direction, and vertical direction are orthogonal to each other. Note that these directions are defined for the sake of explanation, and the present invention is not limited by these directions. Also, in this embodiment, the riding lawnmower 1 may be referred to as the "machine body".

[0015] As shown in Figure 1, the riding lawnmower 1 comprises a vehicle body 2, a pair of front wheels 3, a pair of rear wheels 4, a mowing device 5, an operating unit 6, a transmission case 7, and a floor 8. An engine fuel tank 9 is mounted beneath the floor 8. The mowing device 5 has a mower deck 50 (see Figure 2) with belt-driven blades (not shown) mounted on its inner underside. The riding lawnmower 1 is a so-called mid-mount type riding lawnmower in which the mowing device 5 is mounted on the vehicle body 2 between the front wheels 3 and the rear wheels 4. The mower deck 50 is suspended from the vehicle body 2 via suspension arms 51 and 52. Note that the mowing device 5 is just one example of a work implement, and other belt-driven work implements may be used, for example.

[0016] As shown in FIG. 2, the mower deck 50 has a case 53 and a connecting portion 56. The mower deck 50 cuts grass, turf, etc., and discharges the cut grass to the outside.

[0017] The case 53 is a cover member that covers the blade. The case 53 is provided with an eaves portion 54 at a discharge port for discharging cut grass to the right side in the left-right direction. The case 53 has a plurality of wheels 55, and is movable in the front-rear direction by the plurality of wheels 55.

[0018] The connecting portion 56 is connected to a PTO shaft 23 (see FIG. 1) located below the rear portion of the traveling vehicle body 2, and power is transmitted from the PTO shaft 23. The connecting portion 56 is connected to a pulley 58 around which a belt 57 is wound, and drives the blade connected to the pulley 58 to rotate.

[0019] Next, the control system of the work vehicle according to the embodiment will be described with reference to FIG. 3. FIG. 3 is a block diagram showing an example of the control system in the work vehicle according to the embodiment.

[0020] As shown in FIG. 3, an accelerator memory switch 11, a volume switch 12 which is an example of an ascending time setting means, a PTO connection switch 13, a connection mode changeover switch 14, an accelerator lever 15, and a work mode changeover switch 16 are connected to the control device 10. The control device 10 can acquire signals from the accelerator memory switch 11, the volume switch 12, the PTO connection switch 13, the connection mode changeover switch 14, the accelerator lever 15, and the work mode changeover switch 16, and control the operations of each part of the machine body based on the acquired signals.

[0021] The accelerator memory switch 11 is an operating device that allows the engine speed to be changed to a preset speed by switching it on. The volume switch 12 is an operating device that allows the time it takes for the engine speed to increase to a constant speed to be set to any first time. For example, the volume switch 12 may be a dial type that allows the operator to continuously set the value by turning the dial left or right. The PTO connection switch 13 is an operating device that instructs the on / off operation to connect and disconnect the power transmitted to the PTO shaft 23.

[0022] The connection mode selector switch 14 is an operating device for instructing the switching of the connection mode of the PTO clutch 22, which will be described later. The accelerator lever 15 is an operating device for instructing an increase in engine speed. The work mode selector switch 16 is an operating device for instructing the switching of the work mode.

[0023] Furthermore, the control device 10 can drive and control various parts of the riding lawnmower 1, such as the engine 21, PTO clutch 22, and various actuators 24. The PTO clutch 22 performs on / off operations to connect and disconnect the power transmitted to the PTO shaft 23. When the accelerator memory switch 11 is pressed while the engine 21 is idling, the control device 10 can perform constant engine speed control at a preset constant rotational speed.

[0024] Furthermore, the control device 10 can display images on the display device 61. For example, the display device 61 is provided on the meter panel located in front of the driver's unit 6.

[0025] Next, the time it takes for the engine speed to increase and the engagement time of the PTO clutch 22 in the riding lawnmower 1 according to the embodiment will be described with reference to Figures 4 and 5. Figure 4 is a diagram illustrating the time it takes for the engine speed to increase. Figure 5 is a diagram illustrating the engagement time of the PTO clutch 22. In Figure 4, the horizontal axis represents time, and the vertical axis represents engine speed. In Figure 5, the horizontal axis represents time, and the vertical axis represents the pressure of the hydraulic fluid that operates the PTO clutch 22.

[0026] The riding lawnmower 1 is configured such that, for example, when the accelerator memory switch 11 is pressed while the engine 21 is idling, the time it takes for the engine speed to reach a constant speed N can be arbitrarily set. Specifically, as described above, the riding lawnmower 1 is provided with a volume switch 12 in addition to the accelerator memory switch 11, and the operator can easily change the time it takes for the engine speed to increase using the volume switch 12. Therefore, the riding lawnmower 1 is easier to use because the time it takes for the engine speed to increase (speed increase rate) can be freely set by physically operating the volume switch 12.

[0027] For example, the control device 10 sets the time to increase the engine speed to a first time t1 based on the operator's operation of the volume switch 12. When the operator presses the accelerator memory switch 11, the control device 10 increases the engine speed at a constant rate of increase during the first time t1, as shown in Figure 4. After the engine speed reaches a constant speed N, the control device 10 controls the engine speed so that it remains constant at the constant speed N.

[0028] Conventionally, because the time it takes for the engine speed to increase is constant (only the setting of constant speed N is possible), the engine speed may increase too quickly depending on the work equipment (lawn mowing device 5 in this embodiment), causing problems such as belt slippage of the mower deck 50. With the riding lawn mower 1 of the present invention, by setting the engine speed increase time according to the mower deck 50, it is possible to prevent belt slippage caused by a rapid increase in engine speed.

[0029] The riding lawnmower 1 may have a setting screen on its display device 61, allowing the engine speed increase time to be adjusted via the setting screen. In other words, the setting screen may be configured as a touch panel. The means for setting the increase time may be an operation screen displayed on the setting screen. This configuration allows the riding lawnmower 1 to be configured so that settings that are not frequently changed are set on the meter panel, thereby reducing the number of switches and improving ease of use.

[0030] The riding lawnmower 1 may be equipped with multiple accelerator memory switches 11, and the engine speed increase time may be set individually for each accelerator memory switch 11. This eliminates the need for the riding lawnmower 1 to change the engine speed increase time setting for each of the multiple mowing devices 5, thereby improving work efficiency.

[0031] The control device 10 may also have a function to switch the connection mode of the PTO clutch 22. Specifically, the control device 10 may have a "standard mode" and a "slow mode" in which the PTO clutch 22 is connected for a longer period than in the "standard mode".

[0032] For example, as shown in Figure 5, in "standard mode," the connection time of the PTO clutch 22 is set to the third time t3. In "slow mode," the connection time of the PTO clutch 22 is set to the fourth time t4, which is longer than the third time t3. The control device 10 sets the connection mode of the PTO clutch 22 according to the work machine to which it is attached. Note that the third time t3 and the fourth time t4 can be changed as preset values.

[0033] For example, the control device 10 sets the connection mode of the PTO clutch 22 based on the operator's operation of the connection mode selector switch 14. When the "standard mode" is set, the control device 10 increases the hydraulic fluid pressure during the third time t3 as shown in Figure 4 when the operator presses the PTO connection switch 13 (see pressure transition Lc). When the "slow mode" is set, the control device 10 increases the hydraulic fluid pressure during the fourth time t4 when the operator presses the PTO connection switch 13 (see pressure transition Ld). The PTO clutch 22 enters an engaged state, connecting the power transmitted to the PTO shaft 23 when the hydraulic fluid pressure reaches pressure P.

[0034] The vehicle body 2 has a piston (not shown) that actsuates the PTO clutch 22 and an oil chamber (not shown) that moves the piston. The hydraulic fluid pressure is constant during the initial time required to fill the oil chamber with hydraulic fluid. After the initial time, the control device 10 controls the hydraulic fluid pressure by lowering it and then raising it to pressure P.

[0035] The control device 10 may change the engine speed increase time according to the connection mode of the PTO clutch 22. For example, when the connection mode of the PTO clutch 22 is "standard mode", the control device 10 automatically sets the engine speed increase time to be shorter than when the connection mode of the PTO clutch 22 is "slow mode". Also, when the connection mode of the PTO clutch 22 is "slow mode", the control device 10 automatically sets the engine speed increase time to be longer than when the connection mode of the PTO clutch 22 is "standard mode".

[0036] With the riding lawnmower 1 configured in this way, the time it takes for the engine speed to increase is automatically increased in response to the mowing device 5, which engages the PTO slowly. As a result, the riding lawnmower 1 automatically adjusts the time it takes for the engine speed to increase in response to the mowing device 5, improving operability.

[0037] Furthermore, the control device 10 may set the engine speed increase time to the first time t1 when the PTO clutch 22 connection mode is "standard mode". The control device 10 may set the engine speed increase time to the second time t2, which is longer than the first time t1, when the PTO clutch 22 connection mode is "slow mode". The first time t1 is longer than the third time t3. The second time t2 is longer than the fourth time t4.

[0038] For example, when the connection mode of the PTO clutch 22 is "standard mode," the operator presses the PTO connection switch 13 and the accelerator memory switch 11 in that order. In this case, the control device 10 puts the PTO clutch 22 into the engaged state at the third time t3 and sets the engine speed to the constant speed N at the first time t1.

[0039] Furthermore, when the PTO clutch 22 is in "slow mode," the operator presses the PTO connection switch 13 and the accelerator memory switch 11 in that order. In this case, the control device 10 engages the PTO clutch 22 at the fourth time t4 and sets the engine speed to the constant speed N at the second time t2.

[0040] In this configuration, the riding lawnmower 1 has a longer engine speed increase time than the PTO clutch 22 engagement time. In other words, the engine speed reaches a constant speed N after the PTO clutch 22 is engaged. This makes it easier for the operator to recognize the timing to start work, as they can begin work when the engine speed reaches a constant speed N based on the sound of the engine speed increasing.

[0041] In this embodiment, the accelerator memory switch 11 and the PTO connection switch 13 have been described as separate operating devices, but this is not particularly limited, and the accelerator memory switch 11 and the PTO connection switch 13 may be a single operating device. If the accelerator memory switch 11 and the PTO connection switch 13 are a single operating device, the control device 10 may simultaneously start increasing the engine speed and supplying hydraulic fluid for connecting the PTO clutch 22 when the operating device is operated by an operator.

[0042] Furthermore, if the riding lawnmower 1 is configured to have a long engine speed increase time, the engine speed increase time (rate of increase) when the accelerator lever 15 is operated may also be configured to be similarly long. By matching the engine speed increase time (rate of increase) when the accelerator memory switch 11 and the accelerator lever 15 are operated, the riding lawnmower 1 can prevent belt slippage of the implement when the accelerator lever 15 is operated.

[0043] Furthermore, the riding lawnmower 1 may be equipped with a work mode selector switch 16 that allows switching between multiple work modes, and the time for increasing the engine speed may be set for each work mode. Since the riding lawnmower 1 allows setting the time for increasing the engine speed according to the work mode, operability is improved.

[0044] Next, the PTO interlock according to the embodiment will be described with reference to Figure 6. Figure 6 is a diagram illustrating the operating conditions of the PTO interlock. In the following description, a tractor will be used as an example of the work vehicle.

[0045] The 2025 safety inspection standards for tractors require a PTO interlock. A PTO interlock is a mechanism that, if the driver leaves the seat while power is connected to the PTO shaft while the vehicle body 2 is stopped, will cut off power to the PTO shaft or shut off the power source within 7 seconds of the driver leaving the seat. In small tractors that do not have a PTO clutch, it is not possible to cut off power to the PTO shaft, so the power source is shut off (for example, the engine 21 is shut off), which reduces work efficiency.

[0046] For example, "driving" refers to a situation where the vehicle is equipped with forward / reverse levers and gear shift levers (main and sub-shift), both levers are in the "driving position (other than the neutral position)", the parking brake is not applied, and the vehicle is detected to be in motion by a vehicle speed sensor or similar device. For example, "stopped" refers to a situation where either the forward / reverse lever or the gear shift lever (main or sub-shift) is in the "neutral position (other than the driving position)", or the parking brake is applied, and the vehicle is detected to be stopped by a vehicle speed sensor or similar device.

[0047] The vehicle body 2 is equipped with a seat switch in the driver's compartment 6 to detect when a driver is seated. The tractor is equipped with a neutral detection sensor on the forward / reverse lever to detect the neutral position of the forward / reverse lever. The tractor is equipped with a neutral detection sensor on the auxiliary transmission lever to detect the neutral position of the auxiliary transmission lever. The tractor is equipped with a detection sensor on the PTO lever to detect the ON / OFF position of the PTO lever.

[0048] As shown in the first clutch cutoff in Figure 6, the control device 10 does not activate the PTO interlock regardless of the lever position when the driver is seated (seat switch detected).

[0049] When the PTO lever is in the OFF position, the control device 10 does not activate the PTO interlock, regardless of whether the driver is seated or unseated, or the position of other levers (forward / reverse lever position, sub-transmission lever position).

[0050] The control device 10 determines that the vehicle is "driving" if both the forward / reverse lever and the auxiliary transmission lever are in a position other than neutral, and therefore does not activate the PTO interlock.

[0051] When the control device 10 detects that the driver has left the vehicle while the PTO lever is in the ON position and either the forward / reverse lever or the auxiliary transmission lever is in the neutral position, it activates the PTO interlock.

[0052] The vehicle body 2 is equipped with an actuator on the clutch pedal arm. The actuator does not operate during normal clutch pedal operation. The control device 10 activates the actuator when the PTO interlock is activated, cutting off the clutch. The clutch cutoff cuts off the power from the engine 21, stopping the drive of the PTO shaft. The control device 10 also displays the clutch cutoff state by the actuator on the instrument panel.

[0053] The control device 10 returns the actuator to its normal state when the operator depresses the clutch pedal and presses the switch at the pedal pivot point. This makes it easier for the operator to move on to the next action (driving) because the clutch pedal is depressed under the release condition. The switch at the pedal pivot point also serves as the engine start switch.

[0054] The vehicle body 2 is equipped with a detection sensor on the parking lever to detect the ON / OFF position of the parking lever. The parking lever is of the pedal lock type. The pedal lock type is a system in which the parking is engaged by the operator pressing the brake pedal and lowering the parking lever.

[0055] The conditions for clutch cutoff described above may be supplemented with detection of the ON / OFF position of the parking lever. As shown in the second clutch cutoff in Figure 6, the control device 10 activates the clutch cutoff when the vehicle is drivable, regardless of the driver's seating position and the position of the PTO lever, and when both the forward / reverse lever and the sub-transmission lever are in a position other than neutral, and the parking lever is ON. This helps to prevent brake wear and other issues.

[0056] The vehicle body 2 may be equipped with a hand-operated parking lever that operates the brakes independently of the brake pedal linkage. An actuator may be provided at the pivot point of the parking lever, so that the parking brake is automatically engaged when the PTO interlock is activated.

[0057] Next, the suit quantity display by the display device 61 according to this embodiment will be described with reference to Figure 7. Figure 7 is a diagram illustrating the suit quantity display by the display device 61.

[0058] In a tractor equipped with an engine 21 having a DPF (Diesel Particulate Filter), the vehicle body 2 may be equipped with a segment-type display device 61 (liquid crystal panel) on the meter panel 60. It is provided with 7-segment display for numerical and character displays, and bar displays for water temperature and fuel gauge. When displaying soot, "Soot" is displayed on the 7-segment section 62, and the fuel gauge section 63 displays the soot amount. The vehicle body 2 is provided with a display switching switch, allowing switching between fuel gauge display and soot amount display.

[0059] Traditionally, tractors have been equipped with LCD panels, but some lack a suit display function. Therefore, if such tractors are used under conditions where automatic regeneration is not functioning, they may require a sudden stop and manual regeneration, potentially interrupting work.

[0060] According to the tractor of this invention, by making it possible to check the amount of soot, the operator can select working conditions (full throttle operation) that make automatic regeneration more likely to occur when the amount of soot increases. As a result, automatic regeneration is performed before manual regeneration becomes necessary, preventing interruptions to work.

[0061] The tractor may be configured to flash the entire soot amount indicator during regeneration. By displaying a special indicator for regeneration, the tractor makes it easier to understand that regeneration is in progress. The tractor may also be configured to change the flashing cycle according to the soot amount. For example, the flashing cycle could be slowed down when the soot amount is large and sped up as the soot amount decreases. This provides an estimate of the remaining regeneration time, allowing the operator to plan the next task based on this estimate.

[0062] As described above, the riding lawnmower 1 according to this embodiment comprises a vehicle body 2, an engine 21 mounted on the vehicle body 2, a PTO shaft 23 that outputs power from the engine 21 to the outside, a lawnmower 5 to which power from the PTO shaft 23 is transmitted, a control device 10 that can control the engine speed at a set constant rotational speed N, and a volume switch 12 that can set the time it takes for the engine speed to increase until it reaches the constant rotational speed N to a first time t1. With the riding lawnmower 1 configured in this way, the time it takes for the engine speed to increase can be adjusted according to the lawnmower 5 using the volume switch 12. Therefore, problems caused by a rapid increase in engine speed can be prevented.

[0063] Furthermore, the riding lawnmower 1 is equipped with a PTO clutch 22 that performs on / off operations to connect and disconnect power transmitted to the PTO shaft 23. The control device 10 can change the connection time, which is the time from when the control to connect the PTO clutch 22 (supply of hydraulic fluid as described above) is started until the PTO clutch 22 is connected. The control device 10 has a standard mode in which the connection time of the PTO clutch 22 is a third time t3, and a slow mode in which the connection time of the PTO clutch 22 is a fourth time t4, which is longer than the third time t3, and changes the engine speed increase time according to the PTO clutch 22 connection time. According to the riding lawnmower 1 of the present invention, the engine speed increase time can be automatically changed to be longer for the mowing device 5 that connects the PTO slowly. As a result, the engine speed increase time is automatically changed to be longer according to the mowing device 5, so problems caused by a rapid increase in engine speed can be prevented.

[0064] Furthermore, the control device 10 sets the time it takes for the engine speed to increase to a first time t1 when in standard mode, and sets the time it takes for the engine speed to increase to a second time t2 which is longer than the first time t1 when in slow mode, with the first time t1 being longer than the third time t3, and the second time t2 being longer than the fourth time t4. According to the riding lawnmower 1 of the present invention, the time it takes for the engine speed to increase is longer than the time the PTO clutch 22 is engaged. As a result, the operator can start working at the moment when the engine speed reaches a constant speed N based on the sound of the engine speed increasing, making it easier to recognize when to start working.

[0065] Further effects and modifications can be readily derived by those skilled in the art. Therefore, broader aspects of the present invention are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents. [Explanation of symbols]

[0066] 1. Riding lawnmower (work vehicle) 2. Running vehicle 5. Lawn mowing equipment (working machine) 10 Control device 21 Engine 22 PTO clutch 23 PTO shaft N Constant rotational speed t1 1st hour t2 Second hour t3 3rd hour t4 4th hour

Claims

1. The vehicle body and The engine mounted on the aforementioned vehicle body, A PTO shaft that outputs the power of the aforementioned engine to the outside, A work machine to which power is transmitted from the PTO shaft, A control device that enables constant engine speed control based on a set constant rotational speed, A rise time setting means that can set the time it takes for the engine speed to rise until it reaches the constant speed to be set to the first hour, and A work vehicle equipped with the following features.

2. The system includes a PTO clutch that performs on / off operations to connect and disconnect the power transmitted to the PTO shaft, The control device is The connection time, which is the time from the start of control to engage the PTO clutch until the PTO clutch is engaged, can be changed. In the standard mode, the PTO clutch engagement time is the third time, A slow mode in which the PTO clutch engagement time is longer than the third time, for a fourth time. It has, The work vehicle according to claim 1, wherein the time it takes for the engine speed to increase is changed according to the engagement time of the PTO clutch.

3. The control device is In the standard mode, the time it takes for the engine speed to increase is set to the first time, and in the slow mode, the time it takes for the engine speed to increase is set to the second time, which is longer than the first time. The first time is longer than the third time. The work vehicle according to claim 2, wherein the second time is longer than the fourth time.

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